Patent Publication Number: US-10775589-B2

Title: Camera optical lens

Description:
FIELD OF THE PRESENT DISCLOSURE 
     The present disclosure relates to optical lens, in particular to a camera optical lens suitable for handheld devices such as smart phones and digital cameras and imaging devices. 
     DESCRIPTION OF RELATED ART 
     With the emergence of smart phones in recent years, the demand for miniature camera lens is increasing day by day, but the photosensitive devices of general camera lens are no other than Charge Coupled Device (CCD) or Complementary metal-Oxide Semiconductor Sensor (CMOS sensor), and as the progress of the semiconductor manufacturing technology makes the pixel size of the photosensitive devices shrink, coupled with the current development trend of electronic products being that their functions should be better and their shape should be thin and small, miniature camera lens with good imaging quality therefor has become a mainstream in the market. In order to obtain better imaging quality, the lens that is traditionally equipped in mobile phone cameras adopts a three-piece or four-piece lens structure. And, with the development of technology and the increase of the diverse demands of users, and under this circumstances that the pixel area of photosensitive devices is shrinking steadily and the requirement of the system for the imaging quality is improving constantly, the five-piece, six-piece and seven-piece lens structure gradually appear in lens design. There is an urgent need for ultra-thin wide-angle camera lenses which have good optical characteristics and the chromatic aberration of which is fully corrected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the exemplary embodiments can be better understood with reference to the following drawings. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. 
         FIG. 1  is a schematic diagram of a camera optical lens in accordance with embodiment of the present invention; 
         FIG. 2  shows the longitudinal aberration of the camera optical lens shown in  FIG. 1 ; 
         FIG. 3  shows the lateral color of the camera optical lens shown in  FIG. 1 ; 
         FIG. 4  presents a schematic diagram of the field curvature and distortion of the camera optical lens shown in  FIG. 1 ; 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     The present disclosure will hereinafter be described in detail with reference to several exemplary embodiments. To make the technical problems to be solved, technical solutions and beneficial effects of the present disclosure more apparent, the present disclosure is described in further detail together with the figure and the embodiments. It should be understood the specific embodiments described hereby is only to explain the disclosure, not intended to limit the disclosure. 
     As referring to  FIG. 1 , the present invention provides a camera optical lens  10 .  FIG. 1  shows the camera optical lens  10  of embodiment of the present invention, the camera optical lens  10  comprises 4 lenses. Specifically, from the object side to the image side, the camera optical lens  10  comprises in sequence: a first lens L 1 , a second lens L 2 , a third lens L 3 , and a fourth lens L 4 . The first lens L 1  has a positive refractive power, the second lens L 2  has a negative refractive power, the third lens L 3  has a positive refractive power, the fourth lens L 4  has a negative refractive power. Optical element like optical filter GF can be arranged between the fourth lens L 4  and the image surface Si. The first lens L 1  is made of plastic material, the second lens L 2  is made of plastic material, the third lens L 3  is made of plastic material, and the fourth lens L 4  is made of plastic material. The first lens L 1  is a Fresnel lens, the second lens, the third lens, and the fourth lens are even aspheric surface lenses, wherein the first lens are configured to be Fresnel lenses which can reduce the cost. 
     The first lens L 1  has a positive refractive power with a convex image side surface relative to the proximal axis, the second lens L 2  has a negative refractive power with a convex object side surface relative to the proximal axis and a concave image side surface relative to the proximal axis, the third lens L 3  has a positive refractive power with a concave object side surface relative to the proximal axis and a convex image side surface relative to the proximal axis , the fourth lens L 4  has a negative refractive power with a convex object side surface relative to the proximal axis and a concave image side surface relative to the proximal axis. 
     Here, the focal length of the whole camera optical lens  10  is defined as f, the focal length of the first lens L 1  is defined as f1, the focal length of the third lens L 3  is defined as f3, the focal length of the fourth lens L 4  is defined as f4. Here the following condition should satisfied: 0.7&lt;f1/f&lt;1.25, −2.5&lt;f2/f&lt;−1.5, 0.60&lt;f3/f&lt;1.1, −1.5&lt;f4/f&lt;−0.7. 
     When the focal length of the camera optical lens  10  of the present invention, the focal length of each lens satisfy the above conditions, the refractive power configuration of each lens can be controlled/adjusted which can ensure the imaging quality and reducing the length of the system. Therefore, the imaging performance of the system has better imaging quality, more suitable for high-pixel of the portable camera. 
     In this embodiment, the focal length of the first lens L 1  is defined as f1, the focal length of the second lens L 2  is defined as f2, the focal length of the third lens L 3  is defined as f3, and the focal length of the fourth lens L 4  is defined as f4. Here the following condition should satisfied: 2≤f1≤5, −5≤f2≤−3, 1.5≤f3≤3, −5≤f4≤−2. The unit of distance, radius and center thickness is mm. With such design, the total optical length TTL of the whole camera optical lens  10  can be made as short as possible, thus the miniaturization characteristics can be maintained. 
     In this embodiment, the total optical length TTL of the camera optical lens and the image height IH satisfy the following condition: IH/TTL&gt;0.62. 
     In this embodiment, the total optical length TTL of the camera optical lens  10  is less than or equal to 3.6 mm the focal length of the camera optical lens  10  can be implemented the miniaturization characteristics. 
     In this embodiment, each lens of the camera optical lens adopts the Abbe number difference material, which can effectively correct color difference of the system and satisfy the color difference of the system ΔV&gt;30. 
     Further, in this embodiment, the refractive power of the first lens L 1  is defined as n1, the refractive power of the second lens L 2  is defined as n2, the refractive power of the third lens L 3  is defined as n3, and the refractive power of the fourth lens L 4  is defined as n4, the following condition shall be satisfied, 1.55≤n1≤1.65, 1.6≤n2≤1.67, 1.50≤n3≤1.55, 1.6≤n4≤1.67. Such design enables the lenses made from different optical materials to match each other better, and further enables the camera lens  10  to perform better imaging quality. 
     In addition, in this embodiment, set the first lens of the camera optical lens to the Fresnel surface, which can control more variables to reduce the effective “thickness” of each lens, thereby reducing the number of lenses, and therefore, the present invention can be effectively reduced the total length of the camera optical lens. 
     Preferably, inflexion points and/or arrest points can also be arranged on the object side surface and/or image side surface of the lens, so that the demand for high quality imaging can be satisfied, the description below can be referred for specific implementable scheme. 
     The design information of the camera optical lens  10  in this embodiment of the present invention is shown in the tables 1 and 2. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 focal length (mm) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f 
                 2.618 
               
