Patent Publication Number: US-2022221695-A1

Title: Optical imaging system and mobile electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 16/421,986 filed on May 24, 2019, which claims the benefit under 35 U.S.C. 119(a) of Korean Patent Application Nos. 10-2018-0121780 filed on Oct. 12, 2018, and 10-2018-0084858 filed on Jul. 20, 2018, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     1. Field 
     This application relates to an optical imaging system and mobile electronic device. 
     2. Description of the Background 
     Recently, mobile communications terminals have been provided with camera modules, enabling video calling and image capturing. In addition, as the utilization of camera modules mounted in mobile communications terminals has increased, camera modules for mobile communications terminals have gradually been required to have higher resolution and higher performance. 
     However, since there is a trend for mobile communications terminals to be gradually miniaturized and lightened, there are limitations in realizing camera modules having high resolution and high performance. 
     In particular, it is difficult to obtain an optical zoom effect in a camera used in mobile communications terminals due to size limitations, and it is difficult to capture a subject at various distances. 
     The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In one general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens sequentially disposed from an object side, wherein the first lens has negative refractive power, an image side surface thereof is concave, and an angle of view of the optical imaging system including the first lens to the sixth lens is 100° or more. When a focal length of the first lens is f1_1, and a total focal length of the optical imaging system including the first lens to the sixth lens is F1, 1.0&lt;|f1_1/F1|&lt;2.0 is satisfied. 
     When a distance from an object side surface of the first lens to an imaging surface of an image sensor is TTL1, TTL1/F1&gt;2.0 may be satisfied. 
     When a focal length of the third lens is f3_1, −1.0&lt;f3_1/f1_1&lt;0 may be satisfied. 
     When an Abbe number of the first lens is v1_1, and an Abbe number of the second lens is v2_1, v1_1−v2_1&gt;30 may be satisfied. 
     v2_1&lt;26 may be satisfied. 
     When an average value of an Abbe number of the third lens and an Abbe number of the fourth lens is AVR(v3_1, v4_1), an average value of an Abbe number of the fifth lens and an Abbe number of the sixth lens is AVR(v5_1, v6_1), the Abbe number of the third lens is v3_1, the Abbe number of the fourth lens is v4_1, the Abbe number of the fifth lens is v5_1, and the Abbe number of sixth lens is v6_1, AVR(v3_1, v4_1)&gt;55 and AVR(v5_1, v6_1)&lt;21 may be satisfied. 
     When an average value of the Abbe number of the third lens and the Abbe number of the fifth lens is AVR(v3_1, v5_1), an average value of the Abbe number of the fourth lens and the Abbe number of the sixth lens is AVR(v4_1, v6_1), AVR(v3_1, v5_1)&gt;55 and AVR(v4_1, v6_1)&lt;24 may be satisfied. 
     v2_1+v6_1&lt;v3_1 may be satisfied. 
     The second lens and the third lens may each have positive refractive power. 
     The first lens to the sixth lens may be made of a plastic material, and the first lens and the second lens may be made of plastic materials having different optical characteristics from each other. 
     The fifth lens to the sixth lens may be made of plastic materials having different optical characteristics from each other. 
     A mobile electronic device may include the optical imaging system, the optical imaging system may further include an image sensor to convert light incident through the first lens to the sixth lens to an electrical signal, and a display unit disposed on a surface of the mobile electronic device to display an image based on the electrical signal. 
     The mobile electronic device may further include a second optical imaging system comprising a second image sensor, and a third optical imaging system comprising a third image sensor, the optical imaging system, the second optical imaging system, and the third optical imaging systems may have different angles of view from each other, and the display unit may display an image synthesized from the image sensor, the second image sensor, and the third image sensor. 
     In another general aspect, an optical imaging system includes a first optical imaging system, a second optical imaging system, and a third optical imaging system having different angles of view from each other. Among the first optical imaging system to the third optical imaging system, when an angle of view of an optical imaging system having the widest angle of view is FOV1, and an angle of view of an optical imaging system having the narrowest angle of view is FOV3, 1.5&lt;FOV1/FOV3&lt;4.0 is satisfied. The optical imaging system having the widest angle of view among the first optical imaging system to the third optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, sequentially disposed from an object side. The first lens has negative refractive power, an image side surface thereof is concave, and an angle of view of an optical imaging system comprising the first lens to the sixth lens is 100° or more. When a focal length of the first lens is f1_1, and a total focal length of the optical imaging system including the first lens to the sixth lens is F1, 1.0&lt;|f1_1/F1|&lt;2.0 is satisfied. 
     When a focal length obtained by converting a total focal length of the first optical imaging system into 35 mm format is F1′, and a focal length obtained by converting a total focal length of the third optical imaging system into 35 mm format is F3′, 2.5≤F3′/F1′ may be satisfied. 
     When a focal length obtained by converting the total focal length of the second optical imaging system into 35 mm format is F2′, 1.5≤F2′/F1′≤2.5 may be satisfied. 
     The optical imaging system may be a mobile electronic device, and may further include a first image sensor to convert light incident through the first lens to the sixth lens to an electrical signal, and a display unit disposed on a surface of the mobile electronic device to display an image based on the electrical signal. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a mobile electronic device according to an embodiment of the present disclosure. 
         FIG. 2  is a configuration diagram of a first optical imaging system according to a first embodiment of the present disclosure. 
         FIG. 3  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 2 . 
         FIG. 4  is a configuration diagram of the first optical imaging system according to a second embodiment of the present disclosure. 
         FIG. 5  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 4 . 
         FIG. 6  is a configuration diagram of the first optical imaging system according to a third embodiment of the present disclosure. 
         FIG. 7  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 6 . 
         FIG. 8  is a configuration diagram of the first optical imaging system according to a fourth embodiment of the present disclosure. 
         FIG. 9  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 8 . 
         FIG. 10  is a configuration diagram of the first optical imaging system according to a fifth embodiment of the present disclosure. 
         FIG. 11  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 10 . 
         FIG. 12  is a configuration diagram of the first optical imaging system according to a sixth embodiment of the present disclosure. 
         FIG. 13  is a curve representing aberration characteristics of the first optical imaging system illustrated in  FIG. 12 . 
         FIG. 14  is a configuration diagram of a second optical imaging system according to a first embodiment of the present disclosure. 
         FIG. 15  is a curve representing aberration characteristics of the second optical imaging system illustrated in  FIG. 14 . 
         FIG. 16  is a configuration diagram of the second optical imaging system according to a second embodiment of the present disclosure. 
         FIG. 17  is a curve representing aberration characteristics of the second optical imaging system illustrated in  FIG. 16 . 
         FIG. 18  is a configuration diagram of the second optical imaging system according to a third embodiment of the present disclosure. 
         FIG. 19  is a curve representing aberration characteristics of the second optical imaging system illustrated in  FIG. 18 . 
         FIG. 20  is a partially enlarged view of a first lens of the second optical imaging system illustrated in  FIG. 14 . 
         FIG. 21  is a configuration diagram of a third optical imaging system according to a first embodiment of the present disclosure. 
         FIG. 22  shows aspherical surface coefficients for each surface of a first lens to a sixth lens of the third optical imaging system illustrated in  FIG. 21 . 
         FIG. 23  is a curve representing aberration characteristics of the third optical imaging system illustrated in  FIG. 21 . 
         FIG. 24  is a configuration diagram of the third optical imaging system according to a second embodiment of the present disclosure. 
         FIG. 25  shows aspherical surface coefficients for each surface of a first lens to a sixth lens of the third optical imaging system illustrated in  FIG. 24 . 
         FIG. 26  is a curve representing aberration characteristics of the third optical imaging system illustrated in  FIG. 24 . 
         FIG. 27  is a configuration diagram of the third optical imaging system according to a third embodiment of the present disclosure. 
         FIG. 28  shows aspherical surface coefficients for each surface of a first lens to a sixth lens of the third optical imaging system illustrated in  FIG. 27 . 
         FIG. 29  is a curve representing aberration characteristics of the third optical imaging system illustrated in  FIG. 27 . 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of this application. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of the disclosure of this application, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness. 
     The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of the disclosure of this application. Hereinafter, while embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, it is noted that examples are not limited to the same. 
     Throughout the specification, when an element, such as a layer, region, or substrate, is described as being “on,” “connected to,” or “coupled to” another element, it may be directly “on,” “connected to,” or “coupled to” the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there can be no other elements intervening therebetween. 
     As used herein, the term “and/or” includes any one and any combination of any two or more of the associated listed items; likewise, “at least one of” includes any one and any combination of any two or more of the associated listed items. 
     Although terms such as “first,” “second,” and “third” may be used herein to describe various members, components, regions, layers, or sections, these members, components, regions, layers, or sections are not to be limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or section from another member, component, region, layer, or section. Thus, a first member, component, region, layer, or section referred to in examples described herein may also be referred to as a second member, component, region, layer, or section without departing from the teachings of the examples, and similarly, the second member, component, region, layer, or section may also be referred to as a first member, component, region, layer, or section. 
     Spatially relative terms such as “above,” “upper,” “below,” and “lower” may be used herein for ease of description to describe one element&#39;s relationship to another element as shown in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being “above” or “upper” relative to another element will then be “below” or “lower” relative to the other element. Thus, the term “above” encompasses both the above and below orientations depending on the spatial orientation of the device. The device may also be oriented in other ways (for example, rotated 90 degrees or at other orientations), and the spatially relative terms used herein are to be interpreted accordingly. 
     The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. The articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “includes,” and “has” specify the presence of stated features, numbers, operations, members, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, members, elements, and/or combinations thereof. 
     Due to manufacturing techniques and/or tolerances, variations of the shapes shown in the drawings may occur. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing. 
     The features of the examples described herein may be combined in various ways as will be apparent after an understanding of the disclosure of this application. Further, although the examples described herein have a variety of configurations, other configurations are possible as will be apparent after an understanding of the disclosure of this application. 
     Herein, it is noted that use of the term “may” with respect to an example, for example, as to what an example may include or implement, means that at least one example exists in which such a feature is included or implemented while all examples are not limited thereto. 
     In the following lens configuration diagrams, thicknesses, sizes and sizes of lenses have been slightly exaggerated for convenience of explanation. Particularly, shapes of spherical surfaces or aspherical surfaces suggested in the lens configuration diagrams are suggested by way of example. The shapes of the spherical surfaces or the aspherical surfaces are not limited to those illustrated in the lens configuration diagrams. 
     In addition, in each lens, a first surface may refer to a surface close to an object side (an object-side surface) and a second surface may refer to a surface close to an image side (an image-side surface). In addition, in the present specification, numerical values of a radius of curvature, a thickness, a distance, a focal length, and the like of a lens may all be in mm, and an unit of an angle is in degrees. 
     In an explanation of a shape of each lens, a convex shape of one surface may mean that a paraxial region of the surface may be convex, and a concave shape of one surface may mean that a paraxial region of the surface may be concave. Therefore, even when one surface of the lens is described as a convex shape, an edge portion of the lens may be concave. Similarly, even when one surface of the lens is described as a concave shape, an edge portion of the lens may be convex. 
     The paraxial region may mean a narrow region near and including an optical axis. 
     Meanwhile, an aspherical surface of a lens may be represented by following Equation 1. 
     
       
         
           
             
               
                 
                   Z 
                   = 
                   
                     
                       
                         cY 
                         2 
                       
                       
                         1 
                         + 
                         
                           
                             1 
                             - 
                             
                               
                                 ( 
                                 
                                   1 
                                   + 
                                   K 
                                 
                                 ) 
                               
                               ⁢ 
                               
                                 c 
                                 2 
                               
                               ⁢ 
                               
                                 Y 
                                 2 
                               
                             
                           
                         
                       
                     
                     + 
                     
                       AY 
                       4 
                     
                     + 
                     
                       BY 
                       6 
                     
                     + 
                     
                       CY 
                       8 
                     
                     + 
                     
                       DY 
                       
                         1 
                         ⁢ 
                         0 
                       
                     
                     + 
                     
                       EY 
                       
                         1 
                         ⁢ 
                         2 
                       
                     
                     + 
                     
                       FY 
                       
                         1 
                         ⁢ 
                         4 
                       
                     
                     + 
                     
                       GY 
                       
                         1 
                         ⁢ 
                         6 
                       
                     
                     + 
                     
                       HY 
                       18 
                     
                     + 
                     … 
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     where c is a curvature of a lens (a reciprocal of a radius of curvature), k is a conic constant, and Y is a distance from an arbitrary point on an aspherical surface of a lens to an optical axis. Further, constants A to H may mean aspherical constants. Z (or SAG) may represent a distance from an arbitrary point on an aspherical surface of a lens to an apex of the aspherical surface in a direction of the optical axis. 
     An aspect of the present disclosure is to provide an optical imaging system having a wide angle of view and being bright. Another aspect of the present disclosure is to provide an optical imaging system capable of capturing a subject at various distances. 
     Referring to  FIG. 1 , a mobile electronic device  4  according to an embodiment of the present disclosure may be provided with a display  5  and an optical imaging system, and the optical imaging system may include a plurality of optical imaging systems. In addition, respective optical imaging systems may include a plurality of lenses. 
     For example, the optical imaging system of the mobile electronic device  4  may be provided with a first optical imaging system  1 , a second optical imaging system  2  and a third optical imaging system  3 . 
     The first optical imaging system  1 , the second optical imaging system  2  and the third optical imaging system  3  may be configured to have different angles of view from each other. 
     The first optical imaging system  1  may be configured to have the widest angle of view (for example, a wide angle lens) and the third optical imaging system  3  may be configured to have the narrowest angle of view (for example, a telephoto lens). The second optical imaging system  2  may have a narrower angle of view than the first optical imaging system  1  and may have a wider angle of view than the third optical imaging system  3 . 
     As an example, an angle of view (FOV1) of the first optical imaging system  1  may be FOV1≥100°, an angle of view (FOV2) of the second optical imaging system  2  may be 70°≤FOV2&lt;100° and an angle of view (FOV3) of the third optical imaging system  3  may be FOV3&lt;54°. Meanwhile, the angle of view (FOV2) of the second optical imaging system  2  may be 60°≤FOV2&lt;100°. 
     In addition, TTL/F of the first optical imaging system  1  and the second optical imaging system  2  may be 1.0 or more, respectively, and TTL/F of the third optical imaging system  3  may be less than 1.0. Here, TTL may be a distance from an object side of a first lens of each optical imaging system to an imaging surface of an image sensor, and F may be a total focal length of each optical imaging system. 
     By implementing angles of view of the three optical imaging systems to be different from each other, an image of a subject may be captured at various distances, and a zoom function may be realized. 
     For example, an optical zoom effect for the same subject may be obtained by converting between the first optical imaging system  1 , the second optical imaging system  2 , and the third optical imaging system  3 . 
     In addition, since three images for one subject may be used (for example, synthesized) to generate a high-resolution image or a bright image, an image of a subject may be clearly captured even in a low-light environment. 
     The first optical imaging system  1  to the third optical imaging system  3  may satisfy the following conditional expressions. 
       1.5&lt;FOV1/FOV3&lt;4.0  [Conditional Expression 1]
 
