Abstract:
A six-piece optical lens system includes, in order from the object side to the image side: a first lens element with a negative refractive power having a concave image-side surface; a second lens element with a positive refractive power having a convex image-side surface; a third lens element with a positive refractive power having a convex object-side surface; a fourth lens element with a negative refractive power having a concave image-side surface; a fifth lens element with a positive refractive power having a convex object-side surface; a sixth lens element with a negative refractive power having a concave image-side surface, each of the first, second, fourth and sixth lens elements has at least one aspheric surface, one of the third and fifth lens elements being made of glass. Thereby, such a system can be applied to a high resolution mobile phone.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an optical lens system, and more particularly to a six-piece optical lens system. 
         [0003]    2. Description of the Prior Art 
         [0004]    A carrier provided with an optical lens system has become the trend of modern electronic products, and its functions of taking photographs or recording videos can not only increase the additional value of the products but also can get young people&#39;s attention. With the development of consumption habits, this trend is the gradual rise in other electronic carrier products, so many kinds of portable products are provided with a lens system, such as, digital camera, mobile phone, NB, game machine, Webcam and so on. However, such products have some limitations, that is, the inner space of the electronic carrier is largely compressed since it has become smaller in size, so the length of the lens system which is disposed on the carrier is limited. 
         [0005]    In addition, due to the fierce competition in industry and low profit, the electronic carrier with a higher resolution optical lens system has become the main marketing requirement, that is, the optical lens system should not only reduce the manufacturing and material costs but also provide a wide field of view and big stop. 
         [0006]    Current optical lens systems with a wide field of view mostly consist of five lens elements, including one gluing lens element, however, such a design can not meet the requirements of light, thin, short and small, and can not reduce the cost, weight, volume and thickness of the optical lens system. 
         [0007]    The present invention mitigates and/or obviates the aforementioned disadvantages. 
       SUMMARY OF THE INVENTION 
       [0008]    The primary objective of the present invention is to provide a six-piece optical lens system without having an excessively long total track length, the six-piece optical lens system not only can be applied to a high resolution mobile phone, but also has a wide field of view, big stop, high pixel, high resolution and low height. 
         [0009]    A six-piece optical lens system in accordance with the present invention comprises, in order from the object side to the image side: a first lens element with a negative refractive power having a concave image-side, at least one of an object-side and the image-side surfaces of the first lens element being aspheric; a second lens element with a positive refractive power having a convex image-side surface, at least one of an object-side and the image-side surfaces of the second lens element being aspheric; a third lens element with a positive refractive power having a convex object-side surface; a fourth lens element with a negative refractive power having a concave image-side surface, at least one of an object-side and the image-side surfaces of the fourth lens element being aspheric; a fifth lens element with a positive refractive power having a convex object-side surface; and a sixth lens element with a negative refractive power having a concave image-side, at least one of an object-side and the image-side surfaces of the sixth lens element being aspheric. One of the third lens element and the fifth lens element is made of glass. 
         [0010]    The present six-piece optical lens system further comprises a stop which is located between the first lens element and the second lens element. 
         [0011]    The present six-piece optical lens system further comprises a stop which is located between the second lens element and the third lens element. 
         [0012]    According to one aspect of the present six-piece optical lens system, the focal length of the first lens element is f1, the focal length of the third lens element is f3, and they satisfy the relation: 0.6&lt;|f1|/|f3|&lt;2.0. If |f1|/|f3| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, If |f1|/|f3| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0013]    According to one aspect of the present six-piece optical lens system, the focal length of the third lens element is f3, the focal length of the fourth lens element is f4, and they satisfy the relation: 0.5&lt;|f3|/|f4|&lt;1.8. If |f3|/|f4| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f3|/|f4| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0014]    According to one aspect of the present six-piece optical lens system, the focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they satisfy the relation: 0.4&lt;|f4|/|f5|&lt;1.2. If |f4|/|f5| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f4|/|f5| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0015]    According to another aspect of the present six-piece optical lens system, the focal length of the first lens element, the second lens element and the third lens element combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 0.5&lt;|f123|/|f1&lt;1.0. If |f123|/|f| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f123|/|f| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0016]    According to another aspect of the present six-piece optical lens system, the focal length of the fourth lens element, the fifth lens element and the sixth lens element combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 2.5&lt;|f456|/|f|&lt;4.8. If |f456|/|f| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f456|/|f| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0017]    According to another aspect of the present six-piece optical lens system, the focal length of the first lens element is f1, the focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: 1.4&lt;|f1|/|f23|&lt;2.1. If |f1|/|f23| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f1|/|f23| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0018]    According to another aspect of the present six-piece optical lens system, the focal length of the second lens element and the third lens element combined is f23, the focal length of the fourth lens element and the fifth lens element combined is f45, and they satisfy the relation: |f23|/|f45|&lt;0.3. If |f23|/|f45| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f23|/|f45| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0019]    According to another aspect of the present six-piece optical lens system, the focal length of the second lens element and the third lens element combined is f23, the focal length of the fifth lens element and the sixth lens element combined is f56, and they satisfy the relation: 0.3&lt;|f23|/|f56|&lt;0.8. If |f23|/|f56| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f23|/| 56 | exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low. 
         [0020]    According to another aspect of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TL, and they satisfy the relation: |f/TL|&lt;0.5. If |f/TL| satisfies the above relation, the total track length of the optical lens system can be relatively short, and the requirement of miniaturization can be satisfied. 
         [0021]    According to another aspect of the present six-piece optical lens system, the first lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the first lens element are aspheric. The second lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the second lens element are aspheric. The third lens element is made of plastic and has a convex image-side surface, and the object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element is made of plastic and has a concave object-side surface, and the object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element is made of glass and has a convex image-side surface, and the object-side surface and the image-side surface of the fifth lens element are aspheric. The sixth lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the sixth lens element are aspheric. 
         [0022]    According to another aspect of the present six-piece optical lens system, the first lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the first lens element are aspheric. The second lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the second lens element are aspheric. The third lens element is made of glass and has a convex image-side surface, and the object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element is made of plastic and has a concave object-side surface, and the object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element is made of plastic and has a convex image-side surface, and the object-side surface and the image-side surface of the fifth lens element are aspheric. The sixth lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the sixth lens element are aspheric. 
         [0023]    The present invention will be presented in further details from the following descriptions with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1A  shows an optical lens system in accordance with a first embodiment of the present invention; 
           [0025]      FIG. 1B  shows the longitudinal spherical aberration curve, the astigmatic field curve, and the distortion curve of the first embodiment of the present invention; 
           [0026]      FIG. 2A  shows an optical lens system in accordance with a second embodiment of the present invention; 
           [0027]      FIG. 2B  shows the longitudinal spherical aberration curve, the astigmatic field curve, and the distortion curve of the second embodiment of the present invention; 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Referring to  FIG. 1A , which shows a six-piece optical lens system in accordance with a first embodiment of the present invention, and  FIG. 1B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the first embodiment of the present invention. A six-piece optical lens system in accordance with the first embodiment of the present invention comprises, in order from the object side to the image side: 
         [0029]    A first lens element  110  with a negative refractive power made of plastic has a convex object-side surface  111  and a concave image-side surface  112 , and the object-side surface  111  and the image-side surface  112  of the first lens element  110  are aspheric. 
         [0030]    A second lens element  120  with a positive refractive power made of plastic has a convex object-side surface  121  and a convex image-side surface  122 , and the object-side surface  121  and the image-side surface  122  of the second lens element  120  are aspheric. 
         [0031]    A stop  100 . 
         [0032]    A third lens element  130  with a positive refractive power made of plastic has a convex object-side surface  131  and a convex image-side surface  132 , and the object-side surface  131  and the image-side surface  132  of the third lens element  130  are aspheric. 
         [0033]    A fourth lens element  140  with a negative refractive power made of plastic has a concave object-side surface  141  and a concave image-side surface  142 , and the object-side surface  141  and the image-side surface  142  of the fourth lens element  140  are aspheric. 
         [0034]    A fifth lens element  150  with a positive refractive power made of glass has a convex object-side surface  151  and a convex image-side surface  152 , and the object-side surface  151  and the image-side surface  152  of the fifth lens element  150  are aspheric. 
         [0035]    A sixth lens element  160  with a negative refractive power made of plastic has a convex object-side surface  161  and a concave image-side surface  162 , and the object-side surface  161  and the image-side surface  162  of the sixth lens element  160  are aspheric. 
         [0036]    An IR cut filter  170  made of glass is located between the image-side surface  162  of the sixth lens element  160  and an image plane  180  and has no influence on the focal length of the six-piece optical lens system. 
         [0037]    The equation for the aspheric surface profiles of the first embodiment is expressed as follows: 
         [0000]    
       
