Abstract:
A miniaturized optical lens system comprises, in order from the object side to the image side: a first lens element with positive refractive power having a convex object-side surface, a concave image-side surface and one of the surfaces being aspheric; and a second lens element with negative refractive power having a concave object-side surface, a convex image-side surface and one of the surfaces being aspheric. The optical lens system is further provided with an aperture stop. Such arrangements can effectively reduce the volume of the optical lens system, correct aberrations and astigmatism of the system in order to obtain higher image quality.

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 miniaturized optical lens system used in electronics. 
         [0003]    2. Description of the Prior Art 
         [0004]    In recent years, since the optical lens system has become smaller in size, and due to advances in semiconductor manufacturing, the electronic sensor of a conventional digital camera is typically a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) sensor, the pixel size of sensors has been reduced gradually, and miniaturization has become the trend of modern electronic products. Therefore, the miniaturized optical lens system with good image quality is still the trend of the mainstream market. 
         [0005]    In order to correct aberrations, conventional miniaturized lens systems mostly consist of three lens elements, and one of the typical structures is the positive-negative-positive Triplet type. However, when the size of the lens assembly is reduced substantially, less space is available for constructing the optical system, making it difficult to incorporate three lens elements into the optical system. Furthermore, the lens elements must become thinner, causing poor homogeneity of the plastic material within the lens elements manufactured by injection molding process. 
         [0006]    Hence, only the optical lens system with two lens elements is feasible in order to effectively reduce the total track length of the optical lens system. Additionally, in order to correct aberrations, the aperture stop is normally located in the front of the optical system. However, the second lens element of this optical lens system is biconcave, which performs poorly than a meniscus lens element in terms of aberration and astigmatism corrections. 
         [0007]    Therefore, the present invention is aimed at providing an easy-to-manufacture miniaturized optical lens system which can effectively reduce the total track length of the optical lens system and provide great image quality. 
         [0008]    The present invention mitigates and/or obviates the afore-mentioned disadvantages. 
       SUMMARY OF THE INVENTION 
       [0009]    The primary objective of the present invention is to provide a miniaturized optical lens system comprising two lens elements to effectively reduce the volume of the optical lens system, correct aberrations and astigmatism of the system and provide higher resolution. 
         [0010]    A miniaturized 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 positive refractive power having a convex object-side surface and a concave image-side surface, at least one of the object-side and the image-side surfaces of the first lens element being aspheric; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, at least one of the object-side and the image-side surfaces of the second lens element being aspheric. In the miniaturized optical lens system, there are two lens elements with refractive power. The Abbe number of the first lens element is V 1 , the Abbe number of the second lens element is V 2 , the focal length of the miniaturized optical lens system is f, the focal length of the second lens element is f 2 , and the radius of curvature of the object-side surface of the second lens element is R 3 . The optical lens system is further provided with an aperture stop, the distance from the aperture stop to the image plane along an optical axis is SL, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TTL, and they satisfy the relations: 15&lt;|V 1 −V 2 |&lt;48; −0.43&lt;f/f 2 &lt;0; −1.50&lt;R 3 /f&lt;−0.40; 0.9&lt;SL/TTL&lt;1.1. Such arrangements can effectively reduce the volume of the system, correct aberrations as well as astigmatism of the system, and obtain high resolution. 
         [0011]    The first lens element with positive refractive power can provide partial refractive power for the miniaturized optical lens system, and reduce the total track length of the optical lens system. 
         [0012]    The second lens element with negative refractive power can effectively correct aberrations of the miniaturized optical lens system, and improve the image quality. 
         [0013]    The first lens element has a convex object-side surface and a concave image-side surface, which will be favorable to correct astigmatism of the system. 
         [0014]    The second lens element has a concave object-side surface and a convex image-side surface, which will be favorable to correct the high order aberrations of the system. 
         [0015]    If 15&lt;|V 1 −V 2 |&lt;48 is satisfied, it will be favorable to correct the chromatic aberration within the system. Preferably, V 1  and V 2  satisfy the relation: 
         [0000]      23 &lt;|V 1 −V 2|&lt;45, 
         [0016]    Furthermore, V 1  and V 2  can satisfy the relation: 
         [0000]      30 &lt;|V 1 −V 2|&lt;42. 
         [0017]    If −0.43&lt;f/f 2 &lt;0 is satisfied, the refractive power of the second lens element can effectively correct aberrations of the system. Preferably, f/f 2  satisfies the relation: 
         [0000]      −0.27 &lt;f/f 2&lt;0.
 
         [0018]    If −1.50&lt;R 3 /f&lt;−0.40 is satisfied, the second lens element can effectively correct the astigmatism. Preferably, R 3 /f satisfies the relation: 
         [0000]      −1.20 &lt;R 3 /f&lt;− 0.50.
 