       2.5≤ F 3′/ F 1′  [Conditional Expression 2]
 
       1.5≤ F 2′/ F 1′≤2.5  [Conditional Expression 3]
 
     In the conditional expressions, FOV1 may represent the angle of view of the first optical imaging system  1 , FOV3 may represent the angle of view of the third optical imaging system  3 , F1′ may represent a focal length in which the total focal length of the first optical imaging system  1  is converted into 35 mm format (based on an image sensor size of a 35 mm film camera), F2′ may represent a focal length in which the total focal length of the second optical imaging system  2  is converted into 35 mm format and F3′ may represent a focal length in which the total focal length of the third optical imaging system  3  is converted into 35 mm format. 
     Table 1 shows examples of the total focal length and the converted focal length of each embodiment of the first optical imaging system  1 , the second optical imaging system  2 , and the third optical imaging system  3 . In Table 1, F represents the total focal length of each embodiment, and F′ represents the focal length converted based on the image sensor size of the 35 mm film camera. The units may be mm. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Embodiment 
                 F 
                 F′ 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 First optical 
                 1 
                 2.21 
                 16.43 
               
               
                   
                 imaging system (1) 
                 2 
                 2.14 
                 15.91 
               
               
                   
                   
                 3 
                 1.837 
                 13.66 
               
               
                   
                   
                 4 
                 1.804 
                 13.46 
               
               
                   
                   
                 5 
                 1.804 
                 13.46 
               
               
                   
                   
                 6 
                 1.8 
                 13.43 
               
               
                   
                 Second optical 
                 1 
                 4.3 
                 25.14 
               
               
                   
                 imaging system (2) 
                 2 
                 4.31 
                 25.20 
               
               
                   
                   
                 3 
                 4.29 
                 25.02 
               
               
                   
                 Third optical 
                 1 
                 5.997 
                 49.71 
               
               
                   
                 imaging system (3) 
                 2 
                 6.001 
                 48.08 
               
               
                   
                   
                 3 
                 6.001 
                 49.55 
               
               
                   
                   
               
            
           
         
       
     
     Hereinafter, the first optical imaging system  1  will be described with reference to  FIGS. 2 to 13 . 
     The first optical imaging system  1  may satisfy at least one of the following conditional expressions. 
       FOV1≥100°  [Conditional Expression 4]
 
         Fno 1≥2.4  [Conditional Expression 5]
 
         TTL 1/ F 1&gt;2.0  [Conditional Expression 6]
 
       1.0&lt;| f 1_1/ F 1|&lt;2.0  [Conditional Expression 7]
 
       −1.0&lt; f 3_1/ f 1_1&lt;0  [Conditional Expression 8]
 
       0.5&lt; R 2_1/ F 1&lt;2.0  [Conditional Expression 9]
 
         v 2_1&lt;26  [Conditional Expression 10]
 
         v 1_1− v 2_1&gt;30  [Conditional Expression 11]
 
       AVR( v 3_1, v 4_1)&gt;55  [Conditional Expression 12]
 
       AVR( v 5_1, v 6_1)&lt;21  [Conditional Expression 13]
 
       AVR( v 3_1, v 5_1)&gt;55  [Conditional Expression 14]
 
       AVR( v 4_1, v 6_1)&lt;24  [Conditional Expression 15]
 
         v 2_1+ v 6_1&lt; v 3_1  [Conditional Expression 16]
 
     TTL1 may be a distance from an object side of the first lens of the first optical imaging system  1  to an imaging surface of an image sensor, F1 may be a total focal length of the first optical imaging system  1 , f1_1 may be a focal length of the first lens of the first optical imaging system  1 , f3_1 may be a focal length of the third lens of the first optical imaging system  1 , R2_1 may be a radius of curvature of image side surface of the first lens of the first optical imaging system  1 , v1_1 may be an Abbe number of the first lens of the first optical imaging system  1 , v2_1 may be an Abbe number of the second lens of the first optical imaging system  1 , v3_1 may be an Abbe number of the third lens of the first optical imaging system  1 , v4_1 may be an Abbe number of the fourth lens of the first optical imaging system  1 , v5_1 may be an Abbe number of the fifth lens of the first optical imaging system  1 , and v6_1 may be an Abbe number of the sixth lens of the first optical imaging system  1 . 
     In addition, AVR(v3_1, v4_1) may be an average value of the Abbe number of the third lens and the Abbe number of the fourth lens, AVR(v5_1, v6_1) may be an average value of the Abbe number of the fifth lens and the Abbe number of the sixth lens, AVR(v3_1, v5_1) may be an average value of the Abbe number of the third lens and the Abbe number of the fifth lens, and AVR(v4_1, v6_1) may be an average value of the Abbe number of the fourth lens and the Abbe number of the sixth lens. 
     Referring to  FIGS. 2 and 3 , a first embodiment of the first optical imaging system  1  of the present disclosure may include an optical system including a first lens  11 , a second lens  12 , a third lens  13 , a fourth lens  14 , a fifth lens  15  and a sixth lens  16 , and may further include an infrared block filter  17  (hereinafter, referred to as a ‘filter’) and an image sensor  18 . 
     The first lens  11  to the sixth lens  16  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  11  to the sixth lens  16  may be formed of a plastic material. 
     Table 2 illustrates lens characteristics (a radius of curvature, a thickness of a lens, or a distance between lenses, a refractive index, an Abbe number, and a focal length) of respective lenses. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −3.361 
                 0.375 
                 1.544 
                 56.1 
                 −3.318 
               
               
                 S2 
                   
                 4.083 
                 0.457 
               
               
                 S3 
                 Second lens 
                 4.37854 
                 0.250 
                 1.639 
                 23.5 
                 8.197 
               
               
                 S4 
                   
                 25.098 
                 0.084 
               
               
                 S5 
                 Third lens 
                 −3.327 
                 0.599 
                 1.544 
                 56.1 
                 2.729 
               
               
                 S6 
                   
                 −1.094 
                 0.030 
               
               
                 S7 
                 Fourth lens 
                 4.400 
                 0.519 
                 1.544 
                 56.1 
                 2.816 
               
               
                 S8 
                   
                 −2.265 
                 0.030 
               
               
                 S9 
                 Fifth lens 
                 −5.879 
                 0.200 
                 1.671 
                 19.2 
                 −3.339 
               
               
                 S10 
                   
                 3.727 
                 0.993 
               
               
                 S11 
                 Sixth lens 
                 1.905 
                 0.483 
                 1.65 
                 21.5 
                 −15.765 
               
               
                 S12 
                   
                 1.447 
                 0.251 
               
               
                 S13 
                 Filter 
                 Infinity 
                 0.210 
                 1.517 
                 64.2 
               
               
                 S14 
                   
                 Infinity 
                 0.620 
               
               
                 S15 
                 Imaging surface 
                 Infinity 
                 0.02000 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 2.21 mm, the angle of view FOV1 may be 117.4°, Fno1 may be 2.2, TTL1 may be 5.12 mm, and BFL1 may be 1.101 mm. 
     Here, Fno1 may be a number (f-number) representing brightness of the first optical imaging system, TTL1 may be a distance from the object side surface of the first lens  11  of the first optical imaging system  1  to the imaging surface of the image sensor  18 , and BFL1 may be a distance from the image side surface of the sixth lens  16  of the imaging surface of the image sensor  18 . 
     In the first embodiment of the first optical imaging system  1 , the first lens  11  may have negative refractive power, and first and second surfaces of the first lens  11  may be concave in a paraxial region. 
     In addition, at least one inflection point may be formed on the first surface of the first lens  11 . For example, the first surface of the first lens  11  may be concave in the paraxial region and may be convex toward an edge. 
     The second lens  12  may have positive refractive power, a first surface of the second lens  12  may be convex in a paraxial region and a second surface of the second lens  12  may be concave in the paraxial region. 
     The first lens  11  and the second lens  12  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  11  and the second lens  12  may be different from each other. 
     A stop ST may be disposed between the first lens  11  and the second lens  12 . 
     The third lens  13  may have positive refractive power, a first surface of the third lens  13  may be concave in a paraxial region, and a second surface of the third lens  13  may be convex in the paraxial region. 
     The second lens  12  and the third lens  13  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  12  and the third lens  13  may be different from each other. 
     The fourth lens  14  may have positive refractive power, and first and second surfaces of the fourth surface  4  may be convex in a paraxial region. 
     The fifth lens  15  may have negative refractive power, and first and second surfaces of the fifth lens  15  may be concave in a paraxial region. 
     The sixth lens  16  may have negative refractive power, and a first surface of the sixth lens  16  may be convex in a paraxial region, and a second surface of the sixth lens  16  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first surface and the second surface of the sixth lens  16 . For example, the first surface of the sixth lens  16  may be convex in the paraxial region, and may be concave toward an edge. The second surface of the sixth lens  16  may be concave in the paraxial region and may be concave toward the edge. 
     Meanwhile, the fifth lens  15  and the sixth lens  16  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  15  and the sixth lens  16  may be different from each other. In addition, the Abbe number of the fifth lens  15  and the sixth lens  16  may be 22 or less. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  11  to the sixth lens  16  may all be aspherical surfaces. For example, each surface of the first lens  11  to the sixth lens  16  may have an aspherical surface coefficient as shown in Table 3. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0.383517 
                 0.509874 
                 −0.76166 
                 1.228256 
                 −1.53364 
                 1.315349 
                 −0.70922 
                 0.214811 
                 −0.02765 
               
               
                 S2 
                 15.75935 
                 0.391738 
                 3.988743 
                 −32.3712 
                 136.6511 
                 −324.331 
                 424.4204 
                 −263.113 
                 45.62338 
               
               
                 S3 
                 −12.8954 
                 −0.05628 
                 −0.36079 
                 −0.79442 
                 3.085484 
                 −22.6953 
                 54.94171 
                 −47.9911 
                 0 
               
               
                 S4 
                 99 
                 0.17198 
                 −1.2445 
                 11.07723 
                 −49.7164 
                 115.2839 
                 −143.356 
                 75.35661 
                 0 
               
               
                 S5 
                 −35.1844 
                 0.067687 
                 0.421988 
                 1.563292 
                 −4.95337 
                 1.194026 
                 6.22432 
                 −4.54715 
                 0 
               
               
                 S6 
                 0.354807 
                 0.209891 
                 −1.03819 
                 3.221125 
                 −0.79106 
                 −18.3475 
                 48.3397 
                 −50.0839 
                 19.27644 
               
               
                 S7 
                 −38.4699 
                 0.126642 
                 −0.93239 
                 2.884888 
                 −5.0212 
                 5.27206 
                 −3.01827 
                 0.684177 
                 0 
               
               
                 S8 
                 2.708338 
                 0.584433 
                 −2.97325 
                 7.83848 
                 −11.4932 
                 8.588369 
                 −1.18423 
                 −2.30266 
                 1.027511 
               
               
                 S9 
                 0.149678 
                 0.615758 
                 −1.95322 
                 3.856699 
                 −4.28251 
                 1.105887 
                 2.554504 
                 −2.62588 
                 0.763076 
               
               
                 S10 
                 1.112265 
                 0.187466 
                 0.008211 
                 −0.45112 
                 0.582211 
                 −0.36362 
                 0.117567 
                 −0.0157 
                 0 
               
               
                 S11 
                 −6.56077 
                 −0.12142 
                 −0.00555 
                 0.03359 
                 −0.02194 
                 0.007567 
                 −0.0013 
                  8.8E−05 
                 0 
               
               
                 S12 
                 −0.74052 
                 −0.24748 
                 0.103115 
                 −0.03794 
                 0.00942 
                 −0.00144 
                 0.000105 
                 −1.6E−06 
                 0 
               
               
                   
               
            
           
         
       
     