         
           
             z 
             = 
             
               
                 
                   ch 
                   2 
                 
                 
                   1 
                   + 
                   
                     
                       [ 
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               k 
                               + 
                               1 
                             
                             ) 
                           
                            
                           
                             c 
                             2 
                           
                            
                           
                             h 
                             2 
                           
                         
                       
                       ] 
                     
                     0.5 
                   
                 
               
               + 
               
                 Ah 
                 4 
               
               + 
               
                 Bh 
                 6 
               
               + 
               
                 Ch 
                 8 
               
               + 
               
                 Dh 
                 10 
               
               + 
               
                 Eh 
                 12 
               
               + 
               
                 Gh 
                 14 
               
               + 
               … 
             
           
         
       
     
         [0038]    wherein: 
         [0039]    z represents the value of a reference position with respect to a vertex of the surface of a lens and a position with a height h along the optical axis  190 ; 
         [0040]    k represents the conic constant; 
         [0041]    c represents the reciprocal of the radius of curvature; 
         [0042]    A, B, C, D, E, G, . . . : represent the high-order aspheric coefficients. 
         [0043]    In the first embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, and it satisfies the relation: 
         [0000]        f= 4.27. 
         [0044]    In the first embodiment of the present six-piece optical lens system, the f-number of the six-piece optical lens system is Fno, and it satisfies the relation: 
         [0000]        Fno= 2.6. 
         [0045]    In the first embodiment of the present six-piece optical lens system, the field of view of the six-piece optical lens system is 2ω, and it satisfies the relation: 
         [0000]      2ω=70°.
 
         [0046]    In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element  110  is f1, the focal length of the third lens element  130  is f3, and they satisfy the relation: 
         [0000]      | f 1 |/|f 3|=1.656. 
         [0047]    In the first embodiment of the present six-piece optical lens system, the focal length of the third lens element  130  is f3, the focal length of the fourth lens element  140  is f4, and they satisfy the relation: 
         [0000]      | f 3 |/|f 4|=0.774. 
         [0048]    In the first embodiment of the present six-piece optical lens system, the focal length of the fourth lens element  140  is f4, the focal length of the fifth lens element  150  is f5, and they satisfy the relation: 
         [0000]      | f 4 |/|f 5|=0.923. 
         [0049]    In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element  110 , the second lens element  120  and the third lens element  130  combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 
         [0000]      | f 123 |/|f|= 0.769. 
         [0050]    In the first embodiment of the present six-piece optical lens system, the focal length of the fourth lens element  140 , the fifth lens element  150  and the sixth lens element  160  combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 
         [0000]      | f 456 |/|f|= 2.974. 
         [0051]    In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element  110  is f1, the focal length of the second lens element  120  and the third lens element  130  combined is f23, and they satisfy the relation: 
         [0000]      | f 1 |/|f 23|=1.807. 
         [0052]    In the first embodiment of the present six-piece optical lens system, the focal length of the second lens element  120  and the third lens element  130  combined is f23, the focal length of the fourth lens element  140  and the fifth lens element  150  combined is f45, and they satisfy the relation: 
         [0000]      | f 23 |/|f 45|=0.138. 
         [0053]    In the first embodiment of the present six-piece optical lens system, the focal length of the second lens element  120  and the third lens element  130  combined is f23, the focal length of the fifth lens element  150  and the sixth lens element  160  combined is f56, and they satisfy the relation: 
         [0000]      | f 23 |/|f 56|=0.489. 
         [0054]    In the first embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface  111  of the first lens element  110  to the image plane  180  along the optical axis  190  is TL, and they satisfy the relation: 
         [0000]      | f/TL|= 0.266. 
         [0055]    The detailed optical data of the first embodiment is shown in table 1, and the aspheric surface data is shown in table 2, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. In the tables 1 and 2, the surfaces  1  and  2  represent the object-side surface  111  and the image-side surface  112  of the first lens element  110 , respectively, the surfaces  3  and  4  represent the object-side surface  121  and the image-side surface  122  of the second lens element  120 , respectively, the surfaces  6  and  7  represent the object-side surface  131  and the image-side surface  132  of the third lens element  130 , respectively, the surfaces  8  and  9  represent the object-side surface  141  and the image-side surface  142  of the fourth lens element  140 , respectively, and the surfaces  12  and  13  represent the object-side surface  161  and the image-side surface  162  of the sixth lens element  160 , respectively. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 (Embodiment 1) 
               
