Patent Publication Number: US-2019179126-A1

Title: Lens

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims benefit of priority to Korean Patent Application No. 10-2017-0170635 filed on Dec. 12, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a lens for a camera configured to reduce a flare phenomenon. 
     2. Description of Related Art 
     When an object is imaged by a camera, light incident at an unspecified angle may cause reflections in a lens, and a flare phenomenon, causing problems in an image. A flare phenomenon may be reduced using an aperture disposed between lenses, but a flare phenomenon may not be completely removed. Also, an aperture may significantly reduce the amount of light incident through a lens, which may lead to reduction in relative illumination (RI). 
     Thus, it may be necessary to develop a lens which can reduce a flare phenomenon without reducing relative illumination. 
     SUMMARY 
     An aspect of the present disclosure is to provide a lens configured to reduce a flare phenomenon. 
     According to an aspect of the present disclosure, a lens includes a refractive portion refracting incident light, a flange portion disposed at an edge of the refractive portion, and a light shielding portion shielding incident light and extending from the flange portion towards the refractive portion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional diagram illustrating a lens according to an exemplary embodiment in the present disclosure; 
         FIG. 2  is a cross-sectional diagram illustrating a combined lens assembly including a lens in  FIG. 1 ; 
         FIG. 3  is a cross-sectional diagram illustrating a lens according to another exemplary embodiment in the present disclosure; and 
         FIG. 4  is a cross-sectional diagram illustrating a lens according to another exemplary embodiment in the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described as follows with reference to the attached drawings. 
     With respect to terms used in exemplary embodiments, the terms are selected in view of a function of each element, and the terms used in the description are not to be taken in a limiting sense. 
     In the exemplary embodiments, when an element is mentioned as being “connected” to another component, this may mean that the element is directly connected to another component, and may also mean that the element is indirectly connected to another component with an intervening element therebetween. Also, it will be understood that when a portion “includes” an element, it may further include another element, not excluding another element, unless otherwise indicated. 
     In the description below, a lens according to an exemplary embodiment will be described with reference to  FIG. 1 . 
     A lens  10  according to the exemplary embodiment may include a refractive portion  100 , a flange portion  200 , and a light shielding portion  300 . 
     The refractive portion  100  may pass and refract light. For example, the refractive portion  100  may have a concave surface or a convex surface in the lens  10 . By the refractive portion  100  configured as above, the lens  10  may have positive refractive force or negative refractive force. The refractive portion  100  may include a valid region  110  and an invalid region  120 . For example, with reference to an optical center (C-C), an overall area of the refractive portion  100  may be the valid region  110  configured as an aspheric surface, and the rest of the area of the refractive portion  100  may be the invalid region  120  configured to not refract light. In the exemplary embodiment, the invalid region  120  may be formed on an edge of the valid region  110 . 
     The flange portion  200  may be configured to not pass or refract light. For example, the flange portion  200  may be a planar portion in the lens  10 . However, the flange portion  200  may not be exactly planar. For instance, the flange portion  200  may include a protrusion, a groove, a stepped portion, and the like, to be coupled to an adjacent lens. The flange portion  200  configured as above may be disposed at an edge of the refractive portion  100 , and by the flange portion  200 , the lens  10  may be properly disposed, and the lenses may be properly combined. 
     The light shielding portion  300  may shield light incident at an unspecified angle. For example, the light shielding portion  300  may be disposed at the flange portion  200  which does not refract light, and may be disposed in the refractive portion  100  to reduce a flare phenomenon caused by internal reflections in the lens  10 . The light shielding portion  300  may be, for example, disposed to include an overall boundary area between the refractive portion  100  and the flange portion  200 . 
     The light shielding portion  300  may be divided into a first light shielding portion  310  and a second light shielding portion  320  in accordance with locations in which the light shielding portion  300  is formed. For example, the first light shielding portion  310  may be disposed in the flange portion  200 , and the second light shielding portion  320  may be disposed to be in contact with the refractive portion  100 . The first light shielding portion  310  may entirely cover one surface of the flange portion  200 . The first light shielding portion  310  configured as above may shield unnecessary light incident through the flange portion  200  effectively. The second light shielding portion  320  may be disposed to cover the invalid region  120  in the refractive portion  100 . For example, the second light shielding portion  320  may cover an overall area of the invalid region  120  except for the valid region  110  in the refractive portion  100 . Accordingly, a length L of the second light shielding portion  320  may satisfy an equation as below. 
       0.2≤ L /( D max−DED)≤1.0  [Equation]
 