         [0019]    If 0.9&lt;SL/TTL&lt;1.1 is satisfied, the miniaturized optical lens system can utilize the telecentric feature to reduce the total track length of the optical system. 
         [0020]    According to one aspect of the present miniaturized optical lens system, the radius of curvature of the object-side surface of the first lens element is R 1 , and the radius of curvature of the image-side surface of the first lens element is R 2 . If R 1 /R 2  satisfies the relation: 0&lt;R 1 /R 2 &lt;0.8, it can effectively correct the spherical aberration within the system. Preferably, R 1 /R 2  satisfies the relation: 
         [0000]      0.40 &lt;R 1 /R 2&lt;0.60. 
         [0021]    According to another aspect of the present miniaturized optical lens system, the center thickness of the first lens element is CT 1 , and the center thickness of the second lens element is CT 2 . If CT 1 /CT 2  satisfies the relation: 0.25&lt;CT 1 /CT 2 &lt;0.95, the thickness of the first lens element and the second lens element can reduce the difficulties in manufacturing and assembling processes. Preferably, CT 1 /CT 2  satisfies the relation: 
         [0000]      0.40 &lt;CT 1 /CT 2&lt;0.76. 
         [0022]    According to another aspect of the present miniaturized optical lens system, the refractive index of the first lens element is N 1 , and the refractive index of the second lens element is N 2 . If N 1  and N 2  satisfy the relation: N 2 &gt;N 1 , the refractive index of the first lens element and the second lens element can reduce the total track length of the system and maintain superior image quality. Preferably, N 1  and N 2  satisfy the relation: 
         [0000]      0.04 &lt;N 2 −N 1&lt;0.18. 
         [0023]    According to another aspect of the present miniaturized optical lens system, the distance from the image-side surface of the second lens element to the image plane along the optical axis is Bf, and the center thickness of the second lens element is CT 2 . If Bf/CT 2  satisfies the relation: 0.4&lt;Bf/CT 2 &lt;2.0, there will be enough space between the second lens element and the electronic sensor for other components. Preferably, Bf/CT 2  satisfies the relation: 
         [0000]      0.95 &lt;Bf/CT 2&lt;1.65. 
         [0024]    According to another aspect of the present miniaturized optical lens system, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TTL, an electronic sensor is provided on the image plane, and half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH. If TTL/ImgH satisfies the relation: TTL/ImgH&lt;1.95, the optical lens system will be favorable to stay compact, which allows the lens system to be used in the portable electronics. 
         [0025]    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 
         [0026]      FIG. 1A  shows an optical lens system in accordance with a first embodiment of the present invention; 
           [0027]      FIG. 1B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the first embodiment of the present invention; 
           [0028]      FIG. 2A  shows an optical lens system in accordance with a second embodiment of the present invention; 
           [0029]      FIG. 2B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the second embodiment of the present invention; 
           [0030]      FIG. 3A  shows an optical lens system in accordance with a third embodiment of the present invention; 
           [0031]      FIG. 3B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the third embodiment of the present invention; 
           [0032]      FIG. 4A  shows an optical lens system in accordance with a fourth embodiment of the present invention; 
           [0033]      FIG. 4B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fourth embodiment of the present invention; 
           [0034]      FIG. 5A  shows an optical lens system in accordance with a fifth embodiment of the present invention; 
           [0035]      FIG. 5B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fifth embodiment of the present invention; 
           [0036]      FIG. 6A  shows an optical lens system in accordance with a sixth embodiment of the present invention; and 
           [0037]      FIG. 6B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the sixth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Referring to  FIG. 1A , which shows a miniaturized 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 miniaturized optical lens system in accordance with the first embodiment of the present invention comprises, in order from the object side to the image side: 
         [0039]    A plastic first lens element  110  with positive refractive power 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. 
         [0040]    A plastic second lens element  120  with negative refractive power has a concave 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. 
         [0041]    An aperture stop  100  is located between an object to be photographed (not shown) and the first lens element  110 . 
         [0042]    An IR cut filter  170  which is made of glass is located between the image-side surface  122  of the second lens element  120  and an image plane  190  and has no influence on the focal length of the optical lens system. 
         [0043]    The equation for the aspheric surface profiles of the first embodiment is expressed as follows: 
         [0000]    
       
         
           
             
               X 
                
               
                 ( 
                 Y 
                 ) 
               
             
             = 
             
               
                 
                   ( 
                   
                     
                       Y 
                       2 
                     
                     / 
                     R 
                   
                   ) 
                 
                 / 
                 
                   ( 
                   
                     1 
                     + 
                     
                       sqrt 
                        
                       
                         ( 
                         
                           1 
                           - 
                           
                             
                               ( 
                               
                                 1 
                                 - 
                                 k 
                               
                               ) 
                             
                             * 
                             
                               
                                 ( 
                                 
                                   Y 
                                   / 
                                   R 
                                 
                                 ) 
                               
                               2 
                             
                           
                         
                         ) 
                       
                     
                   
                   ) 
                 
               
               + 
               
                 
                   ∑ 
                   i 
                 
                  
                 
                   
                     ( 
                     Ai 
                     ) 
                   
                   * 
                   
                     ( 
                     
                       Y 
                       i 
                     
                     ) 
                   
                 
               
             
           
         
       
     
         [0044]    wherein: 
         [0045]    X: the height of a point on the aspheric lens surface at a distance Y from the optical axis relative to the tangential plane at the aspheric surface vertex; 
         [0046]    Y: the distance from the point on the curve of the aspheric surface to the optical axis, 
         [0047]    k: the conic coefficient; 
         [0048]    Ai: the aspheric surface coefficient of order i. 
         [0049]    In the first embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=1.84. 
         [0050]    In the first embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=2.45. 
         [0051]    In the first embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=33.0. 
         [0052]    In the first embodiment of the present optical lens system, the Abbe number of the first lens element  110  is V 1 , the Abbe number of the second lens element  120  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=32.5. 
         [0053]    In the first embodiment of the present optical lens system, the refractive index of the first lens element  110  is N 1 , the refractive index of the second lens element  120  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.09. 
         [0054]    In the first embodiment of the present optical lens system, the center thickness of the first lens element  110  is CT 1 , the center thickness of the second lens element  120  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.59. 
         [0055]    In the first embodiment of the present optical lens system, the radius of curvature of the object-side surface  111  of the first lens element  110  is R 1 , the radius of curvature of the image-side surface  112  of the first lens element  110  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.57. 
         [0056]    In the first embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  121  of the second lens element  120  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 1.01. 
         [0057]    In the first embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  120  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.004.
 