               
                 f(focal length) = 4.27 mm, Fno = 2.6, 2ω = 70°. 
               
             
          
           
               
                 Surface 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 nd 
                 vd 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Infinity 
                 Infinity 
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 2.390466(ASP) 
                 0.424625 
                 Plastic 
                 1.535 
                 56 
               
               
                 2 
                   
                 0.94691(ASP) 
                 1.173357 
               
               
                 3 
                 Lens 2 
                 27.13449(ASP) 
                 0.760859 
                 Plastic 
                 1.634 
                 23.9 
               
               
                 4 
                   
                 −10.2075(ASP) 
                 0.077425 
               
               
                 5 
                 Stop 
                 Infinity 
                 0.203418 
               
               
                 6 
                 Lens 3 
                 3.146663(ASP) 
                 1.014048 
                 Plastic 
                 1.535 
                 56 
               
               
                 7 
                   
                 −1.40964(ASP) 
                 0.066544 
               
               
                 8 
                 Lens 4 
                 −14.2314(ASP) 
                 0.465062 
                 Plastic 
                 1.634 
                 23.9 
               
               
                 9 
                   
                 1.861593(ASP) 
                 0.175693 
               
               
                 10 
                 Lens 5 
                 4.452003 
                 1.470815 
                 Glass 
                 1.7292 
                 54.6735 
               
               
                 11 
                   
                 −3.16638 
                 0.484929 
               
               
                 12 
                 Lens 6 
                 6.571901(ASP) 
                 0.641133 
                 Plastic 
                 1.634 
                 23.9 
               
               
                 13 
                   
                 2.079743(ASP) 
                 0.286166 
               
               
                 14 
                 IR-filter 
                 Infinity 
                 0.3 
                 Glass 
                 1.5168 
                 64.16734 
               
               
                 15 
                   
                 Infinity 
                 0.4565 
               
               
                 16 
                 Image 
                 Infinity 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface 
               
             
          
           
               
                   
                 1 
                 2 
                 3 
                 4 
                 6 
               
               
                   
               
               
                 K = 
                 −1.21007 
                 −0.69271 
                 −103.802 
                 78.08349 
                 −13.0111 
               
               
                 A = 
                 0.002574 
                 0.06573 
                 −0.02283 
                 0.003542 
                 0.143772 
               
               
                 B = 
                 −0.00141 
                 −0.00836 
                 −0.01706 
                 −0.09798 
                 −0.41986 
               
               
                 C = 
                 −7.4E−05 
                 0.021619 
                 0.021042 
                 0.210496 
                 0.55819 
               
               
                 D = 
                 5.84E−06 
                 −0.00085 
                 −0.00407 
                 −0.11702 
                 −0.28189 
               
               
                   
               
             
          
           
               
                   
                 Surface 
               
             
          
           
               
                   
                 7 
                 8 
                 9 
                 12 
                 13 
               
               
                   
               
               
                 K = 
                 −1.88673 
                 139.7694 
                 −7.91724 
                 −148.079 
                 −10.0119 
               
