Abstract:
An optical lens for image pickup, sequentially arranged from an object side to an image side, comprising: the first lens element with positive refractive power having a convex object-side surface, the second lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the plastic third lens element with positive refractive power having a concave object-side surface and a convex image-side surface with both being aspheric, the plastic fourth lens element with positive refractive power having a convex object-side surface and a concave image-side surface with both being aspheric. By such arrangements, the optical lens for image pickup satisfies conditions related to reduce the sensitivity and to shorten the total length for use in compact cameras and mobile phones with camera functionalities.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical lens for image pickup, and more particularly to the optical lens for image pickup with a short total length and a low cost, and comprised of four lens elements and applied to electronic products. 
     2. Description of the Related Art 
     In compact electronic products such as digital still cameras and mobile phone cameras, an optical lens for image pickup is installed for capturing images of an object, and the optical lens for image pickup tends to be developed with a compact design and a low cost, while meeting the user requirements for high resolution and high image quality. 
     In general, a conventional optical lens for image pickup of a compact electronic product comes with different designs, including the two-lens, three-lens, four-lens, and five-or-more lens designs. If the image quality of a compact electronic product is taken into consideration, the optical lens for image pickup with a design of four lens elements or five lens elements has advantages on image aberration and modulation transfer function (MTF) performance, wherein the design with four lens element having less lenses than the design with five lens elements and a lower manufacturing cost is suitable for electronic products having the high quality and high pixel requirements. 
     In various optical lenses for image pickup with the four-lens design, the prior art adopts different combinations of positive and negative refractive powers, wherein the first lens element has positive refractive power, the second lens element has negative refractive power, the third lens element has positive refractive power, and the fourth lens element has negative refractive power as disclosed in WIPO Pat. No. WO2010026691 and U.S. publication and U.S. Pat. No. 7,785,023, 2008/180813, and U.S. Pat. No. 7,755,853 to provide a better aberration correction. 
     In products such as compact digital cameras, web cameras, and mobile phone cameras, the optical lens for image pickup requires a compact design, a short focal length, and a good aberration correction. In a design with the combination of the first lens element with positive refractive power, the second lens element with negative refractive power, the third lens element with positive refractive power, and the fourth lens element with positive refractive power, a compact requirement can be achieved most probably as disclosed in U.S. Pat. Nos. 7,443,611, 7,375,903 and 7,345,830. However, the optical lens for image pickup disclosed in these patents comprises the third lens element having a convex object side in proximity to the optical axis and turning into a concave shape at the edge of the lens, so that the curvature has a drastic change and a complicated shape, and it is relatively difficult to manufacture the lenses of this sort, which is unfavorable for production. In addition, the installation of the meniscus third lens element can correct the astigmatic field curving, and the meniscus third lens element has a shorter effective diameter and a greater curvature of the image-side surface to provide better positive refractive power and suppress the light effectively, so that there is a better flexibility for the installation space of the lenses. The difficulty of the cooling and deformation controls during the production of thicker second lens element and the longer total length of the lens can be overcome. Therefore, the present invention provides a practical design for shortening the optical lens for image pickup, while using four lenses with different refractive powers, and a combination of convex and concave optical surfaces, not only reducing the total length of the optical lens for image pickup, but also improving the image quality, reducing the manufacturing cost by using simple lenses, and applying the lenses for electronic products. 
     SUMMARY OF THE INVENTION 
     Therefore, it is a primary objective of the present invention to provide an optical lens for image pickup, sequentially arranged from an object side to an image side, comprising: the first lens element, the second lens element, the third lens element, and the fourth lens element, wherein the first lens element with positive refractive power has a convex object-side surface; the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface; the plastic third lens element with positive refractive power has a concave object-side surface and a convex image-side surface, and both object-side surface and image-side surface thereof being aspheric; and the plastic fourth lens element with positive refractive power has a convex object-side surface and a concave image-side surface, and both object-side surface and image-side surface being aspheric. The optical lens for image pickup satisfies the following relations:
 
0.20&lt;( R   3   −R   4 )/( R   3   +R   4 )&lt;0.70;  (1)
 
|( R   5   −R   6 )/( R   5   +R   6 )|&lt;0.21;  (2)
 
0.1 &lt;R   4   /f&lt; 0.5.  (3)
 
     Wherein, R 3  is a curvature radius of the object-side surface of the second lens element, R 4  is a curvature radius of the image-side surface of the second lens element, R 5  is a curvature radius of the object-side surface of the third lens element, R 6  is a curvature radius of the image-side surface of the third lens element, and f is a focal length of the optical lens for image pickup. 
     On the other hand, the present invention provides an optical lens for image pickup as described above, wherein at least one of the object-side surface and the image-side surface of the fourth lens element has at least one inflection point, and the following relations are satisfied in addition to the relations (1), (2) and (3):
 
|( R   7   −R   8 )/( R   7   +R   8 )|&lt;0.18;  (4)
 