         [0058]    In the first embodiment of the present optical lens system, the distance from the image-side surface  122  of the second lens element  120  to the image plane  190  along the optical axis  150  is Bf, the center thickness of the second lens element  120  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=1.21. 
         [0059]    In the first embodiment of the present optical lens system, the distance from the aperture stop  100  to the image plane  190  along the optical axis  150  is SL, the distance from the object-side surface  111  of the first lens element  110  to the image plane  190  along the optical axis  150  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.94. 
         [0060]    In the first embodiment of the present optical lens system, the distance from the object-side surface  111  of the first lens element  110  to the image plane  190  along the optical axis  150  is TTL, an electronic sensor (not shown) is provided on the image plane  190 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 1.71. 
         [0061]    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. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 (Embodiment 1) 
               
               
                 f(focal length) = 1.84 mm, Fno = 2.45, HFOV (half of field of view) = 33.0 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Aperture 
                 Plano 
                 −0.130  
               
               
                   
                 Stop 
               
               
                 2 
                 Lens 1 
                  0.515050(ASP) 
                 0.386 
                 Plastic 
                 1.544 
                 55.9 
                 1.62 
               
               
                 3 
                   
                  0.910960(ASP) 
                 0.130 
               
               
                 4 
                   
                 Plano 
                 0.108 
               
               
                 5 
                 Lens 2 
                 −1.851840(ASP) 
                 0.649 
                 Plastic 
                 1.632 
                 23.4 
                 −508.36 
               
               
                 6 
                   
                 −2.115360(ASP) 
                 0.400 
               
               
                 7 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
               
               
                 8 
                   
                 Plano 
                 0.249 
               
               
                 9 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm, and the effective radius of the surface # 4 is 0.31 mm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 2 
                 3 
                 5 
                 6 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 1.53602E−01 
                 6.50219E+00 
                 2.31273E+01 
                 5.08130E+00 
               
               
                 A4 = 
                 −1.60334E−01 
                 3.33540E−01 
                 9.02796E−03 
                 −3.24474E−01 
               
               
                 A6 = 
                 2.02042E+00 
                 −9.50396E+00 
                 −2.57243E+01 
                 4.44899E+00 
               
               
                 A8 = 
                 1.43785E+01 
                 1.02997E+02 
                 2.60214E+02 
                 −4.12745E+01 
               
               
                 A10 = 
                 −4.17690E+02 
                 1.80469E+01 
                 −8.19364E+02 
                 1.84209E+02 
               
               
                 A12 = 
                 2.93865E+03 
                 −9.89554E+03 
                 −8.87704E+03 
                 −4.51311E+02 
               
               
                 A14 = 
                 −7.06669E+03 
                 5.02631E+04 
                 5.18671E+04 
                 5.73247E+02 
               
               
                 A16 = 
                 4.84967E+03 
                 −2.84781E+03 
                 −4.60415E+04 
                 −2.98581E+02 
               
               
                   
               
             
          
         
       
     
         [0062]    Referring to  FIG. 2A , which shows a miniaturized 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. The second embodiment of the present invention comprises, in order from the object side to the image side: 
         [0063]    A plastic first lens element  210  with positive refractive power 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. 
         [0064]    A plastic second lens element  220  with negative refractive power has a concave 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. 
         [0065]    An aperture stop  200  is located between an object to be photographed (not shown) and the first lens element  210 . 
         [0066]    An IR cut filter  270  which is made of glass is located between the image-side surface  222  of the second lens element  220  and an image plane  290  and has no influence on the focal length of the miniaturized optical lens system. 
         [0067]    The equation for the aspheric surface profiles of the second embodiment has the same form as that of the first embodiment. 
         [0068]    In the second embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=1.96. 
         [0069]    In the second embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=2.85. 
         [0070]    In the second embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=31.0. 
         [0071]    In the second embodiment of the present optical lens system, the Abbe number of the first lens element  210  is V 1 , the Abbe number of the second lens element  220  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=32.1. 
         [0072]    In the second embodiment of the present optical lens system, the refractive index of the first lens element  210  is N 1 , the refractive index of the second lens element  220  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.09. 
         [0073]    In the second embodiment of the present optical lens system, the center thickness of the first lens element  210  is CT 1 , the center thickness of the second lens element  220  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.51. 
         [0074]    In the second embodiment of the present optical lens system, the radius of curvature of the object-side surface  211  of the first lens element  210  is R 1 , the radius of curvature of the image-side surface  212  of the first lens element  210  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.48. 
         [0075]    In the second embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  221  of the second lens element  220  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 0.61. 
         [0076]    In the second embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  220  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.272.
 