     In addition, an optical imaging system thus configured may have aberration characteristics as shown in  FIG. 3 . 
     Referring to  FIGS. 4 and 5 , according to a second embodiment of the present disclosure, a first optical imaging system  1  may include an optical imaging system including a first lens  21 , a second lens  22 , a third lens  23 , a fourth lens  24 , a fifth lens  25 , and a sixth lens  26 , sequentially disposed from an object side, and may further include a filter  27  and an image sensor  28 . 
     The first lens  21  to the sixth lens  26  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  21  to the sixth lens  26  may be formed of a plastic material. 
     Table 4 shows lens characteristics (a radius of curvature, a thickness of a lens, a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −8.183 
                 0.404 
                 1.544 
                 56.1 
                 −3.390 
               
               
                 S2 
                   
                 2.433 
                 0.414 
               
               
                 S3 
                 Second lens 
                 4.40088 
                 0.262 
                 1.65 
                 21.5 
                 9.820 
               
               
                 S4 
                   
                 13.576 
                 0.085 
               
               
                 S5 
                 Third lens 
                 −3.667 
                 0.582 
                 1.544 
                 56.1 
                 2.582 
               
               
                 S6 
                   
                 −1.075 
                 0.030 
               
               
                 S7 
                 Fourth lens 
                 5.618 
                 0.546 
                 1.544 
                 56.1 
                 2.545 
               
               
                 S8 
                   
                 −1.782 
                 0.049 
               
               
                 S9 
                 Fifth lens 
                 −2.38070 
                 0.220 
                 1.661 
                 20.35 
                 −2.781 
               
               
                 S10 
                   
                 8.69914 
                 0.835 
               
               
                 S11 
                 Sixth lens 
                 1.664 
                 0.586 
                 1.65 
                 21.5 
                 72.707 
               
               
                 S12 
                   
                 1.484 
                 0.258 
               
               
                 S13 
                 Filter 
                 Infinity 
                 0.210 
                 1.517 
                 64.2 
               
               
                 S14 
                   
                 Infinity 
                 0.621 
               
               
                 S15 
                 Imaging surface 
                 Infinity 
                 0.02000 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 2.14 mm, the angle of view FOV1 may be 117°, Fno1 may be 2.26, TTL1 may be 5.121 mm, and BFL1 may be 1.109 mm. 
     In the second embodiment of the first optical imaging system  1 , the first lens  21  may have negative refractive power, and first and second surfaces of the first lens  21  may be concave in a paraxial region. 
     In addition, at least one inflection point may be formed on the first surface of the first lens  21 . For example, the first surface of the first lens  21  may be concave in the paraxial region and may be convex toward an edge. 
     The second lens  22  may have positive refractive power, the first surface of the second lens  22  may be convex in the paraxial region, and the second surface of the second lens  22  may be concave in the paraxial region. 
     The first lens  21  and the second lens  22  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  21  and the second lens  22  may be different from each other. 
     The third lens  23  may have positive refractive power, a first surface of the third lens  23  may be concave in a paraxial region, and a second surface of the third lens  23  may be convex in the paraxial region. 
     The second lens  22  and the third lens  23  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe numbers of the second lens  22  and the third lens  23  may be different from each other. 
     A stop ST may be disposed between the second lens  22  and the third lens  23 . 
     The fourth lens  24  may have positive refractive power, and first and second surfaces of the fourth lens  24  may be convex in a paraxial region. 
     The fifth lens  25  may have negative refractive power, and first and second surfaces of the fifth lens  25  may be concave in a paraxial region. 
     The sixth lens  26  may have positive refractive power, a first surface of the sixth lens  26  may be convex in a paraxial region, and a second surface of the sixth lens  26  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  26 . For example, the first surface of the sixth lens  26  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  26  may be concave in the paraxial region and may be convex toward the edge. 
     Meanwhile, the fifth lens  25  and the sixth lens  26  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  25  and the sixth lens  26  may be different from each other. In addition, the Abbe number of the fifth lens  25  and the sixth lens  26  may be 22 or less. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  21  to the sixth lens  26  may all be aspherical surfaces. For example, respective surfaces of the first lens  21  to the sixth lens  26  may have aspherical surface coefficients as shown in Table 5. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0 
                 0.417375 
                 −0.50416 
                 0.630108 
                 −0.56681 
                 0.333316 
                 −0.11294 
                 0.017182 
               
               
                 S2 
                 3.437091 
                 0.681586 
                 0.169306 
                 −6.39824 
                 40.46252 
                 −120.254 
                 185.2559 
                 −118.319 
               
               
                 S3 
                 0 
                 −0.06345 
                 −0.56035 
                 5.073793 
                 −57.4869 
                 277.9519 
                 −688 
                 674.4575 
               
               
                 S4 
                 0 
                 0.120851 
                 0.218756 
                 −3.10847 
                 20.29634 
                 −71.2031 
                 111.7326 
                 −65.5863 
               
               
                 S5 
                 −33.5067 
                 0.101666 
                 0.42272 
                 −1.89908 
                 17.66911 
                 −59.5811 
                 83.57319 
                 −42.803 
               
               
                 S6 
                 0.419298 
                 −0.10736 
                 0.81216 
                 −3.00489 
                 9.711379 
                 −18.9891 
                 21.22636 
                 −9.00593 
               
               
                 S7 
                 −252.971 
                 −0.05899 
                 0.070133 
                 −0.73876 
                 2.83771 
                 −4.78613 
                 3.897587 
                 −1.24087 
               
               
                 S8 
                 1.156652 
                 0.642046 
                 −2.23005 
                 4.0212 
                 −4.57893 
                 3.572002 
                 −1.87938 
                 0.539453 
               
               
                 S9 
                 1 
                 0.82133 
                 −1.75515 
                 2.578652 
                 −2.8132 
                 2.044485 
                 −0.97817 
                 0.244166 
               
               
                 S10 
                 0 
                 0.144303 
                 0.22809 
                 −0.63909 
                 0.550139 
                 −0.2241 
                 0.040006 
                 −0.00164 
               
               
                 S11 
                 −8.7844 
                 −0.05242 
                 −0.09475 
                 0.068483 
                 −0.02537 
                 0.007137 
                 −0.00129 
                 9.92E−05 
               
               
                 S12 
                 −0.81081 
                 −0.20422 
                 0.059903 
                 −0.01304 
                 0.000771 
                 0.000437 
                 −0.00013 
                 1.08E−05 
               
               
                   
               
            
           
         
       
     
     In addition, an optical imaging system thus configured may have aberration characteristics shown in  FIG. 5 . 
     Referring to  FIGS. 6 and 7 , according to a third embodiment of the present disclosure, the first optical imaging system  1  may include an optical system including a first lens  31 , a second lens  32 , a third lens  33 , a fourth lens  34 , a fifth lens  35  and a sixth lens  36 , sequentially disposed from an object side, and may further include a filter  37  and an image sensor  38 . 
     The first lens  31  to the sixth lens  36  may be disposed to be spaced from each other by a predetermined distance along an optical axis, respectively. The first lens  31  to the sixth lens  36  may be formed of a plastic material. 
     Table 6 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −12.707 
                 0.300 
                 1.544 
                 56.1 
                 −3.362 
               
               
                 S2 
                   
                 2.166 
                 0.709 
               
               
                 S3 
                 Second lens 
                 1.63231 
                 0.292 
                 1.614 
                 25.9 
                 6.939 
               
               
                 S4 
                   
                 2.450 
                 0.197 
               
               
                 S5 
                 Stop 
                 Infinity 
                 0.070 
               
               
                 S6 
                 Third lens 
                 4.042 
                 0.653 
                 1.544 
                 56.1 
                 2.666 
               
               
                 S7 
                   
                 −2.149 
                 0.070 
               
               
                 S8 
                 Fourth lens 
                 −12.299 
                 0.220 
                 1.671 
                 19.2 
                 −6.606 
               
               
                 S9 
                   
                 7.11924 
                 0.134 
               
               
                 S10 
                 Fifth lens 
                 4.95200 
                 0.755 
                 1.544 
                 56.1 
                 2.083 
               
               
                 S11 
                   
                 −1.399 
                 0.373 
               
               
                 S12 
                 Sixth lens 
                 1.341 
                 0.300 
                 1.614 
                 25.9 
                 −3.106 
               
               
                 S13 
                   
                 0.72272 
                 0.257 
               
               
                 S14 
                 Filter 
                 Infinity 
                 0.210 
                 1.517 
                 64.2 
               
               
                 S15 
                   
                 Infinity 
                 0.620 
               
               
                 S16 
                 Imaging surface 
                 Infinity 
                 0.02000 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 1.837 mm, the angle of view FOV1 may be 117.8°, Fno1 may be 2.25, TTL1 may be 5.18 mm and, BFL1 may be 0.85 mm. 
     In a third embodiment of the first optical imaging system  1 , the first lens  31  may have negative refractive power, and first and second surfaces of the first lens  31  may be concave in a paraxial region. 
     At least one inflection point may be formed on the first surface of the first lens  31 . For example, the first surface of the first lens  31  may be concave in the paraxial region and may be convex toward an edge. 
     The second lens  32  may have positive refractive power, a first surface of the second lens  32  may be convex in the paraxial region and a second surface of the second lens  32  may be concave in the paraxial region. 
     The first lens  31  and the second lens  32  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  31  and the second lens  32  may be different from each other. 
     The third lens  33  may have positive refractive power, and first and second surfaces of the third lens  33  may be convex in a paraxial region. 
     The second lens  32  and the third lens  33  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  32  and the third lens  33  may be different from each other. 
     A stop ST may be disposed between the second lens  32  and the third lens  33 . 
     The fourth lens  34  may have negative refractive power, first and second surfaces of the fourth lens  34  may be concave in a paraxial region. 
     The fifth lens  35  may have positive refractive power, first and second surfaces of the fifth lens  35  may be convex in a paraxial region. 
     The sixth lens  36  may have negative refractive power, and a first surface of the sixth lens  36  may be convex in a paraxial region and a second surface of the sixth lens  36  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  36 . For example, the first surface of the sixth lens  36  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  36  may be concave in the paraxial region and may be convex toward the edge. 
     Meanwhile, the fifth lens  35  and the sixth lens  36  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  35  and the sixth lens  36  may be different from each other. In addition, the Abbe number of the sixth lens  36  may be 26 or less. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  31  to the sixth lens  36  may all be aspherical surfaces. For example, each surface of the first lens  31  to the sixth lens  36  may have an aspherical surface coefficient as shown in Table 7. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0 
                 0.37507 
                 −0.45440 
                 0.48627 
                 −0.38104 
                 0.20497 
                 −0.07064 
                 0.01400 
                 −0.00121 
               
               
                 S2 
                 0.51564 
                 0.47998 
                 −0.52098 
                 0.57001 
                 −0.39538 
                 0.09559 
                 0 
                 0 
                 0 
               
               
                 S3 
                 −2.93220 
                 −0.00537 
                 −0.14092 
                 −0.60218 
                 1.28988 
                 −0.65548 
                 0 
                 0 
                 0 
               
               
                 S4 
                 9.17220 
                 −0.05165 
                 −0.28642 
                 −0.01159 
                 1.51178 
                 −1.11276 
                 0 
                 0 
                 0 
               
               
                 S6 
                 19.98604 
                 −0.01047 
                 0.03335 
                 −0.22807 
                 0.17626 
                 0 
                 0 
                 0 
                 0 
               
               
                 S7 
                 3.74495 
                 0.05373 
                 −3.02475 
                 15.96820 
                 −49.52659 
                 88.38501 
                 −88.17166 
                 43.81596 
                 −7.03388 
               
               
                 S8 
                 139.06889 
                 0.02332 
                 −3.33453 
                 15.66493 
                 −43.87823 
                 75.23525 
                 −84.79839 
                 60.08267 
                 −19.54198 
               
               
                 S9 
                 0 
                 0.01770 
                 −1.65750 
                 6.21598 
                 −12.63317 
                 15.11076 
                 −10.81219 
                 4.41980 
                 −0.80714 
               
               
                 S10 
                 −15.57041 
                 0.05751 
                 −0.65490 
                 1.46125 
                 −1.69379 
                 1.09038 
                 −0.38011 
                 0.06401 
                 −0.00357 
               
               
                 S11 
                 −0.52500 
                 0.01203 
                 0.29322 
                 −0.76574 
                 1.04146 
                 −0.75964 
                 0.31025 
                 −0.06784 
                 0.00625 
               
               
                 S12 
                 −16.35061 
                 −0.39724 
                 0.11990 
                 0.08823 
                 −0.11480 
                 0.05442 
                 −0.01152 
                 0.00073 
                 0.00004 
               
               
                 S13 
                 −4.77091 
                 −0.28041 
                 0.21129 
                 −0.11309 
                 0.04180 
                 −0.01075 
                 0.00184 
                 −0.00019 
                 0.00001 
               
               
                   
               
            
           
         
       
     
     The optical imaging system thus configured may have aberration characteristics as shown in  FIG. 7 . 
     Referring to  FIGS. 8 and 9 , according to a fourth embodiment of the present disclosure, a first optical imaging system  1  may include an optical imaging system including a first lens  41 , a second lens  42 , a third lens  43 , a fourth lens  44 , a fifth lens  45 , and a sixth lens  46 , and may further include a filter  47  and an image sensor  48 . 
     The first lens  41  to the sixth lens  46  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  41  to the sixth lens  46  may be formed of a plastic material. 
     Table 8 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, and an Abbe number) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −79.907 
                 0.300 
                 1.544 
                 56.1 
                 −3.354 
               