28 &lt;v   1   −v   2 &lt;42;  (5)
 
0.3&lt;( R   3   −R   4 )/( R   3   +R   4 )&lt;0.52;  (6)
 
0 &lt;f/f   3 &lt;0.40;  (7)
 
0 &lt;|f   2   |/f   3 &lt;0.5;  (8)
 
0 &lt;T   12   /T   23 &lt;0.4;  (9)
 
0.2 &lt;R   1   /f&lt; 0.5.  (10)
 
     Wherein, R 1  is a curvature radius of the object-side surface of the first lens element, R 3  is the curvature radius of the object-side surface of the second lens element, R 4  is the curvature radius of the image-side surface of the second lens element, R 7  is a curvature radius of the object-side surface of the fourth lens element, R 8  is a curvature radius of the image-side surface of the fourth lens element, f is the focal length of the optical lens for image pickup, f 2  is a focal length of the second lens element, f 3  is a focal length of the third lens element, T 12  is an axial distance between the first lens element and the second lens element, T 23  is an axial distance between the second lens element and the third lens element, v 1  is an Abbe number of the first lens element, and v 2  is an Abbe number of the second lens element. 
     On the other hand, the present invention provides an optical lens for image pickup, as described above, further comprises an image sensor at an image plane, wherein the first lens element has a concave image-side surface, and at least one of the object-side surface and image-side surface of the fourth lens element has at least one inflection point, and one or more of the following relation are satisfied, in addition to the relations (1), (2), (3) and (4):
 
0.5 &lt;T   23   /T   34 &lt;1.5;  (11)
 
0.2&lt;( CT   2   /f )*10&lt;0.8;  (12)
 
 TTL/ImgH&lt; 2.1.  (13)
 
     Wherein, T 23  is the axial distance between the second lens element and the third lens element, T 34  is an axial distance between the third lens element and the fourth lens element, f is the focal length of the optical lens for image pickup, CT 2  is a central thickness of the second lens element, TTL is an axial distance between the object-side surface of the first lens element and the image plane, and ImgH is half of the diagonal length of an effective photosensitive area of the image sensor. 
     Another objective of the present invention provides an optical lens for image pickup, sequentially arranged from an object side to an image side, comprising: the first lens element, the second lens element, the third lens element, and the fourth lens element; wherein the first lens element with positive refractive power has a convex object-side surface; the second lens element with negative refractive power has a convex object-side surface and concave image-side surface; the third lens element with positive refractive power is made of plastic and has a concave object-side surface and a convex image-side surface, and both object-side surface and image-side surface being aspheric; the fourth lens element with positive refractive power is made of plastic and has a convex object-side surface and a concave image-side surface, and both object-side surface and image-side surface being aspheric; and the optical lens for image pickup satisfies the following relations:
 
0.20&lt;( R   3   −R   4 )/( R   3   +R   4 )&lt;0.70;  (1)
 
|( R   2   −R   8 )/( R   2   +R   8 )|&lt;0.18;  (4)
 
0.1 &lt;R   4   /f&lt; 0.5;  (3)
 
0 &lt;f/f   3 &lt;0.40.  (7)
 
     Wherein, R 3  is a curvature radius of the object-side surface of the second lens element, R 4  is a curvature radius of the image-side surface of the second lens element, R 7  is a curvature radius of the object-side surface of the fourth lens element, R 8  is a curvature radius of the image-side surface of the fourth lens element, f is a focal length of the optical lens for image pickup, and f 3  is a focal length of the third lens element. 
     On the other hand, the present invention provides an optical lens for image pickup as described above, wherein at least one of the object-side surface and the image-side surface of the fourth lens element has at least one inflection point, and the optical lens for image pickup satisfies one or more of the following relations in addition to the relations (1), (4), (3) and (7):
 
0 &lt;|f   2   |/f   3 &lt;0.5;  (8)
 
28 &lt;v   1   −v   2 &lt;40;  (14)
 
0.5 &lt;T   23   /T   34 &lt;1.5;  (11)
 
|( R   5   −R   6 )/( R   5   +R   6 )|&lt;0.21;  (2)
 
0.3&lt;( R   3   −R   4 )/( R   3   +R   4 )&lt;0.52;  (6)
 
0.2&lt;( CT   2   /f )*10&lt;0.8.  (12)
 