               
                   
                 f1 
                 2.374 
               
               
                   
                 f2 
                 −4.599 
               
               
                   
                 f3 
                 2.187 
               
               
                   
                 f4 
                 −2.698 
               
               
                   
                 f12 
                 3.8925 
               
               
                   
                 f123 
                 2 
               
               
                   
                   
               
            
           
         
       
     
     Where: 
     the meaning of the various symbols is as follows. 
     f: the focal length of the camera optical lens; 
     f1: the focal length of the first lens; 
     f2: the focal length of the second lens; 
     f3: the focal length of the third lens; 
     f4: the focal length of the fourth lens; 
     f12: the combined focal length of the first lens and the second lens; 
     f123: the combined focal length of the first lens, the second lens, and the third lens; 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 Curvature 
                 Thickness/Distance 
                   
                 Abbe  
               
               
                   
                   
                 radius (R) 
                 (d) 
                 Refractive 
                 number 
               
               
                   
                   
                 (mm) 
                 (mm) 
                 power (nd) 
                 (νd) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 St 
                 St 
                 ∞ 
                 d0= 
                 −0.013 
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 L1 
                 R1 
                 3.133 
                 d1= 
                 0.680 
                 nd1 
                 1.54 
                 ν1 
                 56.12 
               
               
                   
                 R2 
                 −2.040 
                 d2= 
                 0.029 
                   
                   
                   
                   
               
               
                 L2 
                 R3 
                 3.407 
                 d3= 
                 0.311 
                 nd2 
                 1.64 
                 ν2 
                 22.41 
               
               
                   
                 R4 
                 1.532 
                 d4= 
                 0.491 
                   
                   
                   
                   
               