         [0077]    In the second embodiment of the present optical lens system, the distance from the image-side surface  222  of the second lens element  220  to the image plane  290  along the optical axis  250  is Bf, the center thickness of the second lens element  220  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=1.11. 
         [0078]    In the second embodiment of the present optical lens system, the distance from the aperture stop  200  to the image plane  290  along the optical axis  250  is SL, the distance from the object-side surface  211  of the first lens element  210  to the image plane  290  along the optical axis  250  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.94. 
         [0079]    In the second embodiment of the present optical lens system, the distance from the object-side surface  211  of the first lens element  210  to the image plane  290  along the optical axis  250  is TTL, an electronic sensor (not shown) is provided on the image plane  290 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 1.75. 
         [0080]    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. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 (Embodiment 2) 
               
               
                 f(focal length) = 1.96 mm, Fno = 2.85, HFOV (half of field of view) = 31.0 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Aperture 
                 Plano 
                 −0.127  
               
               
                   
                 Stop 
               
               
                 2 
                 Lens 1 
                  0.511290(ASP) 
                 0.344 
                 Plastic 
                 1.544 
                 55.9 
                 1.48 
               
               
                 3 
                   
                  1.066010(ASP) 
                 0.332 
               
               
                 4 
                 Lens 2 
                 −1.189920(ASP) 
                 0.673 
                 Plastic 
                 1.634 
                 23.8 
                 −7.20 
               
               
                 5 
                   
                 −1.962620(ASP) 
                 0.300 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
               
               
                 7 
                   
                 Plano 
                 0.246 
               
               
                 8 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 −1.02842E−02 
                 8.54454E+00 
                 1.00000E+01 
                 6.67736E−02 
               
               
                 A4 = 
                 −4.95418E−02 
                 4.80407E−01 
                 2.00069E−01 
                 −4.87595E−01 
               
               
                 A6 = 
                 4.14473E+00 
                 −1.38709E+01 
                 −3.08483E+01 
                 5.12086E+00 
               
               
                 A8 = 
                 −9.25889E+00 
                 1.62786E+02 
                 3.24484E+02 
                 −4.54919E+01 
               
               
                 A10 = 
                 −2.16113E+02 
                 −1.96302E+02 
                 −9.13241E+02 
                 1.94474E+02 
               
               
                 A12 = 
                 2.63336E+03 
                 −9.37811E+03 
                 −1.00177E+04 
                 −4.49499E+02 
               
               
                 A14 = 
                 −7.05992E+03 
                 4.97092E+04 
                 5.16904E+04 
                 5.33268E+02 
               
               
                 A16 = 
                 1.72901E+03 
                 −4.01151E+03 
                 −4.69971E+04 
                 −2.57215E+02 
               
               
                   
               
             
          
         
       
     
         [0081]    Referring to  FIG. 3A , which shows a miniaturized optical lens system in accordance with a third embodiment of the present invention, and  FIG. 3B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the third embodiment of the present invention. The third embodiment of the present invention comprises, in order from the object side to the image side: 
         [0082]    A plastic first lens element  310  with positive refractive power has a convex object-side surface  311  and a concave image-side surface  312 , and the object-side surface  311  and the image-side surface  312  of the first lens element  310  are aspheric. 
         [0083]    A plastic second lens element  320  with negative refractive power has a concave object-side surface  321  and a convex image-side surface  322 , and the object-side surface  321  and the image-side surface  322  of the second lens element  320  are aspheric. 
         [0084]    An aperture stop  300  is located between an object to be photographed (not shown) and the first lens element  310 . 
         [0085]    An IR cut filter  370  which is made of glass is located between the image-side surface  322  of the second lens element  320  and an image plane  390  and has no influence on the focal length of the miniaturized optical lens system. 
         [0086]    The equation for the aspheric surface profiles of the third embodiment has the same form as that of the first embodiment. 
         [0087]    In the third embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=1.89. 
         [0088]    In the third embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=3.00. 
         [0089]    In the third embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=31.9. 
         [0090]    In the third embodiment of the present optical lens system, the Abbe number of the first lens element  310  is V 1 , the Abbe number of the second lens element  320  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=25.6. 
         [0091]    In the third embodiment of the present optical lens system, the refractive index of the first lens element  310  is N 1 , the refractive index of the second lens element  320  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.05. 
         [0092]    In the third embodiment of the present optical lens system, the center thickness of the first lens element  310  is CT 1 , the center thickness of the second lens element  320  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.47. 
         [0093]    In the third embodiment of the present optical lens system, the radius of curvature of the object-side surface  311  of the first lens element  310  is R 1 , the radius of curvature of the image-side surface  312  of the first lens element  310  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.48. 
         [0094]    In the third embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  321  of the second lens element  320  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 0.60. 
         [0095]    In the third embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  320  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.110.
 