     Wherein f is the focal length of the optical lens for image pickup, f 2  is a focal length of the second lens element, f 3  is the focal length of the third lens element, v 1  is an Abbe number of the first lens element, v 2  is an Abbe number of the second lens element, T 23  is an axial distance between the second lens element and the third lens element, T 34  is an axial distance between the third lens element and the fourth lens element, R 3  is the curvature radius of the object-side surface of the second lens element, R 4  is the curvature radius of the image-side surface of the second lens element, R 5  is a curvature radius of the object-side surface of the third lens element, R 6  is a curvature radius of the image-side surface of the third lens element, and CT 2  is a central thickness of the second lens element near the optical axis. 
     With the installation of the aforementioned first lens element, second lens element, third lens element and fourth lens element with an appropriate interval apart from one another, the present invention can shorten the total length of the optical lens for image pickup effectively, while providing a good aberration correction and an advantageous modulation transfer function (MTF). 
     In the optical lens for image pickup of the present invention, the first lens element with positive refractive power provides most of the refractive power required by the system that facilitates the reduction of the total length, and the second lens element with negative refractive power can correct aberrations produced by the lens element with positive refractive power effectively and correct the Petzval sum of the system to make the image surface on the edge flatter, and the third lens element and the fourth lens with positive refractive power element can provide the positive refractive power required by the system to reduce the reduce the system&#39;s sensitivity to errors to facilitate the manufacture. In addition, the fourth lens element with positive refractive power can suppress the angle of the light incident into a light sensor, so that the incident angle will not be too large, which helps improving the efficiency of receiving images by the image sensor. 
     In the optical lens for image pickup of the present invention, the stop is a front stop installed between an object to be photographed and the first lens element, or a middle stop installed between the first lens element and the second lens element in order to provide a longer distance between an exit pupil of the optical lens for image pickup and the image plane, so that the light of an image can be projected directly and then received by the image sensor to avoid dark corners or achieve the telecentric effect on the image side. In general, the telecentric effect can improve the brightness of the image plane and enhance the speed of receiving images by the CCD or CMOS image sensor. 
     If the fourth lens element has an inflection point, the inflection point is used for guiding light of an image with an angle out from the edges of the third lens element, such that the light of an image at the off-axis view angle is guided to the image sensor and received by the image sensor. In addition the meniscus third lens element has a concave object-side surface and a convex image-side surface for correcting the astigmatic field curving effectively. In addition, the third lens element and fourth lens element are made of plastic, facilitating the manufacture and lowering the cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic view of an optical lens in accordance with the first preferred embodiment of the present invention; 
         FIG. 1B  is a schematic view of a series of aberration curves of the first preferred embodiment of the present invention; 
         FIG. 2A  is a schematic view of an optical lens in accordance with the second preferred embodiment of the present invention; 
         FIG. 2B  is a schematic view of a series of aberration curves of the second preferred embodiment of the present invention; 
         FIG. 3A  is a schematic view of an optical lens in accordance with the third preferred embodiment of the present invention; 
         FIG. 3B  is a schematic view of a series of aberration curves of the third preferred embodiment of the present invention; 
         FIG. 4A  is a schematic view of an optical lens in accordance with the fourth preferred embodiment of the present invention; 
         FIG. 4B  is a schematic view of a series of aberration curves of the fourth preferred embodiment of the present invention; 
         FIG. 5A  is a schematic view of an optical lens in accordance with the fifth preferred embodiment of the present invention; 
         FIG. 5B  is a schematic view of a series of aberration curves of the fifth preferred embodiment of the present invention; 
         FIG. 6A  is a schematic view of an optical lens in accordance with the sixth preferred embodiment of the present invention; 
         FIG. 6B  is a schematic view of a series of aberration curves of the sixth preferred embodiment of the present invention; 
         FIG. 7A  is a schematic view of an optical lens in accordance with the seventh preferred embodiment of the present invention; 
         FIG. 7B  is a schematic view of a series of aberration curves of the seventh preferred embodiment of the present invention; 
         FIG. 8A  is a schematic view of an optical lens in accordance with the eighth preferred embodiment of the present invention; and 
         FIG. 8B  is a schematic view of a series of aberration curves of the eighth preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIG. 1A  for an optical lens for image pickup of the present invention, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: the first lens element  110 , the second lens element  120 , the third lens element  130  and the fourth lens element  140 , wherein the first lens element  110  with positive refractive power has a convex object-side surface  111 ; the second lens element  120  with negative refractive power has a convex object-side surface  121  and a concave image-side surface  122 ; the plastic third lens element  130  with positive refractive power has a concave object-side surface  131  and a convex image-side surface  132 , and both object-side surface  131  and image-side surface  132  are aspheric; and the plastic fourth lens element  140  with positive refractive power has a convex object-side surface  141  and a concave image-side surface  142 , and both object-side surface  141  and image-side surface  142  thereof are aspheric; and the optical lens for image pickup further comprises a stop, which can be an aperture stop  100  and an IR-filter  160 , wherein the aperture stop  100  is a middle aperture stop installed between the first lens element  110  and the second lens element  120 ; the IR-filter  160  is installed between the fourth lens element  140  and the image plane  170  and generally made of panel glass without affecting the focal length f of the optical lens for image pickup of the present invention. The optical lens for image pickup further comprises an image sensor  180  at an image plane  170  for imaging an object to be photographed. The first lens element  110 , second lens element  120 , third lens element  130  and fourth lens element  140  have aspherical surfaces, and comply with the aspherical surface formula as given in Equation (15). 
     