               
                 A = 
                 0.029929 
                 −0.04391 
                 0.020106 
                 −0.08092 
                 −0.03892 
               
               
                 B = 
                 −0.11385 
                 −0.02956 
                 −0.01036 
                 −0.00202 
                 0.002968 
               
               
                 C = 
                 0.070151 
                 0.032348 
                 0.004507 
                 0.001816 
                 −0.00038 
               
               
                 D = 
                 −0.00588 
                 −0.00586 
                 −0.00094 
                 −0.00049 
                 1.98E−05 
               
               
                   
               
             
          
         
       
     
         [0056]    Referring to  FIG. 2A , which shows a six-piece optical lens system in accordance with a second embodiment of the present invention, and  FIG. 2B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the second embodiment of the present invention. A six-piece optical lens system in accordance with the second embodiment of the present invention comprises, in order from the object side to the image side: 
         [0057]    A first lens element  210  with a negative refractive power made of plastic has a convex object-side surface  211  and a concave image-side surface  212 , and the object-side surface  211  and the image-side surface  212  of the first lens element  210  are aspheric. 
         [0058]    A stop  200 . 
         [0059]    A second lens element  220  with a positive refractive power made of plastic has a convex object-side surface  221  and a convex image-side surface  222 , and the object-side surface  221  and the image-side surface  222  of the second lens element  220  are aspheric. 
         [0060]    A third lens element  230  with a positive refractive power made of glass has a convex object-side surface  231  and a convex image-side surface  232 , and the object-side surface  231  and the image-side surface  232  of the third lens element  230  are aspheric. 
         [0061]    A fourth lens element  240  with a negative refractive power made of plastic has a concave object-side surface  241  and a concave image-side surface  242 , and the object-side surface  241  and the image-side surface  242  of the fourth lens element  240  are aspheric. 
         [0062]    A fifth lens element  250  with a positive refractive power made of plastic has a convex object-side surface  251  and a convex image-side surface  252 , and the object-side surface  251  and the image-side surface  252  of the fifth lens element  250  are aspheric. 
         [0063]    A sixth lens element  260  with a negative refractive power made of plastic has a convex object-side surface  261  and a concave image-side surface  262 , and the object-side surface  261  and the image-side surface  262  of the sixth lens element  260  are aspheric. 
         [0064]    An IR cut filter  270  made of glass is located between the image-side surface  262  of the fifth lens element  260  and an image plane  280  and has no influence on the focal length of the six-piece optical lens system. 
         [0065]    The equation for the aspheric surface profiles of the second embodiment is expressed as follows: 
         [0000]    
       
         
           
             z 
             = 
             
               
                 
                   ch 
                   2 
                 
                 
                   1 
                   + 
                   
                     
                       [ 
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               k 
                               + 
                               1 
                             
                             ) 
                           
                            
                           
                             c 
                             2 
                           
                            
                           
                             h 
                             2 
                           
                         
                       
                       ] 
                     
                     0.5 
                   
                 
               
               + 
               
                 Ah 
                 4 
               
               + 
               
                 Bh 
                 6 
               
               + 
               
                 Ch 
                 8 
               
               + 
               
                 Dh 
                 10 
               
               + 
               
                 Eh 
                 12 
               
               + 
               
                 Gh 
                 14 
               
               + 
               … 
             
           
         
       
     
         [0066]    wherein: 
         [0067]    z represents the value of a reference position with respect to a vertex of the surface of a lens and a position with a height h along the optical axis  290 ; 
         [0068]    k represents the conic constant; 
         [0069]    c represents the reciprocal of the radius of curvature; 
         [0070]    A, B, C, D, E, G, . . . : represent the high-order aspheric coefficients. 
         [0071]    In the second embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, and it satisfies the relation: 
         [0000]        f= 3.9. 
         [0072]    In the second embodiment of the present six-piece optical lens system, the f-number of the six-piece optical lens system is Fno, and it satisfies the relation: 
         [0000]        Fno= 2.4. 
         [0073]    In the second embodiment of the present six-piece optical lens system, the field of view of the six-piece optical lens system is 2ω, and it satisfies the relation: 
         [0000]      2ω=74°.
 