         [0096]    In the third embodiment of the present optical lens system, the distance from the image-side surface  322  of the second lens element  320  to the image plane  390  along the optical axis  350  is Bf, the center thickness of the second lens element  320  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=1.05. 
         [0097]    In the third embodiment of the present optical lens system, the distance from the aperture stop  300  to the image plane  390  along the optical axis  350  is SL, the distance from the object-side surface  311  of the first lens element  310  to the image plane  390  along the optical axis  350  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.95. 
         [0098]    In the third embodiment of the present optical lens system, the distance from the object-side surface  311  of the first lens element  310  to the image plane  390  along the optical axis  350  is TTL, an electronic sensor (not shown) is provided on the image plane  390 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 1.75. 
         [0099]    The detailed optical data of the third embodiment is shown in table 5, and the aspheric surface data is shown in table 6, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 (Embodiment 3) 
               
               
                 f(focal length) = 1.89 mm, Fno = 3.00, HFOV (half of field of view) = 31.9 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Apertutre 
                 Plano 
                 −0.104  
               
               
                   
                 Stop 
               
               
                 2 
                 Lens 1 
                  0.497000(ASP) 
                 0.335 
                 Plastic 
                 1.530 
                 55.8 
                 1.48 
               
               
                 3 
                   
                  1.041050(ASP) 
                 0.292 
               
               
                 4 
                 Lens 2 
                 −1.142930(ASP) 
                 0.717 
                 Plastic 
                 1.583 
                 30.2 
                 −17.18 
               
               
                 5 
                   
                 −1.588260(ASP) 
                 0.300 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
               
               
                 7 
                   
                 Plano 
                 0.255 
               
               
                 8 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 2.13205E−02 
                 9.01904E+00 
                 9.55693E+00 
                 8.68756E−01 
               
               
                 A4 = 
                 −1.35579E−01 
                 6.43032E−01 
                 2.57182E−01 
                 −3.80804E−01 
               
               
                 A6 = 
                 5.83765E+00 
                 −1.93627E+01 
                 −3.57890E+01 
                 4.57065E+00 
               
               
                 A8 = 
                 −1.21610E+01 
                 2.44550E+02 
                 4.00370E+02 
                 −4.39616E+01 
               
               
                 A10 = 
                 −2.46772E+02 
                 −6.44429E+02 
                 −1.37003E+03 
                 1.94162E+02 
               
               
                 A12 = 
                 2.68401E+03 
                 −9.37903E+03 
                 −1.00493E+04 
                 −4.52091E+02 
               
               
                 A14 = 
                 −5.72799E+03 
                 4.97092E+04 
                 5.16904E+04 
                 5.32680E+02 
               
               
                 A16 = 
                 4.52619E+03 
                 −4.01151E+03 
                 −4.69971E+04 
                 −2.53281E+02 
               
               
                   
               
             
          
         
       
     
         [0100]    Referring to  FIG. 4A , which shows a miniaturized optical lens system in accordance with a fourth embodiment of the present invention, and  FIG. 4B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fourth embodiment of the present invention. The fourth embodiment of the present invention comprises, in order from the object side to the image side: 
         [0101]    A plastic first lens element  410  with positive refractive power has a convex object-side surface  411  and a concave image-side surface  412 , and the object-side surface  411  and the image-side surface  412  of the first lens element  410  are aspheric. 
         [0102]    A plastic second lens element  420  with negative refractive power has a concave object-side surface  421  and a convex image-side surface  422 , and the object-side surface  421  and the image-side surface  422  of the second lens element  420  are aspheric. 
         [0103]    An aperture stop  400  is located between an object to be photographed (not shown) and the first lens element  410 . 
         [0104]    An IR cut filter  470  which is made of glass is located between the image-side surface  422  of the second lens element  420  and an image plane  490  and has no influence on the focal length of the miniaturized optical lens system. 
         [0105]    The equation for the aspheric surface profiles of the fourth embodiment has the same form as that of the first embodiment. 
         [0106]    In the fourth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=1.89. 
         [0107]    In the fourth embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=2.60. 
         [0108]    In the fourth embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=31.9. 
         [0109]    In the fourth embodiment of the present optical lens system, the Abbe number of the first lens element  410  is V 1 , the Abbe number of the second lens element  420  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=34.4. 
         [0110]    In the fourth embodiment of the present optical lens system, the refractive index of the first lens element  410  is N 1 , the refractive index of the second lens element  420  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.12. 
         [0111]    In the fourth embodiment of the present optical lens system, the center thickness of the first lens element  410  is CT 1 , the center thickness of the second lens element  420  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.53. 
         [0112]    In the fourth embodiment of the present optical lens system, the radius of curvature of the object-side surface  411  of the first lens element  410  is R 1 , the radius of curvature of the image-side surface  412  of the first lens element  410  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.45. 
         [0113]    In the fourth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  421  of the second lens element  420  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 0.59. 
         [0114]    In the fourth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  420  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.167.
 