       
         
           
             
               
                 
                   
                     X 
                     ⁡ 
                     
                       ( 
                       Y 
                       ) 
                     
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             Y 
                             2 
                           
                           / 
                           R 
                         
                         ) 
                       
                       
                         1 
                         + 
                         
                           
                             ( 
                             
                               1 
                               - 
                               
                                 
                                   ( 
                                   
                                     1 
                                     + 
                                     K 
                                   
                                   ) 
                                 
                                 ⁢ 
                                 
                                   
                                     ( 
                                     
                                       Y 
                                       / 
                                       R 
                                     
                                     ) 
                                   
                                   2 
                                 
                               
                             
                             ) 
                           
                         
                       
                     
                     + 
                     
                       
                         ∑ 
                         i 
                       
                       ⁢ 
                       
                         
                           ( 
                           
                             A 
                             i 
                           
                           ) 
                         
                         · 
                         
                           ( 
                           
                             Y 
                             i 
                           
                           ) 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   15 
                   ) 
                 
               
             
           
         
       
     
     Wherein, X is the relative height from a point on the spherical surface with a distance Y between the optical axis and a tangent plane at the tip of the optical axis of the spherical surface; 
     Y is the distance between a point on the curve of the spherical surface and the optical axis; 
     R is the curvature radius; 
     K is the conic coefficient; and 
     A i  is the i tch  level aspherical surface coefficient. 
     In the optical lens for image pickup of the present invention, the first lens element  110 , second lens element  120 , third lens element  130  and fourth lens element  140  can be spherical or aspherical surfaces, and if aspherical optical surfaces are adopted, then curvature radius of the optical surface can be used for changing the refractive power to reduce or eliminate aberrations, so as to decrease the number of lens elements used in the optical lens for image pickup, and shorten the total length of the optical lens for image pickup effectively. With the installation of the first lens element  110 , second lens element  120 , third lens element  130  and fourth lens element  140 , the optical lens for image pickup of the present invention satisfies the relations (1), (2) and (3). 
     In the optical lens for image pickup of the present invention, the second lens element  120  provides the main negative refractive power, and if the relation (3) is satisfied, the image-side surface  122  has a more appropriate curvature radius for improving the aberration correction ability. If the relation (1) is satisfied, the curvature of the object-side surface  121  and the image-side surface  122  of the second lens element  120  can limit the change of the shape of the second lens element  120  to facilitate the manufacture and lower the cost. Similarly, if the curvature of the third lens element  130  satisfies the relation (2), the change of the shape of the third lens element  130  can be limited to a condition of being not too large to facilitate the manufacture and lower the cost. If the curvature of the fourth lens element  140  satisfies the relation (4), the shape can be controlled to adjust the refractive power of the fourth lens element  140  appropriately to reduce the system&#39;s sensitivity to errors and facilitate the manufacture and lower the cost. 
     In the optical lens for image pickup of the present invention, if the relations (7) and (8) are satisfied, wherein f is the focal length of the optical lens for image pickup, f 2  is the focal length of the second lens element  120 , f 3  is the focal length of the third lens element  130 , and appropriate refractive powers are allocated in the optical lens for image pickup, the refractive powers required by the second lens element  120  and the third lens element  130  can correct the system aberration and reduce the system&#39;s sensitivity to errors. 
     If the relations (9) and (11) are satisfied, the distance between the first lens element  110  and the fourth lens element  140  can be limited to set the optical lens for image pickup to an appropriate length. Similarly, if the relation (12) is satisfied, the focal length of the optical lens for image pickup per unit length can adjust the central thickness CT 2  of the second lens element  120  to reduce the total length of the optical lens for image pickup and provide an appropriate thickness of the second lens element  120 , so as to improve the yield rate of the lenses. If the relation (13) is satisfied, the total length of the optical lens for image pickup can be reduced effectively, such that a larger effective pixel range of the image sensor  180  can be achieved in the same total length to facilitate adjusting the total length of the system appropriately. 
     If the relations (5) and (14) are satisfied, the difference between the Abbe number v 1  of the first lens element  110  and the Abbe number v 2  of the second lens element  120  falls within an appropriate range to correct the chromic aberration produced by the first lens element  110  and the second lens element  120  and improve the chromic aberration correction ability of the second lens element  120 . If the relation (10) is satisfied, the shape of the object-side surface  111  of the first lens element  110  can provide appropriate positive refractive power to the system, and achieve a good result of reducing the total length of the system. 
     The optical lens for image pickup of the present invention is described by means of preferred embodiments with relevant drawings as follows. 
     First Preferred Embodiment 
     With reference to  FIGS. 1A and 1B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the first preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, a stop and an IR-filter  160 . More specifically, the stop can be an aperture stop  100 , and the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  110  with positive refractive power, having a convex object-side surface  111  and a concave image-side surface  112 , and both object-side surface  111  and image-side surface  112  thereof being aspheric; an aperture stop  100 ; a plastic second lens element  120  with negative refractive power, having a convex object-side surface  121  and a concave image-side surface  122 , and both object-side surface  121  and image-side surface  122  thereof being aspheric; a plastic third lens element  130  with positive refractive power, having a concave object-side surface  131  and a convex image-side surface  132 , and both object-side surface  131  and image-side surface  132  thereof being aspheric; a plastic fourth lens element  140  with positive refractive power, having a convex object-side surface  141  and a concave image-side surface  142 , and both object-side surface  141  and image-side surface  142  thereof being aspheric, and at least one of the object-side surface  141  and the image-side surface  142  having at least one inflection point; a glass IR-filter  160 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  180  at an image plane  170 . With the combination of the four lens elements, the aperture stop  100  and the IR-filter  160 , an image of the object to be photographed can be formed at the image sensor  180 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.46 mm, Fno = 2.85, HFOV = 33.1 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.264190 (ASP) 
                 0.491 
                 Plastic 
                 1.544 
                 55.9 
                 2.34 
               