               
                 S2 
                   
                 1.879 
                 0.859 
               
               
                 S3 
                 Second lens 
                 1.55413 
                 0.374 
                 1.614 
                 25.9 
                 5.771 
               
               
                 S4 
                   
                 2.495 
                 0.287 
               
               
                 S5 
                 Stop 
                 Infinity 
                 0.070 
               
               
                 S6 
                 Third lens 
                 4.767 
                 0.642 
                 1.544 
                 56.1 
                 2.544 
               
               
                 S7 
                   
                 −1.870 
                 0.173 
               
               
                 S8 
                 Fourth lens 
                 −2.646 
                 0.220 
                 1.671 
                 19.2 
                 −4.024 
               
               
                 S9 
                   
                 −85.11910 
                 0.128 
               
               
                 S10 
                 Fifth lens 
                 10.22393 
                 0.869 
                 1.544 
                 56.1 
                 3.294 
               
               
                 S11 
                   
                 −2.120 
                 0.338 
               
               
                 S12 
                 Sixth lens 
                 0.982 
                 0.517 
                 1.614 
                 25.9 
                 499.988 
               
               
                 S13 
                   
                 0.78646 
                 0.422 
               
               
                 S14 
                 Filter 
                 Infinity 
                 0.110 
                 1.517 
                 64.2 
               
               
                 S15 
                   
                 Infinity 
                 0.520 
               
               
                 S16 
                 Imaging surface 
                 Infinity 
                 0.01955 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 1.804 mm, FOV1 may be 121.4°, Fno1 may be 1.97, TTL1 may be 5.85 mm, and, BFL1 may be 1.072 mm. 
     In a fourth embodiment of the first optical imaging system  1 , the first lens  41  may have negative refractive power, and first and second surfaces of the first lens  41  may be concave in a paraxial region. 
     In addition, at least one inflection point may be formed on the first surface of the first lens  41 . For example, the first lens  41  may be concave in the paraxial region and may be convex toward an edge. 
     The second lens  42  may have positive refractive power, a first surface of the second lens  42  may be convex in a paraxial region, and a second surface of the second lens  42  may be concave in the paraxial region. 
     The first lens  41  and the second lens  42  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  41  and the second lens  42  may be different from each other. 
     The third lens  43  may have positive refractive power, and first and second surfaces of the third lens  43  may be convex in a paraxial region. 
     The second lens  42  and the third lens  43  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  42  and the third lens  43  may be different from each other. 
     A stop ST may be disposed between the second lens  42  and the third lens  43 . 
     The fourth lens  44  may have negative refractive power, a first surface of the fourth lens  44  may be concave in a paraxial region, and a second surface of the fourth lens  44  may be convex in the paraxial region. 
     The fifth lens  45  may have positive refractive power, and first and second surfaces of the fifth lens  45  may be convex in a paraxial region. 
     The sixth lens  46  may have positive refractive power, and a first surface of the sixth lens  46  may be convex in a paraxial region, and a second surface of the sixth lens  46  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on first and second surfaces of the sixth lens  46 . For example, the first surface of the sixth lens  46  may be convex in a paraxial region and may be concave toward an edge. The second surface of the sixth lens  46  may be concave in the paraxial region and may be convex toward the edge. 
     Meanwhile, the fifth lens  45  and the sixth lens  46  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  45  and the sixth lens  46  may be different from each other. In addition, the Abbe number of the sixth lens  46  may be 26 or less. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  41  to the sixth lens  46  may all be aspherical surfaces. For example, each surface of the first lens  41  to the sixth lens  46  may have an aspherical surface coefficient as shown in Table 9. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0 
                 0.13461 
                 −0.11275 
                 0.07155 
                 −0.03302 
                 0.01064 
                 −0.00225 
                 0.00028 
                 −0.00002 
               
               
                 S2 
                 −0.12380 
                 0.15303 
                 −0.12086 
                 0.04324 
                 −0.00701 
                 −0.00075 
                 0 
                 0 
                 0 
               
               
                 S3 
                 0.36526 
                 −0.00989 
                 0.04598 
                 −0.16314 
                 0.30176 
                 −0.13581 
                 0 
                 0 
                 0 
               
               
                 S4 
                 9.74753 
                 0.04119 
                 0.04536 
                 −0.18594 
                 0.70953 
                 −0.32574 
                 0 
                 0 
                 0 
               
               
                 S6 
                 16.55517 
                 −0.02366 
                 0.07207 
                 −0.22846 
                 0.19689 
                 0 
                 0 
                 0 
                 0 
               
               
                 S7 
                 2.41508 
                 −0.08211 
                 −0.56627 
                 3.77134 
                 −13.65308 
                 28.03459 
                 −33.64668 
                 22.16565 
                 −6.01660 
               
               
                 S8 
                 4.88732 
                 −0.27254 
                 −0.36865 
                 2.15281 
                 −2.91809 
                 −3.85609 
                 13.73763 
                 −12.04532 
                 3.44030 
               
               
                 S9 
                 0 
                 −0.17059 
                 −0.51107 
                 2.45925 
                 −4.80991 
                 5.08864 
                 −3.01988 
                 0.99032 
                 −0.14835 
               
               
                 S10 
                 −15.57278 
                 0.01072 
                 −0.39935 
                 1.00426 
                 −1.27255 
                 0.92269 
                 −0.39324 
                 0.09455 
                 −0.01042 
               
               
                 S11 
                 0.31182 
                 −0.38854 
                 0.98521 
                 −1.60100 
                 1.72351 
                 −1.14397 
                 0.45209 
                 −0.09779 
                 0.00890 
               
               
                 S12 
                 −5.15036 
                 −0.19741 
                 0.03887 
                 0.01071 
                 −0.00269 
                 −0.00402 
                 0.00219 
                 −0.00041 
                 0.00003 
               
               
                 S13 
                 −3.18332 
                 −0.16964 
                 0.09686 
                 −0.04171 
                 0.01326 
                 −0.00306 
                 0.00047 
                 −0.00004 
                 0.00000 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics shown in  FIG. 9 . 
     Referring to  FIGS. 10 and 11 , according to a fifth embodiment of the present disclosure, a first optical imaging system  1  may include an optical system including a first lens  51 , a second lens  52 , a third lens  53 , a fourth lens  54 , a fifth lens  55 , and a sixth lens  56 , sequentially disposed from an object side, and may further include a filter  57  and an image sensor  58 . 
     The first lens  51  to the sixth lens  56  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  51  to the sixth lens  56  may be formed of a plastic material. 
     Table 10 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 10 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −27.834 
                 0.300 
                 1.544 
                 56.1 
                 −2.051 
               
               
                 S2 
                   
                 1.172 
                 0.400 
               
               
                 S3 
                 Second lens 
                 1.57057 
                 0.628 
                 1.614 
                 25.9 
                 3.649 
               
               
                 S4 
                   
                 4.350 
                 0.264 
               
               
                 S5 
                 Third lens 
                 5.06581 
                 0.794 
                 1.544 
                 56.1 
                 1.975 
               
               
                 S6 
                   
                 −1.295 
                 0.030 
               
               
                 S7 
                 Fourth lens 
                 −1.736 
                 0.230 
                 1.671 
                 19.2 
                 −7.907 
               
               
                 S8 
                   
                 −2.702 
                 0.379 
               
               
                 S9 
                 Fifth lens 
                 −3.41613 
                 0.950 
                 1.544 
                 56.1 
                 2.375 
               
               
                 S10 
                   
                 −1.03316 
                 0.030 
               
               
                 S11 
                 Sixth lens 
                 1.893 
                 0.521 
                 1.614 
                 25.9 
                 −3.608 
               
               
                 S12 
                   
                 0.917 
                 0.418 
               
               
                 S13 
                 Filter 
                 Infinity 
                 0.110 
                 1.517 
                 64.2 
               
               
                 S14 
                   
                 Infinity 
                 0.801 
               
               
                 S15 
                 Imaging surface 
                 Infinity 
                 0.01955 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 1.804 mm, an angle of view FOV1 may be 126.9°, Fno1 may be 1.97, TTL1 may be 5.875 mm, and BFL1 may be 1.348 mm. 
     In a fifth embodiment of the first optical imaging system  1 , the first lens  51  may have negative refractive power, and first and second surfaces of the first lens  51  may be concave in a paraxial region. 
     In addition, at least one inflection point may be formed on the first surface of the first lens  51 . For example, the first surface of the first lens  51  may be concave in the paraxial region and may be convex toward an edge. 
     The second lens  52  may have positive refractive power, a first surface of the second lens  52  may be convex in a paraxial region, and a second surface of the second lens  52  may be concave in the paraxial region. 
     The first lens  51  and the second lens  52  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  51  and the second lens  52  may be different from each other. 
     The third lens  53  may have positive refractive power, and first and second surfaces of the third lens  53  may be convex in a paraxial region. 
     The second lens  52  and the third lens  53  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  52  and the third lens  53  may be different from each other. 
     A stop ST may be disposed between the second lens  52  and the third lens  53 . 
     The fourth lens  54  may have negative refractive power, a first surface of the fourth lens  54  may be concave in a paraxial region, and a second surface of the fourth lens  54  may be convex in the paraxial region. 
     The fifth lens  55  may have positive refractive power, a first surface of the fifth lens  55  may be concave in a paraxial region, and a second surface of the fifth lens  55  may be convex in the paraxial region. 
     The sixth lens  56  may have negative refractive power, a first surface of the sixth lens  56  may be convex, in a paraxial region and a second surface of the sixth lens  56  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  56 . For example, the first surface of the sixth lens  56  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  56  may be concave in the paraxial region and may be convex toward the edge. 
     Meanwhile, the fifth lens  55  and the sixth lens  56  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  55  and the sixth lens  56  may be different from each other. In addition, the Abbe number of the sixth lens  56  may be 26 or less. 
     Meanwhile, at least one of object side surfaces and image side surfaces of the first lens  51  to the sixth lens  56  may be an aspherical surface. For example, each surface of the first lens  51  to the sixth lens  56  may have an aspherical surface coefficient as shown in Table 11. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0 
                 0.065483 
                 −0.03968 
                 0.021116 
                 −0.00729 
                 0.001519 
                 −0.00017 
                 8.24E−06 
               
               
                 S2 
                 0 
                 −0.09097 
                 0.395797 
                 −1.45063 
                 2.964288 
                 −3.52209 
                 2.314678 
                 −0.64529 
               
               
                 S3 
                 0 
                 −0.04163 
                 0.200214 
                 −0.63045 
                 1.68779 
                 −2.44313 
                 2.013245 
                 −0.71923 
               
               
                 S4 
                 0 
                 0.221164 
                 −0.44254 
                 5.02223 
                 −23.3665 
                 66.00539 
                 −96.5244 
                 57.78121 
               
               
                 S5 
                 50.82239 
                 −0.02851 
                 1.221194 
                 −12.1101 
                 64.87433 
                 −197.804 
                 313.9412 
                 −205.553 
               
               
                 S6 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 S7 
                 0 
                 −0.14895 
                 −0.64199 
                 3.174452 
                 −4.72626 
                 −0.08198 
                 5.943744 
                 −3.70163 
               
               
                 S8 
                 0 
                 0.057288 
                 −0.43514 
                 1.089528 
                 −0.98837 
                 0.10879 
                 0.448187 
                 −0.21469 
               
               
                 S9 
                 −13.8144 
                 0.197387 
                 −0.36466 
                 0.38509 
                 −0.23848 
                 0.090741 
                 −0.01938 
                 0.001674 
               
               
                 S10 
                 −0.74756 
                 0.329506 
                 −0.48181 
                 0.538028 
                 −0.39467 
                 0.181283 
                 −0.04473 
                 0.004471 
               
               
                 S11 
                 0 
                 −0.1697 
                 −0.10039 
                 0.104605 
                 −0.05156 
                 0.011925 
                 −0.00046 
                 −0.00014 
               
               
                 S12 
                 −4.28179 
                 −0.07105 
                 −0.00668 
                 0.016414 
                 −0.0079 
                 0.001912 
                 −0.00024 
                  1.2E−05 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 11 . 
     Referring to  FIGS. 12 and 13 , according to a sixth embodiment of the present disclosure, a first optical imaging system  1  may include an optical system including a first lens  61 , a second lens  62 , a third lens  63 , a fourth lens  64 , a fifth lens  65 , and a sixth lens  66 , sequentially disposed from an object side, and may further include a filter  67  and an image sensor  68 . 
     The first lens  61  to the sixth lens  66  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  61  to the sixth lens  66  may be formed of a plastic material. 
     Table 12 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 12 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 −76.319 
                 0.300 
                 1.544 
                 56.1 
                 −2.296 
               
               
                 S2 
                   
                 1.277 
                 0.457 
               
               
                 S3 
                 Second lens 
                 2.07116 
                 0.438 
                 1.639 
                 23.5 
                 6.199 
               
               
                 S4 
                   
                 3.937 
                 0.455 
               
               
                 S5 
                 Third lens 
                 3.69064 
                 0.866 
                 1.544 
                 56.1 
                 1.996 
               
               
                 S6 
                   
                 −1.420 
                 0.104 
               
               
                 S7 
                 Fourth lens 
                 17.552 
                 0.364 
                 1.661 
                 20.35 
                 −5.530 
               
               
                 S8 
                   
                 3.029 
                 0.242 
               
               
                 S9 
                 Fifth lens 
                 −9.14891 
                 0.950 
                 1.544 
                 56.1 
                 2.168 
               