               
                 L3 
                 R5 
                 −1.923 
                 d5= 
                 0.597 
                 nd3 
                 1.54 
                 ν3 
                 56.12 
               
               
                   
                 R6 
                 −0.817 
                 d6= 
                 0.065 
                   
                   
                   
                   
               
               
                 L4 
                 R7 
                 1.360 
                 d7= 
                 0.402 
                 nd4 
                 1.54 
                 ν4 
                 56.12 
               
               
                   
                 R8 
                 0.633 
                 d8= 
                 0.500 
                   
                   
                   
                   
               
               
                 Glass 
                 R9 
                 ∞ 
                 d9= 
                 0.210 
                 ndg 
                 1.52 
                 νg 
                 64.17 
               
               
                   
                  R10 
                 ∞ 
                  d10= 
                 0.514 
               
               
                   
               
            
           
         
       
     
     In which, R 1  and R 2  represent respectively the object side surface and image side surface of the first lens L 1 , R 3  and R 4  represent respectively the object side surface and image side surface of the second lens L 2 , R 5  and R 6  represent respectively the object side surface and image side surface of the third lens L 3 , R 7  and R 8  represent respectively the object side surface and image side surface of the fourth lens L 4 , R 9  and R 10  represent respectively the object side surface and image side surface of the optical filter GF. Other, the meaning of the various symbols is as follows. 
     d0: The distance on-axis from aperture St to the object side surface of the first lens L 1 ; 
     d1: The thickness on-axis of the first lens L 1 ; 
     d2: The distance on-axis from the image side surface of the first lens L 1  to the object side surface of the second lens L 2 ; 
     d3: The thickness on-axis of the second lens L 2 ; 
     d4: The distance on-axis from the image side surface of the second lens L 2  to the object side surface of the third lens L 3 ; 
     d5: The thickness on-axis of the third lens L 3 ; 
     d6: The distance on-axis from the image side surface of the third lens L 3  to the object side surface of the fourth lens L 4 ; 
     d7: The thickness on-axis of the fourth lens L 4 ; 
     d8: The distance on-axis from the image side surface of the fourth lens L 4  to the object side surface of the optical filter GF; 
     d9: The thickness on-axis of the optical filter GF; 
     d10: The distance on-axis from the image side surface to the image surface of the optical filter GF; 
     nd1: The refractive power of the first lens L 1 ; 
     nd2: The refractive power of the second lens L 2 ; 
     nd3: The refractive power of the third lens L 3 ; 
     nd4: The refractive power of the fourth lens L 4 ; 
     ndg: The refractive power of the optical filter GF; 
     v1: The abbe number of the first lens L 1 ; 
     v2: The abbe number of the second lens L 2 ; 
     v3: The abbe number of the third lens L 3 ; 
     v4: The abbe number of the fourth lens L 4 ; 
     vg: The abbe number of the optical filter GF. 
     Table 3 shows the aspherical surface data of the camera optical lens  10  in this embodiment of the present invention. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                   
                 Conic Index 
                 Aspherical Surface Index 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                 k 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
                 A16 
               
               
                   
               
               
                 R1 
                 −1.3651E+02 
                   2.8301E−01 
                 −6.4209E−01 
                 −3.1114E+00 
                   1.1973E+01 
                   3.2112E+00 
                 −6.5753E+01 
                   7.4060E+01 
               
               
                 R2 
                 −4.2440E+00 
                 −4.1972E−01 
                   8.1231E−01 
                 −5.7263E−01 
                 −2.1440E+00 
                   5.0182E+00 
                 −3.5534E+00 
                   5.3833E−01 
               
               
                 R3 
                 −1.9089E+02 
                   3.4425E−02 
                 −5.4402E−01 
                   1.8413E+00 
                 −1.9315E+00 
                 −8.2833E−01 
                   3.2918E+00 
                 −1.7737E+00 
               
               
                 R4 
                   1.9372E−01 
                 −1.3747E−01 
                 −7.9812E−02 
                   4.3420E−01 
                 −5.1821E−01 
                 −3.1919E−01 
                   1.1740E+00 
                 −5.9153E−01 
               