               
                 2 
                   
                 120.243100 (ASP)  
                 0.014 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.025 
               
               
                 4 
                 Lens 2 
                 2.960060 (ASP) 
                 0.230 
                 Plastic 
                 1.634 
                 23.8 
                 −3.45 
               
               
                 5 
                 t 
                 1.220770 (ASP) 
                 0.573 
               
               
                 6 
                 Lens 3 
                 −2.250110 (ASP)  
                 0.490 
                 Plastic 
                 1.544 
                 55.9 
                 13.17 
               
               
                 7 
                   
                 −1.843720 (ASP)  
                 0.561 
               
               
                 8 
                 Lens 4 
                 1.395250 (ASP) 
                 0.620 
                 Plastic 
                 1.535 
                 56.3 
                 101.56 
               
               
                 9 
                   
                 1.210370 (ASP) 
                 0.600 
               
               
                 10 
                 IR filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.286 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 1, wherein the object-side surface and the image-side surface of the first lens element  110  to the fourth lens element  140  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 2 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
                   
               
             
          
           
               
                 k = 
                 7.82987E−02 
                 −9.00000E+01 
                 −5.41536E+01 
                 1.26500E+00 
                 −2.91680E+00 
                 −8.67362E−17 
                 −5.05901E+00 
                 −3.86689E+00 
               
               
                 A4 = 
                 2.61065E−02 
                 6.78884E−02 
                 9.31128E−02 
                 −2.59320E−01 
                 −2.54378E−01 
                 −3.43460E−01 
                 −2.29723E−01 
                 −1.53736E−01 
               
               
                 A6 = 
                 5.82074E−02 
                 1.30933E−01 
                 −3.06327E−01 
                 2.47180E−01 
                 1.33068E−01 
                 3.81332E−01 
                 1.04423E−01 
                 6.81514E−02 
               
               
                 A8 = 
                 −3.10968E−02 
                 −3.17567E−01 
                 4.50480E−01 
                 −5.43126E−01 
                 −2.90132E−01 
                 −4.31906E−01 
                 −2.14275E−02 
                 −2.56022E−02 
               
               
                 A10 = 
                 1.56738E−01 
                 1.29058E−01 
                 −9.63772E−01 
                 2.06125E−01 
                 2.47359E−01 
                 2.20149E−01 
                 4.59681E−04 
                 6.33113E−03 
               
               
                 A12 = 
                   
                   
                   
                 −3.20713E−01 
                 2.32524E−01 
                   
                 7.07566E−04 
                 −9.76275E−04 
               
               
                 A14 = 
                   
                   
                   
                   
                   
                   
                 −9.32850E−05 
                 7.64832E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 1 and  FIG. 1B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.46 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.85, the half of maximum view angle is HFOV=33.1°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 3 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 32.1 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.42 
               
               
                   
                 (CT 2 /f) * 10 
                 0.66 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.10 
               
               
                   
                 T 12 /T 23   
                 0.07 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.07 
               
               
                   
                 T 23 /T 34   
                 1.02 
                 f/f 3   
                 0.26 
               
               
                   
                 R 1 /f 
                 0.37 
                 |f 2 |/f 3   
                 0.26 
               
               
                   