               
                 S10 
                   
                 −1.08759 
                 0.151 
               
               
                 S11 
                 Sixth lens 
                 1.941 
                 0.432 
                 1.614 
                 25.9 
                 −3.430 
               
               
                 S12 
                   
                 0.928 
                 0.418 
               
               
                 S13 
                 Filter 
                 Infinity 
                 0.110 
                 1.517 
                 64.2 
               
               
                 S14 
                   
                 Infinity 
                 0.716 
               
               
                 S15 
                 Imaging surface 
                 Infinity 
                 0.01446 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the first optical imaging system  1 , the total focal length F1 may be 1.8 mm, an angle of view (FOV1) may be 127.1°, Fno1 may be 2.17, TTL1 may be 6.018 mm, and BFL1 may be 1.259 mm. 
     In a sixth embodiment of the first optical imaging system  1 , the first lens  61  may have negative refractive power, and first and second surfaces of the first lens  61  may be concave in a paraxial region. 
     In addition, at least one inflection point may be formed on the first surface of the first lens  61 . For example, the first surface of the first lens  61  may be concave in a paraxial region and may be convex toward an edge. 
     The second lens  62  may have positive refractive power, a first surface of the second lens  62  may be convex in a paraxial region, and a second surface of the second lens  62  may be concave in the paraxial region. 
     The first lens  61  and the second lens  62  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  61  and the second lens  62  may be different from each other. 
     The third lens  63  may have positive refractive power, first and second surfaces of the third lens  63  may be convex in the paraxial region. 
     The second lens  62  and the third lens  63  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  62  and the third lens  63  may be different from each other. 
     A stop ST may be disposed between the second lens  62  and the third lens  63 . 
     The fourth lens  64  may have negative refractive power, a first surface of the fourth lens  64  may be convex in a paraxial region, and a second surface of the fourth lens  64  may be concave in the paraxial region. 
     The fifth lens  65  may have positive refractive power, a first surface of the fifth lens  65  may be concave in a paraxial region, and a second surface of the fifth lens  65  may be convex in the paraxial region. 
     The sixth lens  66  may have negative refractive power, a first surface of the sixth lens  66  may be convex, and a second surface of the sixth lens  66  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  66 . For example, the first surface of the sixth lens  66  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  66  may be concave in the paraxial region and may be convex toward the edge. 
     Meanwhile, the fifth lens  65  and the sixth lens  66  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the fifth lens  65  and the sixth lens  66  may be different from each other. In addition, the Abbe number of the sixth lens  66  may be 26 or less. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  61  to the sixth lens  66  may all be aspherical surfaces. For example, each surface of the first lens  61  to the sixth lens  66  may have an aspherical surface coefficient as shown in Table 13. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 0 
                 0.068509 
                 −0.03163 
                 0.013978 
                 −0.00417 
                 0.000691 
                 −4.7E−05 
                 0 
               
               
                 S2 
                 0 
                 −0.03209 
                 −0.01392 
                 0.174166 
                 −0.3508 
                 0.365799 
                 −0.13659 
                 0 
               
               
                 S3 
                 0 
                 −0.06331 
                 0.139087 
                 −0.03644 
                 0.104628 
                 −0.07923 
                 0 
                 0 
               
               
                 S4 
                 0 
                 0.112458 
                 0.02736 
                 0.780831 
                 −1.34047 
                 0.936652 
                 0 
                 0 
               
               
                 S5 
                 5.827832 
                 −0.04723 
                 0.411412 
                 −2.81044 
                 6.648248 
                 −5.55443 
                 −3.43272 
                 0 
               
               
                 S6 
                 1.481986 
                 −0.38011 
                 1.542717 
                 −3.5706 
                 5.197627 
                 −4.52795 
                 1.785504 
                 0 
               
               
                 S7 
                 0 
                 −0.7141 
                 1.581408 
                 −2.88402 
                 3.42128 
                 −2.62129 
                 0.84099 
                 0 
               
               
                 S8 
                 −11.3523 
                 −0.26206 
                 0.299755 
                 −0.18079 
                 0.046521 
                 0.001724 
                 −0.0024 
                 0 
               
               
                 S9 
                 −89.0846 
                 0.129618 
                 −0.28423 
                 0.296445 
                 −0.16288 
                 0.049159 
                 −0.00664 
                 0 
               
               
                 S10 
                 −0.71623 
                 0.241603 
                 −0.26091 
                 0.23643 
                 −0.13975 
                 0.049332 
                 −0.00707 
                 0 
               
               
                 S11 
                 0 
                 −0.257 
                 0.031918 
                 −0.02082 
                 0.02795 
                 −0.01658 
                 0.004655 
                 −0.0005 
               
               
                 S12 
                 −4.07704 
                 −0.11987 
                 0.034196 
                 −0.00521 
                 −0.00045 
                 0.000345 
                 −5.6E−05 
                 3.28E−06 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 13 . 
     Hereinafter, a second optical imaging system  2  will be described with reference to  FIGS. 14 to 20 . 
     The second optical imaging system  2  may satisfy at least one of the following conditional expressions. 
         Fno 2&lt;1.7  [Conditional Expression 17]
 
         TTL 2/Img H 2&lt;2.0  [Conditional Expression 18]
 
       70°≤FOV2  [Conditional Expression 19]
 
       −1.0&lt;( R 11_2+ R 12_2)/( R 11_2- R 12_2)&lt;1.0  [Conditional Expression 20]
 
       −1.0&lt;( R 9_2- R 10_2)/( R 9_2+ R 10_2)&lt;1.0  [Conditional Expression 21]
 
       35&lt; v 1_2− v 2_2  [Conditional Expression 22]
 
       −31&lt; v 3_2− v 4_2  [Conditional Expression 23]
 
       1.5&lt; Th 1_2/ Sag 1_2  [Conditional Expression 24]
 
       55&lt; v 7_2  [Conditional Expression 25]
 
       1.66 &lt;Nd 2_2  [Conditional Expression 26]
 
       1.65≤ Nd 5_2  [Conditional Expression 27]
 
       1.61&lt; Nd 6_2  [Conditional Expression 28]
 
       1.60&lt;( Nd 2_2+ Nd 5_2+ Nd 6_2)/3&lt;1.66  [Conditional Expression 29]
 
       1.59&lt;( Nd 2_2+ Nd 3_2+ Nd 4_2+ Nd 5_2+ Nd 6_2)/5&lt;1.61  [Conditional Expression 30]
 
       50&lt;| f 5_2/ F 2|  [Conditional Expression 31]
 
       50&lt;| f 6_2/ F 2|  [Conditional Expression 32]
 
     Fno2 may be a number (f-number) representing brightness of the second optical imaging system  2 , TTL2 may be a distance from an object side surface of a first lens of the second optical imaging system  2  to an imaging surface of an image sensor, F2 may be a total focal length of the second optical imaging system  2 , ImgH2 may be ½ of a diagonal length of the imaging surface of the image sensor of the second optical imaging system  2 , FOV2 may be an angle of view of the second optical imaging system  2 , R9_2 may be a radius of curvature of an object side surface of the fifth lens of the second optical imaging system  2 , R10_2 may be a radius of curvature of an image side surface of the fifth lens of the second optical imaging system  2 , R11_2 may be a radius of curvature of an object side surface of the sixth lens of the second optical imaging system  2 , R12_2 may be a radius of an image side surface of the sixth lens of the second optical imaging system  2 , v1_2 may be an Abbe number of the first lens of the second optical imaging system  2 , v2_2 may be an Abbe number of the second lens of the second optical imaging system  2 , v3_2 may be an Abbe number of the third lens of the second optical imaging system  2 , v4_2 may be an Abbe number of the fourth lens of the second optical imaging system  2 , v7_2 may be an Abbe number of the seventh lens of the second optical imaging system  2 , Th1_2 may be a center thickness of the first lens of the second optical imaging system  2 , Sag1_2 may be a distance in the optical axis direction from the end of an effective surface of the object side surface of the first lens of the second optical imaging system  2  to an apex of the effective surface of the object side surface of the first lens, Nd2_2 may be a refractive index of the second lens of the second optical imaging system  2 , Nd5_2 may be a refractive index of the fifth lens of the second optical imaging system  2 , Nd6_2 may be a refractive index of the sixth lens of the second optical imaging system  2 , f5_2 may be a focal length of the fifth lens of the second optical imaging system  2 , and f6_2 may be a focal length of the sixth lens of the second optical imaging system  2 . 
     Meanwhile, the effective surface may mean a portion in which light actually impinges on each surface of the lens. 
     Referring to  FIGS. 14 and 15 , according to a first embodiment of the present disclosure, the second optical imaging system  2  may include an optical system including a first lens  110 , a second lens  120 , a third lens  130 , a fourth lens  140 , a fifth lens  150 , a sixth lens  160  and a seventh lens  170  sequentially disposed from an object side, and may further include an infrared block filter  180  (hereinafter referred to as a ‘filter’) and an image sensor  190 . 
     The first lens  110  to the seventh lens  170  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  110  to the seventh lens  170  may be formed of a plastic material. 
     Table 14 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 14 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 or Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.8301 
                 0.7720 
                 1.544 
                 56.1 
                 4.470 
               
               
                 S2 
                   
                 6.2991 
                 0.1447 
               
               
                 S3 
                 Second lens 
                 8.2729 
                 0.2000 
                 1.661 
                 20.4 
                 −9.660 
               
               
                 S4 
                   
                 3.5691 
                 0.1696 
               
               
                 S5 
                 Third lens 
                 3.7311 
                 0.3337 
                 1.544 
                 56.1 
                 173.727 
               
               
                 S6 
                   
                 3.7620 
                 0.0470 
               
               
                 S7 
                 Fourth lens 
                 2.6622 
                 0.2300 
                 1.544 
                 56.1 
                 9.811 
               
               
                 S8 
                   
                 5.1500 
                 0.4686 
               
               
                 S9 
                 Fifth lens 
                 −1000.000 
                 0.3109 
                 1.661 
                 20.4 
                 12226873.6 
               
               
                 S10 
                   
                 −1000.000 
                 0.1970 
               
               
                 S11 
                 Sixth lens 
                 1000.000 
                 0.5668 
                 1.639 
                 23.5 
                 782.559 
               
               
                 S12 
                   
                 −1000.000 
                 0.1428 
               
               
                 S13 
                 Seventh lens 
                 1.6880 
                 0.5353 
                 1.534 
                 55.7 
                 −11.283 
               
               
                 S14 
                   
                 1.1730 
                 0.2666 
               
               
                 S15 
                 Filter 
                 Infinity 
                 0.1100 
                 1.518 
                 64.2 
               
               
                 S16 
                   
                 Infinity 
                 0.6800 
               
               
                 S17 
                 Imaging surface 
                 Infinity 
                 0.0100 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the second optical imaging system  2 , the total focal length F2 may be 4.3 mm, the angle of view FOV2 may be 76.72°, Fno2 may be 1.57, TTL2 may be 5.185 mm, and BFL2 may be 1.067 mm. 
     Here, BFL2 may be a distance from an image side surface of the seventh lens  170  to an imaging surface of the image sensor  190 . 
     In a first embodiment of the second optical imaging system  2 , the first lens  110  may have positive refractive power, a first surface of the first lens  110  may be convex in a paraxial region, and a second surface of the first lens  110  may be concave in the paraxial region. 
     The second lens  120  may have negative refractive power, a first surface of the second lens  120  may be convex in a paraxial region, and a second surface of the second lens  120  may be concave in the paraxial region. 
     The first lens  110  and the second lens  120  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  110  and the second lens  120  may be different from each other. 
     The third lens  130  may have positive refractive power, a first surface of the third lens  130  may be convex in a paraxial region, and a second surface of the third lens  130  may be concave in the paraxial region. 
     The second lens  120  and the third lens  130  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  120  and the third lens  130  may be different from each other. 
     A stop ST may be disposed between the second lens  120  and the third lens  130 . 
     The fourth lens  140  may have positive refractive power, a first surface of the fourth lens  140  may be convex in a paraxial region, and a second surface of the fourth lens  140  may be concave in the paraxial region. 
     The fifth lens  150  may have positive refractive power, a first surface of the fifth lens  150  may be concave in a paraxial region, and a second surface of the fifth lens  150  may be convex in the paraxial region. 
     The sixth lens  160  may have positive refractive power, first and second surfaces of the sixth lens  160  may be convex in a paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  160 . For example, the first surface of the sixth lens  160  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  160  may be convex in the paraxial region and may be concave toward the edge. 
     The seventh lens  170  may have negative refractive power, a first surface of the seventh lens  170  may be convex in a paraxial region, and a second surface of the seventh lens  170  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the seventh lens  170 . For example, the first surface of the seventh lens  170  may be convex in the paraxial region and may be concave toward an edge. The second surface of the seventh lens  170  may be concave in the paraxial region and may be convex toward the edge. 
     The second optical imaging system  2  may include a plurality of lenses having a high refractive index. For example, the second lens  120 , the fifth lens  150 , and the sixth lens  160  may have a refractive power of 1.6 or more. For example, the refractive index of the second lens  120  and the fifth lens  150  may be equal to or greater than 1.65 and less than 1.75, and the refractive index of the sixth lens  160  may be greater than 1.61. 
     The fifth lens  150  and the sixth lens  160  of the second optical imaging system  2  may have a considerably elongated focal length. For example, an absolute value of a focal length f5_2 of the fifth lens  150  and an absolute value of a focal length f6_2 of the sixth lens  160  may be 200 or more. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  110  to the seventh lens  170  may all be aspherical surfaces. For example, each surface of the first lens  110  to the seventh lens  170  may have an aspherical surface coefficient as shown in Table 15. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
                 J 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 −1.655 
                 0.012 
                 0.097 
                 −0.316 
                 0.610 
                 −0.741 
                 0.564 
                 −0.262 
                 0.068 
                 −0.007 
               