         [0115]    In the fourth embodiment of the present optical lens system, the distance from the image-side surface  422  of the second lens element  420  to the image plane  490  along the optical axis  450  is Bf, the center thickness of the second lens element  420  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=1.23. 
         [0116]    In the fourth embodiment of the present optical lens system, the distance from the aperture stop  400  to the image plane  490  along the optical axis  450  is SL, the distance from the object-side surface  411  of the first lens element  410  to the image plane  490  along the optical axis  450  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.94. 
         [0117]    In the fourth embodiment of the present optical lens system, the distance from the object-side surface  411  of the first lens element  410  to the image plane  490  along the optical axis  450  is TTL, an electronic sensor (not shown) is provided on the image plane  490 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 1.75. 
         [0118]    The detailed optical data of the fourth embodiment is shown in table 7, and the aspheric surface data is shown in table 8, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 7 
               
             
             
               
                   
               
               
                 (Embodiment 4) 
               
               
                 f(focal length) = 1.89 mm, Fno = 2.60, HFOV (half of field of view) = 31.9 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Aperture 
                 Plano 
                 −0.130  
               
               
                   
                 Stop 
               
               
                 2 
                 Lens 1 
                  0.508240(ASP) 
                 0.353 
                 Plastic 
                 1.530 
                 55.8 
                 1.45 
               
               
                 3 
                   
                  1.133700(ASP) 
                 0.119 
               
               
                 4 
                   
                 Plano 
                 0.147 
               
               
                 5 
                 Lens 2 
                 −1.112980(ASP) 
                 0.664 
                 Plastic 
                 1.650 
                 21.4 
                 −11.33 
               
               
                 6 
                   
                 −1.619320(ASP) 
                 0.300 
               
               
                 7 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
               
               
                 8 
                   
                 Plano 
                 0.316 
               
               
                 9 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm, and the effective radius of the surface # 4 is 0.32 mm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 2 
                 3 
                 5 
                 6 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 −3.24319E−02 
                 9.13652E+00 
                 1.00000E+01 
                 8.14838E−01 
               
               
                 A4 = 
                 −5.84482E−02 
                 4.06160E−01 
                 7.30045E−01 
                 −4.43182E−01 
               
               
                 A6 = 
                 4.22515E+00 
                 −1.62641E+01 
                 −4.30019E+01 
                 5.03218E+00 
               
               
                 A8 = 
                 −4.12576E+00 
                 1.87714E+02 
                 4.77943E+02 
                 −4.36090E+01 
               
               
                 A10 = 
                 −2.63255E+02 
                 −5.27506E+02 
                 −1.76674E+03 
                 1.88199E+02 
               
               
                 A12 = 
                 2.39826E+03 
                 −9.22449E+03 
                 −9.99965E+03 
                 −4.49782E+02 
               
               
                 A14 = 
                 −5.50091E+03 
                 5.02631E+04 
                 5.18671E+04 
                 5.59136E+02 
               
               
                 A16 = 
                 4.84968E+03 
                 −2.84780E+03 
                 −4.60415E+04 
                 −2.85783E+02 
               
               
                   
               
             
          
         
       
     
         [0119]    Referring to  FIG. 5A , which shows a miniaturized optical lens system in accordance with a fifth embodiment of the present invention, and  FIG. 5B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fifth embodiment of the present invention. The fifth embodiment of the present invention comprises, in order from the object side to the image side: 
         [0120]    A plastic first lens element  510  with positive refractive power has a convex object-side surface  511  and a concave image-side surface  512 , and the object-side surface  511  and the image-side surface  512  of the first lens element  510  are aspheric. 
         [0121]    A plastic second lens element  520  with negative refractive power has a concave object-side surface  521  and a convex image-side surface  522 , and the object-side surface  521  and the image-side surface  522  of the second lens element  520  are aspheric. 
         [0122]    An aperture stop  500  is located between the first lens element  510  and the second lens element  520 . 
         [0123]    An IR cut filter  570  which is made of glass is located between the image-side surface  522  of the second lens element  520  and an image plane  590  and has no influence on the focal length of the miniaturized optical lens system. 
         [0124]    The equation for the aspheric surface profiles of the fifth embodiment has the same form as that of the first embodiment. 
         [0125]    In the fifth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=2.98. 
         [0126]    In the fifth embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=2.85. 
         [0127]    In the fifth embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=26.1. 
         [0128]    In the fifth embodiment of the present optical lens system, the Abbe number of the first lens element  510  is V 1 , the Abbe number of the second lens element  520  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=33.1. 
         [0129]    In the fifth embodiment of the present optical lens system, the refractive index of the first lens element  510  is N 1 , the refractive index of the second lens element  520  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.09. 
         [0130]    In the fifth embodiment of the present optical lens system, the center thickness of the first lens element  510  is CT 1 , the center thickness of the second lens element  520  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.76. 
         [0131]    In the fifth embodiment of the present optical lens system, the radius of curvature of the object-side surface  511  of the first lens element  510  is R 1 , the radius of curvature of the image-side surface  512  of the first lens element  510  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.44. 
         [0132]    In the fifth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  521  of the second lens element  520  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 0.65. 
         [0133]    In the fifth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  520  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.390.
 
         [0134]    In the fifth embodiment of the present optical lens system, the distance from the image-side surface  522  of the second lens element  520  to the image plane  590  along the optical axis  550  is Bf, the center thickness of the second lens element  520  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=0.97. 
         [0135]    In the fifth embodiment of the present optical lens system, the distance from the aperture stop  500  to the image plane  590  along the optical axis  550  is SL, the distance from the object-side surface  511  of the first lens element  510  to the image plane  590  along the optical axis  550  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.75. 
         [0136]    In the fifth embodiment of the present optical lens system, the distance from the object-side surface  511  of the first lens element  510  to the image plane  590  along the optical axis  550  is TTL, an electronic sensor (not shown) is provided on the image plane  590 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 2.13. 
         [0137]    The detailed optical data of the fifth embodiment is shown in table 9, and the aspheric surface data is shown in table 10, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 9 
               