         [0074]    In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element  210  is f1, the focal length of the third lens element  230  is f3, and they satisfy the relation: 
         [0000]      | f 1 |/|f 3|=0.977. 
         [0075]    In the second embodiment of the present six-piece optical lens system, the focal length of the third lens element  230  is f3, the focal length of the fourth lens element  240  is f4, and they satisfy the relation: 
         [0000]      | f 3 |/|f 4|=1.545. 
         [0076]    In the second embodiment of the present six-piece optical lens system, the focal length of the fourth lens element  240  is f4, the focal length of the fifth lens element  250  is f5, and they satisfy the relation: 
         [0000]      | f 4 |/|f 5|=0.668. 
         [0077]    In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element  210 , the second lens element  220  and the third lens element  230  combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 
         [0000]      | f 123 |/|f|= 0.719. 
         [0078]    In the second embodiment of the present six-piece optical lens system, the focal length of the fourth lens element  240 , the fifth lens element  250  and the sixth lens element  260  combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 
         [0000]      | f 456 |/|f|= 4.353. 
         [0079]    In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element  210  is f1, the focal length of the second lens element  220  and the third lens element  230  combined is f23, and they satisfy the relation: 
         [0000]      | f 1 |/|f 23|=1.703. 
         [0080]    In the second embodiment of the present six-piece optical lens system, the focal length of the second lens element  220  and the third lens element  230  combined is f23, the focal length of the fourth lens element  240  and the fifth lens element  250  combined is f45, and they satisfy the relation: 
         [0000]      | f 23 |/|f 45|=0.079. 
         [0081]    In the second embodiment of the present six-piece optical lens system, the focal length of the second lens element  220  and the third lens element  230  combined is f23, the focal length of the fifth lens element  250  and the sixth lens element  260  combined is f56, and they satisfy the relation: 
         [0000]      | f 23 |/|f 56|=0.604. 
         [0082]    In the second embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface  211  of the first lens element  210  to the image plane  280  along the optical axis  290  is TL, and they satisfy the relation: 
         [0000]      | f/TL|= 0.266. 
         [0083]    The detailed optical data of the second embodiment is shown in table 3, and the aspheric surface data is shown in table 4, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. In the tables 3 and 4, the surfaces  1  and  2  represent the object-side surface  211  and the image-side surface  212  of the first lens element  210 , respectively, the surfaces  4  and  5  represent the object-side surface  221  and the image-side surface  222  of the second lens element  220 , respectively, the surfaces  8  and  9  represent the object-side surface  241  and the image-side surface  242  of the fourth lens element  240 , respectively, the surfaces  10  and  11  represent the object-side surface  251  and the image-side surface  252  of the fifth lens element  250 , respectively, and the surfaces  12  and  13  represent the object-side surface  261  and the image-side surface  262  of the sixth lens element  260 , respectively. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 (Embodiment 2) 
               
               
                 f(focal length) = 3.9 mm, Fno = 2.4, 2ω = 74°. 
               
             
          
           
               
                 Sur- 
                   
                 Curvature 
                   
                   
                   
                   
               
               
                 face 
                   
                 Radius 
                 Thickness 
                 Material 
                 nd 
                 vd 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Infinity 
                 Infinity 
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 4.33095(ASP) 
                 0.399254 
                 Plastic 
                 1.535 
                 56 
               
               
                 2 
                   
                 1.147043(ASP) 
                 1.436016 
               
               
                 3 
                 Stop 
                 Infinity 
                 0.047929 
               
               
                 4 
                 Lens 2 
                 24.43088(ASP) 
                 0.72482 
                 Plastic 
                 1.535 
                 56 
               
               
                 5 
                   
                 −1.73003(ASP) 
                 0.205304 
               
               
                 6 
                 Lens 3 
                 6.533319 
                 1.312139 
                 Glass 
                 1.6204 
                 60.3439 
               
               
                 7 
                   
                 −2.54141 
                 0.144328 
               
               
                 8 
                 Lens 4 
                 −2.25137(ASP) 
                 0.502847 
                 Plastic 
                 1.634 
                 23.9 
               