                 R 4 /f 
                 0.35 
                 TTL/ImgH 
                 1.80 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 1 and the aberration curves as shown in  FIG. 1B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Second Preferred Embodiment 
     With reference to  FIGS. 2A and 2B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the second preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  200  and an IR-filter  260 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  210  with positive refractive power, having a convex object-side surface  211  and a convex image-side surface  212 , and both object-side surface  211  and image-side surface  212  thereof being aspheric; an aperture stop  200 ; a plastic second lens element  220  with negative refractive power, having a convex object-side surface  221  and a concave image-side surface  222 , and both object-side surface  221  and image-side surface  222  thereof being aspheric; a plastic third lens element  230  with positive refractive power, having a concave object-side surface  231  and a convex image-side surface  232 , and both object-side surface  231  and image-side surface  232  thereof being aspheric; a plastic fourth lens element  240  with positive refractive power, having a convex object-side surface  241  and a concave image-side surface  242 , and both object-side surface  241  and image-side surface  242  thereof being aspheric, and at least one of the object-side surface  241  and the image-side surface  242  having at least one inflection point; a glass IR-filter  260 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  280  at an image plane  270 . With the combination of the four lens elements, the aperture stop  200  and the IR-filter  260 , an image of the object to be photographed can be formed at the image sensor  280 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.90 mm, Fno = 2.80, HFOV = 30.1 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.252630 
                 0.545 
                 Plastic 
                 1.544 
                 55.9 
                 2.30 
               
               
                   
                   
                 (ASP) 
               
               
                 2 
                   
                 −802.438600   
                 0.040 
               
               
                   
                   
                 (ASP) 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.009 
               
               
                 4 
                 Lens 2 
                 3.581200 
                 0.244 
                 Plastic 
                 1.634 
                 23.8 
                 −3.32 
               
               
                   
                   
                 (ASP) 
               
               
                 5 
                   
                 1.291490 
                 0.912 
               
               
                   
                   
                 (ASP) 
               
               
                 6 
                 Lens 3 
                 −1.178490  
                 0.474 
                 Plastic 
                 1.544 
                 55.9 
                 16.10 
               
               
                   
                   
                 (ASP) 
               
               
                 7 
                   
                 −1.185980  
                 0.208 
               
               
                   
                   
                 (ASP) 
               
               
                 8 
                 Lens 4 
                 2.262390 
                 0.822 
                 Plastic 
                 1.535 
                 56.3 
                 113.05 
               
               
                   
                   
                 (ASP) 
               
               
                 9 
                   
                 2.052880 
                 0.700 
               
               
                   
                   
                 (ASP) 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.353 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 4, wherein the object-side surface and the image-side surface of the first lens element  210  to the fourth lens element  240  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 5 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 1.12630E−01 
                 −9.00000E+01 
                 −4.74807E+01 
                 1.35881E+00 
               
               
                 A4 = 
                 1.40822E−02 
                 1.15980E−01 
                 8.98965E−02 
                 −1.52792E−01 
               
               
                 A6 = 
                 4.63013E−02 
                 −1.90874E−01 
                 −3.59422E−01 
                 4.45040E−02 
               
               
                 A8 = 
                 −5.44994E−02 
                 4.08106E−01 
                 6.43161E−01 
                 −1.18160E−01 
               
               
                 A10 = 
                 1.24001E−01 
                 −4.23253E−01 
                 −8.33351E−01 
                 1.02575E−01 
               
               
                 A12 = 
                   
                   
                   
                 −3.12074E−01 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −4.99634E+00 
                 −2.00000E−02 
                 −2.12128E+01 
                 −1.38235E+00 
               
               
                 A4 = 
                 −4.18192E−01 
                 −2.05978E−01 
                 −1.19587E−01 
                 −1.71564E−01 
               
               
                 A6 = 
                 8.24730E−02 
                 2.81896E−01 
                 7.94066E−02 
                 6.79844E−02 
               
               
                 A8 = 
                 −1.43683E−01 
                 −3.08773E−01 
                 −2.30659E−02 
                 −2.39703E−02 
               
               
                 A10 = 
                 1.85547E−01 
                 1.94282E−01 
                 9.42736E−04 
                 6.05816E−03 
               
               
                 A12 = 
                 1.19482E−01 
                   
                 7.87833E−04 
                 −1.00568E−03 
               
               
                 A14 = 
                   
                   
                 −1.07245E−04 
                 7.74255E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 4 and  FIG. 2B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.90 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.80, the half of maximum view angle is HFOV=30.1°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 6 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 32.1 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.47 
               
               
                   
                 (CT 2 /f) * 10 
                 0.63 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.00 
               
               
                   
                 T 12 /T 23   
                 0.05 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.05 
               
               
                   
                 T 23 /T 34   
                 4.38 
                 f/f 3   
                 0.24 
               
               
                   
                 R 1 /f 
                 0.32 
                 |f 2 |/f 3   
                 0.21 
               
               
                   