             
             
               
                   
               
               
                 (Embodiment 5) 
               
               
                 f(focal length) = 2.98 mm, Fno = 2.85, HFOV (half of field of view) = 26.1 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                  0.85548(ASP) 
                 0.684 
                 Plastic 
                 1.543 
                 56.5 
                 2.30 
               
               
                 2 
                   
                  1.95494(ASP) 
                 0.093 
               
               
                 3 
                 Aperture 
                 Plano 
                 0.520 
               
               
                   
                 Stop 
               
               
                 4 
                 Lens 2 
                 −1.93634(ASP) 
                 0.900 
                 Plastic 
                 1.632 
                 23.4 
                 −7.64 
               
               
                 5 
                   
                 −3.81480(ASP) 
                 0.330 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
               
               
                 7 
                   
                 Plano 
                 0.347 
               
               
                 8 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 10 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 −1.22685E+00 
                 −3.55759E+01 
                 −9.60858E+00 
                 −1.58493E+01 
               
               
                 A4 = 
                 1.95825E−01 
                 6.47511E−01 
                 −6.45558E−01 
                 −2.45010E−01 
               
               
                 A6 = 
                 3.04279E−01 
                 −1.47200E+00 
                 −2.13476E−01 
                 2.65305E−01 
               
               
                 A8 = 
                 −1.90985E−02 
                 6.43013E+00 
                 −1.62519E+01 
                 −5.02538E−01 
               
               
                 A10 = 
                 −8.31666E−01 
                 −1.35214E+01 
                 1.00677E+02 
                 1.56351E−01 
               
               
                 A12 = 
                 2.16030E+00 
                 2.57298E+01 
                 −2.27533E+02 
                 2.37133E−01 
               
               
                 A14 = 
                   
                   
                   
                 −1.73812E−01 
               
               
                   
               
             
          
         
       
     
         [0138]    Referring to  FIG. 6A , which shows a miniaturized optical lens system in accordance with a sixth embodiment of the present invention, and  FIG. 6B  shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the sixth embodiment of the present invention. The sixth embodiment of the present invention comprises, in order from the object side to the image side: 
         [0139]    A plastic first lens element  610  with positive refractive power has a convex object-side surface  611  and a concave image-side surface  612 , and the object-side surface  611  and the image-side surface  612  of the first lens element  610  are aspheric. 
         [0140]    A plastic second lens element  620  with negative refractive power has a concave object-side surface  621  and a convex image-side surface  622 , and the object-side surface  621  and the image-side surface  622  of the second lens element  620  are aspheric. 
         [0141]    An aperture stop  600  is located between the first lens element  610  and the second lens element  620 . 
         [0142]    An IR cut filter  670  which is made of glass is located between the image-side surface  622  of the second lens element  620  and an image plane  690  and has no influence on the focal length of the miniaturized optical lens system. 
         [0143]    The equation for the aspheric surface profiles of the sixth embodiment has the same form as that of the first embodiment. 
         [0144]    In the sixth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, and it satisfies the relation: 
         [0000]      f=2.97. 
         [0145]    In the sixth embodiment of the present optical lens system, the f-number of the miniaturized optical lens system is Fno, and it satisfies the relation: 
         [0000]      Fno=3.00. 
         [0146]    In the sixth embodiment of the present optical lens system, half of the maximal field of view is HFOV, and it satisfies the relation: 
         [0000]      HFOV=26.0. 
         [0147]    In the sixth embodiment of the present optical lens system, the Abbe number of the first lens element  610  is V 1 , the Abbe number of the second lens element  620  is V 2 , and they satisfy the relation: 
         [0000]      | V 1 −V 2|=35.1. 
         [0148]    In the sixth embodiment of the present optical lens system, the refractive index of the first lens element  610  is N 1 , the refractive index of the second lens element  620  is N 2 , and they satisfy the relation: 
         [0000]        N 2 −N 1=0.11. 
         [0149]    In the sixth embodiment of the present optical lens system, the center thickness of the first lens element  610  is CT 1 , the center thickness of the second lens element  620  is CT 2 , and they satisfy the relation: 
         [0000]        CT 1 /CT 2=0.75. 
         [0150]    In the sixth embodiment of the present optical lens system, the radius of curvature of the object-side surface  611  of the first lens element  610  is R 1 , the radius of curvature of the image-side surface  612  of the first lens element  610  is R 2 , and they satisfy the relation: 
         [0000]        R 1 /R 2=0.53. 
         [0151]    In the sixth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the radius of curvature of the object-side surface  621  of the second lens element  620  is R 3 , and they satisfy the relation: 
         [0000]        R 3 /f=− 0.69. 
         [0152]    In the sixth embodiment of the present optical lens system, the focal length of the miniaturized optical lens system is f, the focal length of the second lens element  620  is f 2 , and they satisfy the relation: 
         [0000]        f/f 2=−0.225.
 