               
                 9 
                   
                 3.291223(ASP) 
                 0.059682 
               
               
                 10 
                 Lens 5 
                 3.581905(ASP) 
                 1.224091 
                 Plastic 
                 1.535 
                 56 
               
               
                 11 
                   
                 −2.59942(ASP) 
                 0.140857 
               
               
                 12 
                 Lens 6 
                 1.350809(ASP) 
                 0.398828 
                 Plastic 
                 1.535 
                 56 
               
               
                 13 
                   
                 1.094418(ASP) 
                 1.021131 
               
               
                 14 
                 IR-filter 
                 Infinity 
                 0.3 
                 Glass 
                 1.5168 
                 64.1674 
               
               
                 15 
                   
                 Infinity 
                 0.037 
               
               
                 16 
                 Image 
                 Infinity 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
                 8 
               
               
                   
               
               
                 K = 
                 3.484695 
                 −0.02167 
                 900.0333 
                 1.329657 
                 0.098966 
               
               
                 A = 
                 0.040739 
                 0.106388 
                 0.096257 
                 0.04289 
                 −0.00291 
               
               
                 B = 
                 −0.02152 
                 −0.0346 
                 −0.51833 
                 −0.079 
                 0.003155 
               
               
                 C = 
                 0.003529 
                 0.020722 
                 0.652999 
                 0.070671 
                 0.000598 
               
               
                 D = 
                 −0.0004 
                 −0.008 
                 −0.45356 
                 −0.0355 
                 0.000187 
               
               
                   
               
             
          
           
               
                   
                 Surface 
               
             
          
           
               
                   
                 9 
                 10 
                 11 
                 12 
                 13 
               
               
                   
               
               
                 K = 
                 −11.7226 
                 −0.12739 
                 −1.47663 
                 −0.87401 
                 −0.86495 
               
               
                 A = 
                 0.013874 
                 −0.00084 
                 0.014088 
                 −0.1092 
                 −0.15306 
               
               
                 B = 
                 −0.00099 
                 −0.00136 
                 0.004058 
                 −0.0025 
                 0.021411 
               
               
                 C = 
                 0.000285 
                 7.03E−04 
                 1.51E−04 
                 0.002312 
                 −0.00236 
               
               
                 D = 
                 5.15E−05 
                 −1.12E−04 
                 −6.74E−05 
                 −1.17E−04 
                 8.67E−05 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Embodiment 1 
                 Embodiment 2 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 f 
                 4.27 
                 3.9 
               
               
                   
                 Fno 
                 2.6 
                 2.4 
               
               
                   
                 2ω 
                 70 
                 74 
               
               
                   
                 |f1|/|f3| 
                 1.656 
                 0.977 
               
               
                   
                 |f3|/|f4| 
                 0.774 
                 1.545 
               
               
                   
                 |f4|/|f5| 
                 0.923 
                 0.668 
               
               
                   
                 |f123|/|f| 
                 0.769 
                 0.719 
               
               
                   
                 |f456|/|f| 
                 2.974 
                 4.353 
               
               
                   
                 |f1|/|f23| 
                 1.807 
                 1.703 
               
               
                   
                 |f23|/|f45| 
                 0.138 
                 0.079 
               
               
                   
                 |f23|/|f56| 
                 0.489 
                 0.604 
               
               
                   
                 |f/TL| 
                 0.266 
                 0.266 
               
               
                   
                   
               
             
          
         
       
     
         [0084]    It is to be noted that the tables 1-4 show different data from the different embodiments, however, the data of the different embodiments is obtained from experiments. Therefore, any product of the same structure is deemed to be within the scope of the present invention even if it uses different data. Table 5 lists the relevant data for the various embodiments of the present invention. 
         [0085]    In the present six-piece optical lens system, if the object-side or the image-side surface of the lens elements is convex, the object-side or the image-side surface of the lens elements in proximity of the optical axis is convex. If the object-side or the image-side surface of the lens elements is concave, the object-side or the image-side surface of the lens elements in proximity of the optical axis is concave. 
         [0086]    While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.