     Here, “Dmax” may be a maximum diameter of the refractive portion  100 , and “DED” may be a maximum diameter of the valid region  110 . 
     The light shielding portion  300  may be manufactured using a solid material including a light shielding material, or a liquid material including a light shielding material. If the light shielding portion  300  is formed of a solid material, the light shielding portion  300  may be attached to the refractive portion  100  and the flange portion  200  through an adhesion process, a fusion process, or the like, and if the light shielding portion  300  is formed of a liquid material, the light shielding portion  300  may be disposed in the refractive portion  100  and the flange portion  200  by a printing method, and the like. The light shielding portion  300  may have a certain thickness in both examples above, and a member for maintaining a gap disposed between the lenses may thus be omitted. 
     In the description below, a lens assembly including a lens according to an exemplary embodiment will be described with reference to  FIG. 2 . 
     The lens  10  in the exemplary embodiment may be implemented by any lens included in the lens assembly  1000 . For example, the lens  10  may be disposed between a lens  20  and a lens  60 . As another example, in the lens assembly  1000 , the lens  10  may be disposed most closely to an object. As yet another example, the lens  10  may be disposed most closely to a top surface (an imaging plane) in the lens assembly  1000 . In any examples above, the lens  10  may shield light incident at an unspecified angle and reduce a flare phenomenon. 
     Table 1 below relates to a comparison between a general lens and a lens having a light shield portion. As indicated in Table 1 below, a general lens has a significantly high density of flare formed by light incident at an unspecified angle. However, the lens satisfying the aforementioned equation (embodiments 3 to 7) has a significantly reduced flare density. Meanwhile, “relative illumination” in Table 1 is a percentage ratio (%) of the amount of light incident to a lens when an aperture is not present. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 L/(Dmax − 
                 Flare Density 
                 Relative 
               
               
                   
                 DED)*100(%) 
                 (10 −14  W) 
                 Illumination (%) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Comparative 
                  0% 
                 33100 
                 100% 
               
               
                 Example 
               
               
                 Embodiment 1 
                  8% 
                 32600 
                 100% 
               
               
                 Embodiment 2 
                 15% 
                 26200 
                 100% 
               
               
                 Embodiment 3 
                 23% 
                 10400 
                 100% 
               
               
                 Embodiment 4 
                 30% 
                 7.97 
                 100% 
               
               
                 Embodiment 5 
                 38% 
                 4.33 
                 100% 
               
               
                 Embodiment 6 
                 45% 
                 3.29 
                 100% 
               
               
                 Embodiment 7 
                 100%  
                 2.96 
                 100% 
               
               
                   
               
            
           
         
       
     
     In the description below, a lens according to another example embodiment will be described. The same elements described in the aforementioned exemplary embodiments will be indicated by the same reference numerals, and the detailed descriptions of the same elements will not be repeated. 
     A lens according to another exemplary embodiment will be described with reference to  FIG. 3 . 
     A lens  12  according to the exemplary embodiment may include a protrusion  210  as illustrated in  FIG. 3 . The protrusion  210  may be disposed in a flange portion  200 , and may work as a means to couple the lens to an adjacent lens. 
     In the exemplary embodiment, a light shielding portion  300  may be disposed in the flange portion  200  and the protrusion  210 . More specifically, the light shielding portion  300  may be disposed on one side portion of the protrusion  210  and a circumferential surface  220  of the flange portion  200 . 
     The lens  12  configured as above may effectively reduce a flare phenomenon caused by internal reflections in a lens barrel. 
     In the description below, a lens according to another exemplary embodiment will be described with reference to  FIG. 4 . 
     A lens  14  according to the exemplary embodiment may be different from the lens  10  in the aforementioned exemplary embodiment in that, in the lens  14 , the light shielding portion  300  is disposed on both surfaces of the lens  14 . 
     The light shielding portion  300  may be formed on one surface (a surface close to an object) of the lens  14  and on the other surface (a surface close to an upper surface) in different forms. For example, on one surface of the lens  14 , a first light shielding portion  310  and a second light shielding portion  320  may be formed in the flange portion  200  and the refractive portion  100 , respectively, and on the other surface of the lens  14 , the light shielding portion  300  may only be formed in the flange portion  200 . 
     According to the aforementioned exemplary embodiments, a flare phenomenon caused by light incident at an unspecified angle may be reduced. 
     Further, the lens in the exemplary embodiments may not need a separate light shielding member and a separate gap maintaining member. Accordingly, a weight of a camera module including a plurality of lenses may be significantly reduced. 
     While the exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.