                 R 4 /f 
                 0.33 
                 TTL/ImgH 
                 1.99 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 4 and the aberration curves as shown in  FIG. 2B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Third Preferred Embodiment 
     With reference to  FIGS. 3A and 3B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the third preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  300  and an IR-filter  360 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  310  with positive refractive power, having a convex object-side surface  311  and a concave image-side surface  312 , and both object-side surface  311  and image-side surface  312  thereof being aspheric; an aperture stop  300 ; a plastic second lens element  320  with negative refractive power, having a convex object-side surface  321  and a concave image-side surface  322 , and both object-side surface  321  and image-side surface  322  thereof being aspheric; a plastic third lens element  330  with positive refractive power, having a concave object-side surface  331  and a convex image-side surface  332 , and both object-side surface  331  and image-side surface  332  thereof being aspheric; a plastic fourth lens element  340  with positive refractive power, having a convex object-side surface  341  and a concave image-side surface  342 , and both object-side surface  341  and image-side surface  342  thereof being aspheric, and at least one of the object-side surface  341  and the image-side surface  342  having at least one inflection point; a glass IR-filter  360 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  380  at an image plane  370 . With the combination of the four lens elements, the aperture stop  300  and the IR-filter  360 , an image of the object to be photographed can be formed at the image sensor  380 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 7 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.38 mm, Fno = 2.90, HFOV = 34.0 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.325890 (ASP) 
                 0.461 
                 Plastic 
                 1.544 
                 55.9 
                 2.65 
               
               
                 2 
                   
                 14.275000 (ASP)  
                 0.050 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.020 
               
               
                 4 
                 Lens 2 
                 2.413980 (ASP) 
                 0.230 
                 Plastic 
                 1.650 
                 21.4 
                 −4.44 
               
               
                 5 
                   
                 1.265240 (ASP) 
                 0.544 
               
               
                 6 
                 Lens 3 
                 −2.264850 (ASP)  
                 0.512 
                 Plastic 
                 1.544 
                 55.9 
                 15.32 
               
               
                 7 
                   
                 −1.922790 (ASP)  
                 0.521 
               
               
                 8 
                 Lens 4 
                 1.261510 (ASP) 
                 0.632 
                 Plastic 
                 1.535 
                 56.3 
                 34.13 
               
               
                 9 
                   
                 1.118700 (ASP) 
                 0.600 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.303 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 7, wherein the object-side surface and the image-side surface of the first lens element  310  to the fourth lens element  340  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 8 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 8 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 −1.06828E−02 
                 −3.40769E+01 
                 −3.26928E+01 
                 1.63897E+00 
               
               
                 A4 = 
                 2.23769E−02 
                 −3.48808E−02 
                 7.72565E−02 
                 −2.52437E−01 
               
               
                 A6 = 
                 2.27375E−02 
                 2.72496E−01 
                 −2.22905E−01 
                 2.24639E−01 
               
               
                 A8 = 
                 4.35646E−02 
                 −5.49380E−01 
                 3.81232E−01 
                 −6.89445E−01 
               
               
                 A10 = 
                 −1.56208E−02 
                 3.64034E−01 
                 −7.20717E−01 
                 7.42416E−01 
               
               
                 A12 = 
                   
                   
                   
                 −1.27804E+00 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −2.35841E+00 
                 −3.58077E−02 
                 −5.00438E+00 
                 −3.97936E+00 
               
               
                 A4 = 
                 −2.63179E−01 
                 −4.06146E−01 
                 −2.37944E−01 
                 −1.50752E−01 
               
               
                 A6 = 
                 1.39406E−01 
                 4.78663E−01 
                 1.08376E−01 
                 6.63485E−02 
               
               
                 A8 = 
                 −3.34010E−01 
                 −5.43624E−01 
                 −2.13673E−02 
                 −2.53286E−02 
               
               
                 A10 = 
                 1.82712E−01 
                 2.62151E−01 
                 2.89959E−04 
                 6.39604E−03 
               
               
                 A12 = 
                 4.12067E−01 
                   
                 6.69087E−04 
                 −1.00129E−03 
               
               
                 A14 = 
                   
                   
                 −8.17958E−05 
                 7.79899E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 7 and  FIG. 3B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.38 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.90, the half of maximum view angle is HFOV=34.0°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 9 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 9 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 34.5 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.31 
               
               
                   
                 (CT 2 /f) * 10 
                 0.68 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.08 
               
               
                   
                 T 12 /T 23   
                 0.13 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.06 
               
               
                   
                 T 23 /T 34   
                 1.04 
                 f/f 3   
                 0.22 
               
               
                   
                 R 1 /f 
                 0.39 
                 |f 2 |/f 3   
                 0.29 
               
               
                   