               
                 R5 
                 −1.0383E+01 
                   2.8293E−02 
                 −3.0335E−02 
                 −2.2678E−01 
                   3.7445E−01 
                   2.9344E−02 
                 −6.3678E−01 
                   4.7308E−01 
               
               
                 R6 
                 −8.0712E−01 
                   3.5690E−01 
                 −4.6833E−01 
                   5.2630E−01 
                 −3.7032E−01 
                   9.4749E−02 
                   2.4177E−02 
                   6.4828E−03 
               
               
                 R7 
                 −1.0826E+01 
                 −1.6207E−01 
                 −4.2215E−02 
                   1.4934E−01 
                 −1.5957E−01 
                   9.4498E−02 
                 −2.8179E−02 
                   3.3086E−03 
               
               
                 R8 
                 −3.9435E+00 
                 −1.8915E−01 
                   1.2099E−01 
                 −6.3003E−02 
                   2.0335E−02 
                 −3.7380E−03 
                   3.3550E−04 
                 −9.5155E−06 
               
               
                   
               
            
           
         
       
     
     Table 4 and table 5 show the inflexion points and the arrest point design data of the camera optical lens  10  lens in this embodiment of the present invention. In which, R 1  and R 2  represent respectively the object side surface and image side surface of the first lens L 1 , R 3  and R 4  represent respectively the object side surface and image side surface of the second lens L 2 , R 5  and R 6  represent respectively the object side surface and image side surface of the third lens L 3 , R 7  and R 8  represent respectively the object side surface and image side surface of the fourth lens L 4 . The data in the column named “inflexion point position” are the vertical distances from the inflexion points arranged on each lens surface to the optic axis of the camera optical lens  10 . The data in the column named “arrest point position” are the vertical distances from the arrest points arranged on each lens surface to the optic axis of the camera optical lens  10 . 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                   
                   
                 Inflexion point 
               
               
                   
                 Inflexion point number 
                 Inflexion point position 1 
                 position 2 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 R1 
                 1 
                 0.405 
                   
               
               
                 R2 
                 0 
               
               
                 R3 
                 2 
                 0.385 
                 0.435 
               
               
                 R4 
                 0 
               
               
                 R5 
                 1 
                 0.855 
               
               
                 R6 
                 1 
                 0.925 
               
               
                 R7 
                 2 
                 0.395 
                 1.295 
               
               
                 R8 
                 1 
                 0.485 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Arrest point number 
                 Arrest point position 1 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 R1 
                 0 
                   
               
               
                 R2 
                 0 
               
               
                 R3 
                 0 
               
               
                 R4 
                 0 
               
               
                 R5 
                 0 
               
               
                 R6 
                 0 
               
               
                 R7 
                 1 
                 0.775 
               
               
                 R8 
                 1 
                 1.215 
               
               
                   
               
            
           
         
       
     
       FIG. 2  and  FIG. 3  show the longitudinal aberration and lateral color schematic diagrams after light with a wavelength of 470 nm, 555 nm and 650 nm passes the camera optical lens  10  in this embodiment.  FIG. 4  shows the field curvature and distortion schematic diagrams after light passes the camera optical lens  10  in this embodiment. 
     Table 6 shows the various values of the embodiment, and the values corresponding with the parameters which are already specified in the conditions. 
     As shown in Table 6, the embodiment satisfies the various conditions. 
     
       
         
           
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Embodiment 1 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 0.7 &lt; f1/f &lt; 1.25 
                 0.90679908 
               
               
                   
                 −2.5 &lt; f2/f &lt; −1.5 
                 −1.75668445 
               
               
                   
                 0.6 &lt; f3/f &lt; 1.1 
                 0.83537051 
               
               
                   
                 −1.5 &lt; f4/f &lt; −0.7 
                 −1.03055768 
               
               
                   
                 TTL ≤ 3.6 mm 
                 3.589 
               
               
                   
                 IH/TTL &gt; 0.62 
                 0.682641404 
               
               
                   
                   
               
            
           
         
       
     
     In this embodiment, the pupil entering diameter of the camera optical lens is 1.247 mm, the full vision field image height is 2.297 mm, the vision field angle in the diagonal direction is 84.00°. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of is parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms where the appended claims are expressed.