         [0153]    In the sixth embodiment of the present optical lens system, the distance from the image-side surface  622  of the second lens element  620  to the image plane  690  along the optical axis  650  is Bf, the center thickness of the second lens element  620  is CT 2 , and they satisfy the relation: 
         [0000]        Bf/CT 2=0.96. 
         [0154]    In the sixth embodiment of the present optical lens system, the distance from the aperture stop  600  to the image plane  690  along the optical axis  650  is SL, the distance from the object-side surface  611  of the first lens element  610  to the image plane  690  along the optical axis  650  is TTL, and they satisfy the relation: 
         [0000]        SL/TTL= 0.74. 
         [0155]    In the sixth embodiment of the present optical lens system, the distance from the object-side surface  611  of the first lens element  610  to the image plane  690  along the optical axis  650  is TTL, an electronic sensor (not shown) is provided on the image plane  690 , half of the diagonal length of the electronic sensor&#39;s effective pixel region is ImgH, and they satisfy the relation: 
         [0000]        TTL/ImgH= 2.16. 
         [0156]    The detailed optical data of the sixth embodiment is shown in table 11, and the aspheric surface data is shown in table 12, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 11 
               
             
             
               
                   
               
               
                 (Embodiment 6) 
               
               
                 f(focal length) = 2.97 mm, Fno = 3.00, HFOV (half of field of view) = 26.0 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                  0.82172(ASP) 
                 0.697 
                 Plastic 
                 1.543 
                 56.5 
                 2.41 
               
               
                 2 
                   
                  1.54768(ASP) 
                 0.099 
               
               
                 3 
                 Aperture 
                 Plano 
                 0.483 
               
               
                   
                 Stop 
               
               
                 4 
                 Lens 2 
                 −2.05023(ASP) 
                 0.930 
                 Plastic 
                 1.650 
                 21.4 
                 −13.20 
               
               
                 5 
                   
                 −3.17590(ASP) 
                 0.300 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
               
               
                 7 
                   
                 Plano 
                 0.395 
               
               
                 8 
                 Image 
                 Plano 
               
               
                   
               
               
                 Note: 
               
               
                 reference wavelength is: d-line 587.6 nm. 
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 12 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 −9.74860E−01 
                 −5.50877E+01 
                 −5.44079E+01 
                 −9.18573E+00 
               
               
                 A4 = 
                 2.01757E−01 
                 1.67251E+00 
                 −1.10883E+00 
                 −1.47982E−01 
               
               
                 A6 = 
                 6.77107E−02 
                 −7.58210E+00 
                 3.17915E+00 
                 9.29297E−02 
               
               
                 A8 = 
                 1.86153E+00 
                 3.26998E+01 
                 −2.31643E+01 
                 −3.29757E−01 
               
               
                 A10 = 
                 −5.67283E+00 
                 −4.06950E+01 
                 8.33246E+01 
                 1.80031E−01 
               
               
                 A12 = 
                 7.50152E+00 
                 −1.42867E+01 
                 −1.34726E+02 
                 8.19105E−02 
               
               
                 A14 = 
                   
                   
                   
                 −8.78244E−02 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 Embodiment 1 
                 Embodiment 2 
                 Embodiment 3 
                 Embodiment 4 
                 Embodiment 5 
                 Embodiment 6 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 f 
                 1.84 
                 1.96 
                 1.89 
                 1.89 
                 2.98 
                 2.97 
               
               
                 Fno 
                 2.45 
                 2.85 
                 3.00 
                 2.60 
                 2.85 
                 3.00 
               
               
                 HFOV 
                 33.0 
                 31.0 
                 31.9 
                 31.9 
                 26.1 
                 26.0 
               
               
                 |V1 − V2| 
                 32.5 
                 32.1 
                 25.6 
                 34.4 
                 33.1 
                 35.1 
               
               
                 N2 − N1 
                 0.09 
                 0.09 
                 0.05 
                 0.12 
                 0.09 
                 0.11 
               
               
                 CT1/CT2 
                 0.59 
                 0.51 
                 0.47 
                 0.53 
                 0.76 
                 0.75 
               
               
                 R1/R2 
                 0.57 
                 0.48 
                 0.48 
                 0.45 
                 0.44 
                 0.53 
               
               
                 R3/f 
                 −1.01 
                 −0.61 
                 −0.60 
                 −0.59 
                 −0.65 
                 −0.69 
               
               
                 f/f2 
                 −0.004 
                 −0.272 
                 −0.110 
                 −0.167 
                 −0.390 
                 −0.225 
               
               
                 Bf/CT2 
                 1.21 
                 1.11 
                 1.05 
                 1.23 
                 0.97 
                 0.96 
               
               
                 SL/TTL 
                 0.94 
                 0.94 
                 0.95 
                 0.94 
                 0.75 
                 0.74 
               
               
                 TTL/ImgH 
                 1.71 
                 1.75 
                 1.75 
                 1.75 
                 2.13 
                 2.16 
               
               
                   
               
             
          
         
       
     
         [0157]    It is to be noted that the tables 1-12 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 13 lists the relevant data for the various embodiments of the present invention. 
         [0158]    In the present miniaturized optical lens system, the lens elements can be made of glass or plastic. If the lens elements are made of glass, there is more freedom in distributing the refractive power of the optical lens system. If the lens elements are made of plastic, the cost will be effectively reduced. Plastic lens elements can have aspheric surfaces, which allow more design parameter freedom (than spherical surfaces), so as to reduce the aberration and the number of the lens elements, as well as the total track length of the optical lens system. 
         [0159]    In the present miniaturized 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. 
         [0160]    The present miniaturized optical lens system can have at least one stop to reduce flares, in order to further improve the image quality. 
         [0161]    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.