               
                 S2 
                 −24.000 
                 −0.013 
                 −0.036 
                 0.041 
                 −0.043 
                 0.043 
                 −0.036 
                 0.021 
                 −0.007 
                 0.001 
               
               
                 S3 
                 −50.687 
                 −0.039 
                 −0.031 
                 0.000 
                 0.220 
                 −0.442 
                 0.448 
                 −0.255 
                 0.079 
                 −0.010 
               
               
                 S4 
                 4.824 
                 −0.043 
                 −0.063 
                 0.151 
                 −0.383 
                 0.818 
                 −1.051 
                 0.767 
                 −0.288 
                 0.042 
               
               
                 S5 
                 −12.799 
                 −0.008 
                 0.162 
                 −0.939 
                 2.417 
                 −3.962 
                 4.125 
                 −2.590 
                 0.900 
                 −0.134 
               
               
                 S6 
                 −42.892 
                 −0.108 
                 0.317 
                 −0.851 
                 1.291 
                 −1.549 
                 1.597 
                 −1.138 
                 0.454 
                 −0.075 
               
               
                 S7 
                 −0.353 
                 −0.237 
                 0.581 
                 −1.663 
                 3.444 
                 −5.297 
                 5.688 
                 −3.834 
                 1.427 
                 −0.223 
               
               
                 S8 
                 −4.250 
                 −0.025 
                 −0.042 
                 0.311 
                 −1.013 
                 1.759 
                 −1.809 
                 1.126 
                 −0.397 
                 0.061 
               
               
                 S9 
                 0.000 
                 0.083 
                 −0.811 
                 2.302 
                 −4.184 
                 5.047 
                 −4.049 
                 2.072 
                 −0.610 
                 0.078 
               
               
                 S10 
                 0.000 
                 0.263 
                 −1.139 
                 2.072 
                 −2.444 
                 1.918 
                 −0.991 
                 0.323 
                 −0.060 
                 0.005 
               
               
                 S11 
                 0.000 
                 0.463 
                 −1.112 
                 1.591 
                 −1.606 
                 1.086 
                 −0.477 
                 0.130 
                 −0.020 
                 0.001 
               
               
                 S12 
                 0.000 
                 0.146 
                 −0.170 
                 0.112 
                 −0.063 
                 0.029 
                 −0.009 
                 0.002 
                 0.000 
                 0.000 
               
               
                 S13 
                 −10.824 
                 −0.201 
                 0.053 
                 0.010 
                 −0.009 
                 0.002 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
               
               
                 S14 
                 −5.597 
                 −0.136 
                 0.063 
                 −0.025 
                 0.008 
                 −0.001 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 15 . 
     Referring to  FIGS. 16 and 17 , according to a second embodiment of the present disclosure, a second optical imaging system  2  may include an optical system including a first lens  210 , a second lens  220 , a third lens  230 , a fourth lens  240 , a fifth lens  250 , a sixth lens  260  and a seventh lens  270 , and may further include an infrared block filter  280  (hereinafter referred to as a ‘filter’) and an image sensor  290 . 
     The first lens  210  to the seventh lens  270  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  210  to the seventh lens  270  may be formed of a plastic material. 
     Table 16 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 17 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.8308 
                 0.7752 
                 1.544 
                 56.1 
                 4.475 
               
               
                 S2 
                   
                 6.2824 
                 0.0847 
               
               
                 S3 
                 Second lens 
                 6.8610 
                 0.2000 
                 1.661 
                 20.4 
                 −9.598 
               
               
                 S4 
                   
                 3.2580 
                 0.1828 
               
               
                 S5 
                 Third lens 
                 3.2915 
                 0.3477 
                 1.544 
                 56.1 
                 55.807 
               
               
                 S6 
                   
                 3.5544 
                 0.0538 
               
               
                 S7 
                 Fourth lens 
                 2.8234 
                 0.2300 
                 1.544 
                 56.1 
                 11.039 
               
               
                 S8 
                   
                 5.1757 
                 0.4972 
               
               
                 S9 
                 Fifth lens 
                 −1000.000 
                 0.3274 
                 1.650 
                 21.5 
                 11926835.3 
               
               
                 S10 
                   
                 −1000.000 
                 0.1660 
               
               
                 S11 
                 Sixth lens 
                 1000.000 
                 0.5800 
                 1.614 
                 26.0 
                 814.422 
               
               
                 S12 
                   
                 −1000.000 
                 0.1257 
               
               
                 S13 
                 Seventh lens 
                 1.8210 
                 0.5750 
                 1.537 
                 55.7 
               
               
                 S14 
                   
                 1.2228 
                 0.2594 
               
               
                 S15 
                 Filter 
                 Infinity 
                 0.1100 
                 1.518 
                 64.2 
               
               
                 S16 
                   
                 Infinity 
                 0.6413 
               
               
                 S17 
                 Imaging surface 
                 Infinity 
                 0.0100 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the second optical imaging system  2 , the total focal length F2 may be 4.31 mm, the angle of view FOV2 may be 76.5°, Fno2 may be 1.57, TTL2 may be 5.166 mm, and BFL2 may be 1.021 mm. 
     In a second embodiment of the second optical imaging system  2 , a first surface of the first lens  210  may be convex in a paraxial region, and a second surface of the first lens  210  may be concave in the paraxial region. 
     The second lens  220  may have negative refractive power, the first surface of the second lens  220  may be convex in a paraxial region, and the second surface of the second lens  220  may be concave in the paraxial region. 
     The first lens  210  and the second lens  220  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  210  and the second lens  220  may be different from each other. 
     The third lens  230  may have positive refractive power, a first surface of the third lens  230  may be convex in a paraxial region, and a second surface of the third lens  230  may be concave in the paraxial region. 
     The second lens  220  and the third lens  230  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of second lens  220  and the third lens  230  may be different from each other. 
     A stop ST may be disposed between the second lens  220  and the third lens  230 . 
     The fourth lens  240  may have positive refractive power, a first surface of the fourth lens  240  may be convex in a paraxial region, and a second surface of the fourth lens  240  may be concave in the paraxial region. 
     The fifth lens  250  may have positive refractive power, a first surface of the fifth lens  250  may be concave in a paraxial region, and a second surface of the fifth lens  250  may be convex in the paraxial region. 
     The sixth lens  260  may have positive refractive power, and first and second surfaces of the sixth lens  260  may be convex in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  260 . For example, the first surface of the sixth lens  260  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  260  may be convex in the paraxial region and may be concave toward the edge. 
     The seventh lens  270  may have negative refractive power, a first surface of the seventh lens  270  may be convex in a paraxial region, and a second surface of the seventh lens  270  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the seventh lens  270 . For example, the first surface of the seventh lens  270  may be convex in the paraxial region and may be concave toward an edge. The second surface of the seventh lens  270  may be concave in the paraxial region and may be convex toward the edge. 
     The second optical imaging system  2  may have a plurality of lenses having a high refractive index. For example, the second lens  220 , the fifth lens  250  and the sixth lens  260  may have a refractive index of 1.6 or more. For example, the refractive indexes of the second lens  220  and the fifth lens  250  may be equal to or greater than 1.65 and less than 1.75, and the refractive index of the sixth lens  260  may be greater than 1.61. 
     In the second optical imaging system  2 , the fifth lens  250  and the sixth lens  260  may have a considerably elongated focal length. For example, an absolute value of a focal length f5_2 of the fifth lens  250  and an absolute value of a focal length f6_2 of the sixth lens  260  may be 200 or more. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  210  to the seventh lens  270  may all be aspherical surfaces. For example, each surface of the first lens  210  to the seventh lens  270  may have an aspherical surface coefficient as shown in Table 17. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 17 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
                 J 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 −1.656 
                 0.017 
                 0.061 
                 −0.191 
                 0.345 
                 −0.391 
                 0.276 
                 −0.118 
                 0.028 
                 −0.003 
               
               
                 S2 
                 −29.549 
                 0.024 
                 −0.175 
                 0.227 
                 −0.140 
                 0.013 
                 0.039 
                 −0.028 
                 0.008 
                 −0.001 
               
               
                 S3 
                 −31.058 
                 0.029 
                 −0.235 
                 0.236 
                 0.178 
                 −0.620 
                 0.643 
                 −0.346 
                 0.097 
                 −0.011 
               
               
                 S4 
                 4.285 
                 0.005 
                 −0.164 
                 0.036 
                 0.643 
                 −1.605 
                 2.015 
                 −1.469 
                 0.592 
                 −0.102 
               
               
                 S5 
                 −11.842 
                 0.013 
                 0.094 
                 −0.791 
                 2.300 
                 −4.209 
                 4.814 
                 −3.282 
                 1.228 
                 −0.195 
               
               
                 S6 
                 −43.654 
                 −0.082 
                 0.324 
                 −1.289 
                 3.146 
                 −5.876 
                 7.418 
                 −5.593 
                 2.264 
                 −0.380 
               
               
                 S7 
                 −0.420 
                 −0.223 
                 0.589 
                 −1.974 
                 5.123 
                 −9.881 
                 12.421 
                 −9.265 
                 3.709 
                 −0.615 
               
               
                 S8 
                 −2.376 
                 −0.029 
                 −0.064 
                 0.429 
                 −1.093 
                 1.409 
                 −1.004 
                 0.404 
                 −0.091 
                 0.011 
               
               
                 S9 
                 0.000 
                 0.107 
                 −1.122 
                 3.496 
                 −6.753 
                 8.525 
                 −7.072 
                 3.709 
                 −1.114 
                 0.146 
               
               
                 S10 
                 0.000 
                 0.397 
                 −1.761 
                 3.408 
                 −4.196 
                 3.399 
                 −1.796 
                 0.594 
                 −0.111 
                 0.009 
               
               
                 S11 
                 0.000 
                 0.623 
                 −1.600 
                 2.343 
                 −2.377 
                 1.623 
                 −0.724 
                 0.201 
                 −0.031 
                 0.002 
               
               
                 S12 
                 0.000 
                 0.220 
                 −0.272 
                 0.168 
                 −0.072 
                 0.023 
                 −0.005 
                 0.001 
                 0.000 
                 0.000 
               
               
                 S13 
                 −10.608 
                 −0.198 
                 0.077 
                 −0.012 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
               
               
                 S14 
                 −6.924 
                 −0.102 
                 0.029 
                 −0.005 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 17 . 
     Referring to  FIGS. 18 and 19 , according to a third embodiment of the present disclosure, a second optical imaging system  2  may include an optical system including a first lens  310 , a second lens  320 , a third lens  330 , a fourth lens  340 , a fifth lens  350 , a sixth lens  360  and a seventh lens  370 , sequentially disposed from an object side, and may further include an infrared block filter  380  (hereinafter referred to as a ‘filter’) and an image sensor  390 . 
     The first lens  310  to the seventh lens  370  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  310  to the seventh lens  370  may be formed of a plastic material. 
     Table 18 illustrates lens characteristics (a radius of curvature, a thickness of a lens, a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 18 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.842 
                 0.879 
                 1.544 
                 56.1 
                 3.999 
               
               
                 S2 
                   
                 9.986 
                 0.127 
               
               
                 S3 
                 Second lens 
                 13.514 
                 0.200 
                 1.661 
                 20.4 
                 −6.959 
               
               
                 S4 
                   
                 3.412 
                 0.182 
               
               
                 S5 
                 Third lens 
                 3.710 
                 0.291 
                 1.544 
                 56.1 
                 −223.645 
               
               
                 S6 
                   
                 3.501 
                 0.089 
               
               
                 S7 
                 Fourth lens 
                 2.601 
                 0.317 
                 1.544 
                 56.1 
                 7.552 
               
               
                 S8 
                   
                 6.781 
                 0.460 
               
               
                 S9 
                 Fifth lens 
                 −1000.000 
                 0.269 
                 1.650 
                 21.5 
                 14493820.8 
               
               
                 S10 
                   
                 −1000.000 
                 0.176 
               
               
                 S11 
                 Sixth lens 
                 1000.000 
                 0.597 
                 1.614 
                 26.0 
                 814.425 
               
               
                 S12 
                   
                 −1000.000 
                 0.076 
               
               
                 S13 
                 Seventh lens 
                 1.909 
                 0.505 
                 1.537 
                 55.7 
                 −9.34 
               
               
                 S14 
                   
                 1.255 
                 0.236 
               
               
                 S15 
                 Filter 
                 Infinity 
                 0.110 
                 1.518 
                 64.2 
               
               
                 S16 
                   
                 Infinity 
                 0.641 
               
               
                 S17 
                 Imaging surface 
                 Infinity 
                 0.010 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the second optical imaging system  2 , the total focal length F2 may be 4.29 mm, the angle of view FOV2 may be 76.46°, Fno2 may be 1.55, TTL2 may be 5.166 mm, and BFL2 may be 0.997 mm. 
     In a third embodiment of the second optical imaging system  2 , the first lens  310  may have positive refractive power, a first surface of the first lens  310  may be convex in a paraxial region, and a second surface of the first lens  310  may be concave in the paraxial region. 
     The second lens  320  may have negative refractive power, a first surface of the second lens  320  may be convex in a paraxial region, and a second surface of the second lens  320  may be concave in the paraxial region. 
     The first lens  310  and the second lens  320  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  310  and the second lens  320  may be different from each other. 
     The third lens  330  may have negative refractive power, a first surface of the third lens  330  may be convex in a paraxial region, and a second surface of the third lens  330  may be concave in the paraxial region. 
     The second lens  320  and the third lens  330  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  320  and the third lens  330  may be different from each other. 
     The fourth lens  340  may have positive refractive power, a first surface of the fourth lens  340  may be convex in a paraxial region, and a second surface of the fourth lens  340  may be concave in the paraxial region. 
     The fifth lens  350  may have positive refractive power, a first surface of the fifth lens  350  may be concave in a paraxial region, and a second surface of the fifth lens  350  may be convex in the paraxial region. 
     The sixth lens  360  may have positive refractive power, first and second surfaces of the sixth lens  360  may be convex in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  360 . For example, the first surface of the sixth lens  360  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  360  may be convex in the paraxial region and may be concave toward the edge. 
     The seventh lens  370  may have negative refractive power, a first surface of the seventh lens  370  may be convex in the paraxial region, and a second surface of the seventh lens  370  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the seventh lens  370 . For example, the first surface of the seventh lens  370  may be convex in the paraxial region and may be concave toward the edge. The second surface of the seventh lens  370  may be concave in the paraxial region and may be convex toward the edge. 
     The second optical imaging system  2  may include a plurality of lenses having a high refractive index. For example, the second lens  320 , the fifth lens  350  and the sixth lens  360  may have a refractive index of 1.6 or more. For example, the refractive indexes of the second lens  320  and the fifth lens  350  may be equal to or greater than 1.65 and less than 1.75, and the refractive index of the sixth lens  360  may be greater than 1.61. 
     In the second optical imaging system  2 , the fifth lens  350  and the sixth lens  360  may have a considerably elongated focal length. For example, an absolute value of a focal length f5_2 of the fifth lens  350  and an absolute value of a focal length f6_2 of the sixth lens  360  may be 200 or more. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  310  to the seventh lens  370  may all be aspherical surfaces. For example, each surface of the first lens  310  to the seventh lens  370  may have an aspherical surface coefficient as shown in Table 19. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 19 
               
               
                   
                   
               
               
                   
                 K 
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
                 H 
                 J 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 S1 
                 −1.462 
                 0.013 
                 0.061 
                 −0.172 
                 0.294 
                 −0.317 
                 0.216 
                 −0.090 
                 0.021 
                 −0.002 
               
               
                 S2 
                 −17.911 
                 −0.014 
                 −0.068 
                 0.144 
                 −0.186 
                 0.173 
                 −0.121 
                 0.058 
                 −0.016 
                 0.002 
               
               
                 S3 
                 −86.751 
                 −0.039 
                 −0.086 
                 0.224 
                 −0.222 
                 0.132 
                 −0.068 
                 0.039 
                 −0.015 
                 0.002 
               
               
                 S4 
                 4.714 
                 −0.039 
                 −0.046 
                 −0.031 
                 0.481 
                 −1.188 
                 1.542 
                 −1.167 
                 0.490 
                 −0.088 
               
               
                 S5 
                 −12.795 
                 −0.003 
                 0.041 
                 −0.082 
                 −0.210 
                 0.766 
                 −1.086 
                 0.789 
                 −0.273 
                 0.034 
               
               
                 S6 
                 −29.088 
                 −0.120 
                 0.394 
                 −1.126 
                 2.317 
                 −3.527 
                 3.656 
                 −2.421 
                 0.933 
                 −0.159 
               
               
                 S7 
                 −1.084 
                 −0.220 
                 0.409 
                 −1.013 
                 1.921 
                 −2.623 
                 2.393 
                 −1.384 
                 0.469 
                 −0.072 
               
               
                 S8 
                 −31.367 
                 −0.022 
                 −0.035 
                 0.002 
                 0.091 
                 −0.209 
                 0.203 
                 −0.091 
                 0.012 
                 0.002 
               
               
                 S9 
                 0.000 
                 0.126 
                 −0.931 
                 2.533 
                 −4.488 
                 5.319 
                 −4.223 
                 2.151 
                 −0.636 
                 0.083 
               
               
                 S10 
                 0.000 
                 0.366 
                 −1.533 
                 2.855 
                 −3.430 
                 2.735 
                 −1.430 
                 0.467 
                 −0.086 
                 0.007 
               
               
                 S11 
                 0.000 
                 0.527 
                 −1.377 
                 1.940 
                 −1.926 
                 1.304 
                 −0.578 
                 0.159 
                 −0.024 
                 0.002 
               
               
                 S12 
                 0.000 
                 0.243 
                 −0.388 
                 0.308 
                 −0.167 
                 0.065 
                 −0.018 
                 0.003 
                 0.000 
                 0.000 
               
               
                 S13 
                 −8.977 
                 −0.217 
                 0.056 
                 0.022 
                 −0.019 
                 0.006 
                 −0.001 
                 0.000 
                 0.000 
                 0.000 
               
               
                 S14 
                 −6.875 
                 −0.133 
                 0.049 
                 −0.010 
                 0.001 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
                 0.000 
               
               
                   
               
            
           
         
       
     
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 19 . 
     Table 20 shows conditional expression values of the second optical imaging system  2  according to each embodiment. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 20 
               
               
                   
                   
               
               
                   
                 First 
                 Second 
                 Third 
               
               
                   
                 embodiment of 
                 embodiment of 
                 embodiment of 
               
               
                   
                 second optical 
                 second optical 
                 second optical 
               
               
                   
                 imaging system 
                 imaging system 
                 imaging system 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Fno 
                 1.57 
                 1.57 
                 1.55 
               
               
                 TTL/ImgH2 
                 1.48 
                 1.48 
                 1.48 
               
               
                 F2 
                 4.30 
                 4.31 
                 4.29 
               
               
                 FOV2 
                 76.72 
                 76.50 
                 76.46 
               
               
                 (R12_2 + R13_2)/ 
                 0.00 
                 0.00 
                 0.00 
               
               
                 (R12_2 − R13_2) 
               
               
                 (R8_2 − R9_2)/ 
                 0.00 
                 0.00 
                 0.00 
               
               
                 (R8_2 + R9_2) 
               
               
                 v1_2 − v2_2 
                 35.74 
                 35.74 
                 35.74 
               
               
                 v3_2 − v4_2 
                 0.00 
                 0.00 
                 −30.14 
               
               
                 Th1_2/Sag1_2 
                 1.54 
                 1.53 
                 1.61 
               
               
                 v7_2 
                 55.66 
                 55.66 
                 55.66 
               
               
                 Nd2_2 
                 1.66 
                 1.66 
                 1.66 
               
               
                 Nd5_2 
                 1.66 
                 1.65 
                 1.65 
               
               
                 Nd6_2 
                 1.64 
                 1.61 
                 1.61 
               
               
                   
               
            
           
         
       
     
     Hereinafter, a third optical imaging system  3  will be described with reference to  FIGS. 21 to 29 . 
     The third optical imaging system  3  may satisfy at least one of the following conditional expressions. 
       0.7&lt; TTL 3/ F 3&lt;1.0  [Conditional Expression 33]
 
       0.15&lt; R 1_3/ F 3&lt;0.32  [Conditional Expression 34]
 
       −3.5&lt; F 3/ f 2_3&lt;−0.5  [Conditional Expression 35]
 
       0.1&lt; d 45_3/ TTL 3&lt;0.7  [Conditional Expression 36]
 
       1.6&lt; Nd 6_3&lt;1.75  [Conditional Expression 37]
 
       0.3&lt;tan θ_3&lt;0.5  [Conditional Expression 38]
 
       2.0&lt; Fno 3&lt;2.7  [Conditional Expression 39]
 
     TTL3 may be a distance from an object side surface of the first lens of the third optical imaging system  3  to an imaging surface of the image sensor, F3 may be the total focal length of the third optical imaging system  3 , f2_3 may be a focal length of the second lens of the third optical imaging system  3 , R1_3 may be the radius of curvature of the object side surface of the first lens of the third optical imaging system  3 , d45_3 may be a distance from the image side surface of the fourth lens of the third optical imaging system  3  to the object side surface of the fifth lens, Nd6_3 may be a refractive index of the sixth lens of the third optical imaging system  3 , θ_3 may be the half angle of view of the third optical imaging system  3 , and Fno3 may be a number (f-number) representing brightness of the third optical imaging system  3 . 
     The conditional expression 33 may be a condition for miniaturizing the third optical imaging system  3 . For example, when an upper limit value of the conditional expression 33 is exceeded, it is difficult to be miniaturized, and thus is difficult to be mounted on portable electronic devices, and when a lower limit value of the conditional expression 33 is exceeded, it is difficult to be manufactured. 
     The conditional expression 34 may be a condition for manufacturing a first lens for constructing the angle of view of the third optical imaging system  3  to be relatively narrow. For example, the first lens, which exceeds the upper limit value of the conditional expression 34, may increase longitudinal spherical aberration and shorten the focal length of the third optical imaging system  3 , and the first lens, which exceeds the lower limit value of the conditional expression 34, may increase the focal length of the third optical imaging system  3 , but the lens may be difficult to be manufactured. Further, the first lens, which exceeds the lower limit value of the conditional expression 34, may have a thinner thickness in a lens edge portion, making it difficult to be manufactured. 
     The conditional expression 35 may be a design condition of the second lens for realizing high resolution. For example, the second lens, which exceeds a numerical value of the conditional expression 35, may increase astigmatism of the third optical imaging system  3  to cause image deterioration. 
     Conditional expression 36 may be a design condition for constructing the angle of view of the third optical imaging system  3  to be relatively narrow. For example, when the lower limit value of the conditional expression 35 is exceeded, the focal length may be short and it is difficult to use for telephoto. When the upper limit value of the conditional expression 36 is exceeded, the total focal length TTL of the third optical imaging system  3  may become large and it is difficult to be miniaturized. 
     Conditional expression 37 may be a design condition of the sixth lens for realizing high resolution. For example, the sixth lens satisfying the numerical range of the conditional expression 37 may have a low Abbe number of 26 or less, such that it is advantageous in correcting astigmatism, longitudinal chromatic aberration, and magnification aberration. 
     Conditional expression 38 may be the angle of view of the third optical imaging system  3 , and conditional expression 39 may be a numerical range of Fno3 for realizing high resolution. 
     In the third optical imaging system  3 , the refractive power of the lens (the reciprocal of the absolute value of the focal length) may be disposed in a predetermined order. As an example, the refractive power of the odd-numbered lens may be greater than the refractive power of the even-numbered lens disposed on the image side. For example, the refractive power of the first lens may be greater than the refractive power of the second lens, the refractive power of the third lens may be greater than the refractive power of the fourth lens, and the refractive power of the fifth lens may be greater than the refractive power of the sixth lens. 
     In the third optical imaging system, a lens having the largest refractive power may be disposed close to an object side, a lens having the smallest refractive power may be disposed close to an image side. For example, the first lens of the third optical imaging system  3  may have the largest refractive power, and the fourth lens or the sixth lens may have the smallest refractive power. 
     In the third optical imaging system  3 , the first lens may have the most convex surface. For example, the object side surface of the first lens may be the most convex surface among the surfaces of each lens. In the third optical imaging system  3 , the second lens may have the most concave surface. For example, the image side surface of the second lens may be the most concave surface. In the third optical imaging system  3 , the fourth lens may have a generally flat surface. For example, the image side surface of the fourth lens may be a shape close to a plane. 
     In the third optical imaging system  3 , three or more lenses adjacent to each other may have substantially similar refractive indexes. For example, the second lens to the fourth lens may have substantially the same or similar refractive index. The refractive index of the second lens to the fourth lens may be selected in the range of 1.63 to 1.68. 
     Referring to  FIGS. 21 to 23 , according to a first embodiment of the present disclosure, a third optical imaging system  3  may include an optical system including a first lens  1100 , a second lens  1200 , a third lens  1300 , a fourth lens  1400 , a fifth lens  1500 , and a sixth lens  1600 , sequentially disposed from an object side, and may further include an infrared block filter  1700  (hereinafter, referred to as a ‘filter’) and an image sensor  1800 . 
     The first lens  1100  to the sixth lens  1600  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis. The first lens  1100  to the sixth lens  1600  may be formed of a plastic material. 
     Table 21 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 21 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.5100 
                 0.9130 
                 1.544 
                 56.1 
                 2.750 
               
               
                 S2 
                   
                 −323.8700 
                 0.1300 
               
               
                 S3 
                 Second lens 
                 6.2200 
                 0.2400 
                 1.661 
                 20.3 
                 −6.460 
               
               
                 S4 
                   
                 2.5100 
                 0.3320 
               
               
                 S5 
                 Third lens 
                 −7.1600 
                 0.2400 
                 1.650 
                 21.5 
                 −4.260 
               
               
                 S6 
                   
                 4.6600 
                 0.0500 
               
               
                 S7 
                 Stop 
                 Infinity 
                 0.0100 
               
               
                 S8 
                 Fourth lens 
                 4.6400 
                 0.2400 
                 1.650 
                 21.5 
                 6.900 
               
               
                 S9 
                   
                 −200.0000 
                 1.2210 
               
               
                 S10 
                 Fifth lens 
                 −2.730 
                 0.2900 
                 1.544 
                 56.1 
                 −4.230 
               
               
                 S11 
                   
                 15.730 
                 0.1500 
               
               
                 S12 
                 Sixth lens 
                 17.180 
                 0.6980 
                 1.650 
                 21.5 
                 10.310 
               
               
                 S13 
                   
                 −11.010 
                 0.5000 
               
               
                 S14 
                 Filter 
                 Infinity 
                 0.1100 
                 1.523 
                 39.1 
               
               
                 S15 
                   
                 Infinity 
                 0.2670 
               
               
                 S16 
                 Imaging surface 
                 Infinity 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the third optical imaging system  3 , the total focal length F3 may be 5.997 mm, the angle of view FOV3 may be 47.594°, Fno3 may be 2.48, TTL3 may be 5.391 mm, and BFL3 may be 0.877 mm. 
     BFL3 may be a distance from an image side surface of the sixth lens  160  to an imaging surface of the image sensor  180 . 
     In a first embodiment of the third optical imaging system  3 , the first lens  1100  may have positive refractive power, first and second surfaces of the first lens  1100  may be convex in a paraxial region. 
     The second lens  1200  may have negative refractive power, a first surface of the second lens  1200  may be convex in a paraxial region, and a second surface of the second lens  1200  may be concave in the paraxial region. 
     The first lens  1100  and the second lens  1200  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  1100  and the second lens  1200  may be different from each other. 
     The third lens  1300  may have negative refractive power, first and second surfaces of the third lens  1300  may be concave in the paraxial region. 
     The second lens  1200  and the third lens  1300  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe numbers of the second lens  1200  and the third lens  1300  may be different from each other. 
     The fourth lens  1400  may have positive refractive power, first and second surfaces of the fourth lens  1400  may be convex in the paraxial region. 
     A stop ST may be disposed between the third lens  1300  and the fourth lens  1400 . 
     The fifth lens  1500  may have negative refractive power, first and second surfaces of the fifth lens  1500  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the fifth lens  1500 . For example, the first surface of the fifth lens  1500  may be concave in the paraxial region and may be convex toward an edge. The second surface of the fifth lens  1500  may be concave in the paraxial region and may be convex toward the edge. 
     The sixth lens  1600  may have positive refractive power, first and second surfaces of the sixth lens  1600  may be convex in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  1600 . For example, the first surface of the sixth lens  1600  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  1600  may be convex in the paraxial region and may be concave toward the edge. 
     Among the first lens  1100  to the sixth lens  1600 , the absolute value of the focal length of the first lens  1100  may be the smallest, and the absolute value of the focal length of the sixth lens  1600  may be the largest. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  1100  to the sixth lens  1600  may all be aspherical surfaces. For example, each surface of the first lens  1100  to the sixth lens  1600  may have an aspherical surface coefficient as shown in  FIG. 22 . 
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 23 . 
     Referring to  FIGS. 24 to 26 , according to a second embodiment of the present disclosure, a third optical imaging system  3  may include an optical system including a first lens  2100 , a second lens  2200 , a third lens  2300 , a fourth lens  2400 , a fifth lens  2500 , and a sixth lens  2600 , sequentially disposed from an object side, and may further include an infrared block filter  2700  (hereinafter, referred to as a ‘filter’) and an image sensor  2800 . 
     The first lens  2100  to the sixth lens  2600  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  2100  to the sixth lens  2600  may be formed of a plastic material. 
     Table 22 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 22 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.5100 
                 0.9090 
                 1.544 
                 56.1 
                 2.760 
               
               
                 S2 
                   
                 −4974.2600 
                 0.1210 
               
               
                 S3 
                 Second lens 
                 6.6100 
                 0.2400 
                 1.661 
                 20.3 
                 −6.960 
               
               
                 S4 
                   
                 2.6900 
                 0.3430 
               
               
                 S5 
                 Third lens 
                 −5.1000 
                 0.2400 
                 1.650 
                 21.5 
                 −5.300 
               
               
                 S6 
                   
                 11.2400 
                 0.0180 
               
               
                 S7 
                 Stop 
                 Infinity 
                 0.0700 
               
               
                 S8 
                 Fourth lens 
                 6.9800 
                 0.2400 
                 1.650 
                 21.5 
                 10.590 
               
               
                 S9 
                   
                 −2000.0000 
                 1.2040 
               
               
                 S10 
                 Fifth lens 
                 −2.990 
                 0.2900 
                 1.544 
                 56.1 
                 −4.230 
               
               
                 S11 
                   
                 10.600 
                 0.1290 
               
               
                 S12 
                 Sixth lens 
                 17.560 
                 0.7090 
                 1.650 
                 21.5 
                 11.500 
               
               
                 S13 
                   
                 −13.0700 
                 0.5000 
               
               
                 S14 
                 Filter 
                 Infinity 
                 0.1100 
                 1.523 
                 39.1 
               
               
                 S15 
                   
                 Infinity 
                 0.2660 
               
               
                 S16 
                 Imaging surface 
                 Infinity 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the third optical imaging system  3 , the total focal length F3 may be 6.001 mm, the angle of view (FOV3) may be 47.594°, Fno3 may be 2.488, TTL3 may be 5.389 mm, and BFL3 may be 0.876 mm. 
     In a second embodiment of the third optical imaging system  3 , the first lens  2100  may have positive refractive power, first and second surfaces of the first lens  2100  may be convex in a paraxial region. 
     The second lens  2200  may have negative refractive power, a first surface of the second lens  2200  may be convex in a paraxial region, and a second surface of the second lens  2200  may be concave in the paraxial region. 
     The first lens  2100  and the second lens  2200  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  2100  and the second lens  2200  may be different from each other. 
     The third lens  2400  may have negative refractive power, and first and second surfaces of the third lens  2300  may be concave in the paraxial region. 
     The second lens  2200  and the third lens  2300  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  2200  and the third lens  2300  may be different from each other. 
     The fourth lens  2400  may have positive refractive power, and first and second surfaces of the fourth lens  2400  may be convex in the paraxial region. 
     A stop ST may be disposed between the third lens  2300  and the fourth lens  2400 . 
     The fifth lens  2500  may have negative refractive power, first and second surfaces of the fifth lens  2500  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the fifth lens  2500 . For example, the first surface of the fifth lens  2500  may be concave in the paraxial region and may be convex toward an edge. The second surface of the fifth lens  2500  may be concave in the paraxial region and may be convex toward the edge. 
     The sixth lens  2600  may have positive refractive power, and first and second surfaces of the sixth surface  2600  may be convex in a paraxial region. 
     At least one inflection point may be formed on the first and second surfaces of the sixth lens  2600 . For example, the first surface of the sixth lens  2600  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  2600  may be convex in the paraxial region and may be concave toward the edge. 
     Among the first lens  2100  to the sixth lens  2600 , the absolute value of the focal length of the first lens  2100  may be the smallest, and the absolute value of the focal length of the sixth lens  2600  may be the largest. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  2100  to the sixth lens  2600  may all be aspherical surfaces. For example, each surface of the first lens  2100  to the sixth lens  2600  may have an aspherical surface coefficient as shown in  FIG. 25 . 
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 26 . 
     Referring to  FIGS. 27 to 29 , according to a third embodiment of the present disclosure, a third optical imaging system  3  may include an optical system including a first lens  3100 , a second lens  3200 , a third lens  3300 , a fourth lens  3400 , a fifth lens  3500 , and a sixth lens  3600 , sequentially disposed from an object side, and may further include an infrared block filter  3700  (hereinafter, referred to as a ‘filter’) and an image sensor  3800 . 
     The first lens  3100  to the sixth lens  3600  may be disposed to be spaced apart from each other by a predetermined distance along an optical axis, respectively. The first lens  3100  to the sixth lens  3600  may be formed of a plastic material. 
     Table 23 illustrates lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 23 
               
               
                   
               
               
                 Surface 
                   
                 Radius of 
                 Thickness or 
                 Refractive 
                 Abbe 
                 Focal 
               
               
                 number 
                 Reference 
                 curvature 
                 Distance 
                 index 
                 number 
                 length 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S1 
                 First lens 
                 1.4900 
                 0.891 
                 1.544 
                 56.1 
                 2.770 
               
               
                 S2 
                   
                 65.7500 
                 0.121 
               
               
                 S3 
                 Second lens 
                 13.0600 
                 0.240 
                 1.661 
                 20.3 
                 −7.690 
               
               
                 S4 
                   
                 3.6600 
                 0.301 
               
               
                 S5 
                 Third lens 
                 −4.9600 
                 0.240 
                 1.650 
                 21.5 
                 −10.43 
               
               
                 S6 
                   
                 −18.2300 
                 0.007 
               
               
                 S7 
                 Stop 
                 Infinity 
                 0.100 
               
               
                 S8 
                 Fourth lens 
                 20000.0 
                 0.240 
                 1.650 
                 21.5 
                 −18899.98 
               
               
                 S9 
                   
                 7663.75 
                 1.182 
               
               
                 S10 
                 Fifth lens 
                 −3.1200 
                 0.290 
                 1.544 
                 56.1 
                 −4.25 
               
               
                 S11 
                   
                 9.3600 
                 0.189 
               
               
                 S12 
                 Sixth lens 
                 18.6100 
                 0.713 
                 1.650 
                 21.5 
                 12.03 
               
               
                 S13 
                   
                 −13.5400 
                 0.500 
               
               
                 S14 
                 Filter 
                 Infinity 
                 0.110 
                 1.523 
                 39.1 
               
               
                 S15 
                   
                 Infinity 
                 0.271 
               
               
                 S16 
                 Imaging surface 
                 Infinity 
               
               
                   
               
            
           
         
       
     
     Meanwhile, in the third optical imaging system  3 , the total focal length F3 may be 6.001 mm, the angle of view (FOV3) may be 47.594°, Fno3 may be 2.59, TTL3 may be 5.395 mm, and BFL3 may be 0.881 mm. 
     In the third embodiment of the third optical imaging system  3 , the first lens  3100  may have positive refractive power, a first surface of the first lens  3100  may be convex in a paraxial region, and a second surface of the first lens  3100  may be concave in the paraxial region. 
     The second lens  3200  may have negative refractive power, a first surface of the second lens  3200  may be convex in a paraxial region, and a second surface of the second lens  3200  may be concave in the paraxial region. 
     The first lens  3100  and the second lens  3200  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the first lens  3100  and the second lens  3200  may be different from each other. 
     The third lens  3300  may have negative refractive power, a first surface of the third lens  3300  may be concave in a paraxial region, and a second surface of the third lens  3300  may be convex in the paraxial region. 
     The second lens  3200  and the third lens  3300  may be formed of plastic materials having different optical characteristics from each other. As an example, the Abbe number of the second lens  3200  and the third lens  3300  may be different from each other. 
     The fourth lens  3400  may have negative refractive power, and a first surface of the fourth lens  3400  may be convex in a paraxial region, and a second surface of the fourth lens  3400  may be concave in the paraxial region. 
     A stop ST may be disposed between the third lens  3300  and the fourth lens  3400 . 
     The fifth lens  3500  may have negative refractive power, and first and second surfaces of the fifth lens  3500  may be concave in the paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the fifth lens  3500 . For example, the first surface of the fifth lens  3500  may be concave in the paraxial region and may be convex toward an edge. The second surface of the fifth lens  3500  may be concave in the paraxial region and may be convex toward the edge. 
     The sixth lens  3600  may have positive refractive power, first and second surfaces of the sixth lens  3600  may be convex in a paraxial region. 
     In addition, at least one inflection point may be formed on the first and second surfaces of the sixth lens  3600 . For example, the first surface of the sixth lens  3600  may be convex in the paraxial region and may be concave toward an edge. The second surface of the sixth lens  3600  may be convex in the paraxial region and may be concave toward the edge. 
     Among the first lens  3100  to the sixth lens  3600 , the absolute value of the focal length of the first lens  3100  may be the smallest, and the absolute value of the focal length of the fourth lens  3400  may be the largest. 
     Meanwhile, object side surfaces and image side surfaces of the first lens  3100  to the sixth lens  3600  may all be aspherical surfaces. For example, each surface of the first lens  3100  to the sixth lens  3600  may have an aspherical surface coefficient as shown in  FIG. 28 . 
     In addition, the optical imaging system thus configured may have aberration characteristics illustrated in  FIG. 29 . 
     Table 24 shows conditional expression values of the third optical imaging system  3  according to each embodiment. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 24 
               
               
                   
                   
               
               
                   
                 First 
                 Second 
                 Third 
               
               
                   
                 embodiment of 
                 embodiment of 
                 embodiment of 
               
               
                   
                 third optical 
                 third optical 
                 third optical 
               
               
                   
                 imaging system 
                 imaging system 
                 imaging system 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 TTL3/F3 
                 0.899 
                 0.898 
                 0.899 
               
               
                 R1_3/F3 
                 0.251 
                 0.252 
                 0.248 
               
               
                 F3/f2_3 
                 −0.928 
                 −0.862 
                 −0.781 
               
               
                 d45_3/TTL3 
                 0.226 
                 0.223 
                 0.219 
               
               
                 Nd6_3 
                 1.65 
                 1.65 
                 2.65 
               
               
                 tanθ_3 
                 0.441 
                 0.441 
                 0.441 
               
               
                 Fno3 
                 2.48 
                 2.488 
                 2.59 
               
               
                   
               
            
           
         
       
     
     As set forth above, according to an embodiment of the present disclosure, a subject may be captured at various distances. 
     While specific examples have been shown and described above, it will be apparent after an understanding of the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.