                 R 4 /f 
                 0.37 
                 TTL/ImgH 
                 1.80 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 7 and the aberration curves as shown in  FIG. 3B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Fourth Preferred Embodiment 
     With reference to  FIGS. 4A and 4B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the fourth preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  400  and an IR-filter  460 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  410  with positive refractive power, having a convex object-side surface  411  and a convex image-side surface  412 , and both object-side surface  411  and image-side surface  412  thereof being aspheric; an aperture stop  400 ; a plastic second lens element  420  with negative refractive power, having a convex object-side surface  421  and a concave image-side surface  422 , and both object-side surface  421  and image-side surface  422  thereof being aspheric; a plastic third lens element  430  with positive refractive power, having a concave object-side surface  431  and a convex image-side surface  432 , and both object-side surface  431  and image-side surface  432  thereof being aspheric; a plastic fourth lens element  440  with positive refractive power, having a convex object-side surface  441  and a concave image-side surface  442 , and both object-side surface  441  and image-side surface  442  thereof being aspheric, and at least one of the object-side surface  441  and the image-side surface  442  having at least one inflection point; a glass IR-filter  460 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  480  at an image plane  470 . With the combination of the four lens elements, the aperture stop  400  and the IR-filter  460 , an image of the object to be photographed can be formed at the image sensor  480 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 10 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.33 mm, Fno = 2.90, HFOV = 34.5 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.451360 (ASP) 
                 0.438 
                 Plastic 
                 1.544 
                 55.9 
                 2.58 
               
               
                 2 
                   
                 −38.610000 (ASP)  
                 0.004 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.077 
               
               
                 4 
                 Lens 2 
                 2.646890 (ASP) 
                 0.230 
                 Plastic 
                 1.650 
                 21.4 
                 −4.36 
               
               
                 5 
                   
                 1.321460 (ASP) 
                 0.527 
               
               
                 6 
                 Lens 3 
                 −2.147130 (ASP)  
                 0.488 
                 Plastic 
                 1.544 
                 55.9 
                 16.42 
               
               
                 7 
                   
                 −1.869780 (ASP)  
                 0.541 
               
               
                 8 
                 Lens 4 
                 1.152470 (ASP) 
                 0.590 
                 Plastic 
                 1.535 
                 56.3 
                 33.08 
               
               
                 9 
                   
                 1.012950 (ASP) 
                 0.600 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.327 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 10, wherein the object-side surface and the image-side surface of the first lens element  410  to the fourth lens element  440  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 11 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 11 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 −3.67979E−01 
                 −7.03192E+01 
                 −3.59980E+01 
                 1.90425E+00 
               
               
                 A4 = 
                 6.94373E−03 
                 −7.62775E−02 
                 6.03080E−02 
                 −2.44677E−01 
               
               
                 A6 = 
                 −4.72389E−02 
                 2.39718E−01 
                 −1.64776E−02 
                 3.17974E−01 
               
               
                 A8 = 
                 1.14364E−01 
                 −7.12219E−01 
                 −1.41610E−02 
                 −9.42666E−01 
               
               
                 A10 = 
                 −2.80084E−01 
                 5.21979E−01 
                 −1.61531E−01 
                 1.40655E+00 
               
               
                 A12 = 
                   
                   
                   
                 −1.96482E+00 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −1.63603E+00 
                 −5.19970E−04 
                 −4.71886E+00 
                 −3.93956E+00 
               
               
                 A4 = 
                 −3.11333E−01 
                 −4.59108E−01 
                 −2.45437E−01 
                 −1.52632E−01 
               
               
                 A6 = 
                 1.95510E−01 
                 6.05835E−01 
                 1.11920E−01 
                 6.81965E−02 
               
               
                 A8 = 
                 −4.61335E−01 
                 −7.60033E−01 
                 −2.13107E−02 
                 −2.57787E−02 
               
               
                 A10 = 
                 1.34454E−01 
                 4.03991E−01 
                 1.41859E−04 
                 6.48915E−03 
               
               
                 A12 = 
                 7.96772E−01 
                   
                 6.38335E−04 
                 −1.01321E−03 
               
               
                 A14 = 
                   
                   
                 −7.21936E−05 
                 7.84630E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 10 and  FIG. 4B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.33 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.90, the half of maximum view angle is HFOV=34.5°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 12 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 12 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 34.5 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.33 
               
               
                   
                 (CT 2 /f) * 10 
                 0.69 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.07 
               
               
                   
                 T 12 /T 23   
                 0.15 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.06 
               
               
                   
                 T 23 /T 34   
                 0.97 
                 f/f 3   
                 0.20 
               
               
                   
                 R 1 /f 
                 0.44 
                 |f 2 |/f 3   
                 0.27 
               
               
                   
                 R 4 /f 
                 0.40 
                 TTL/ImgH 
                 1.78 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 10 and the aberration curves as shown in  FIG. 4B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Fifth Preferred Embodiment 
     With reference to  FIGS. 5A and 5B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the fifth preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  500  and an IR-filter  560 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  510  with positive refractive power, having a convex object-side surface  511  and a convex image-side surface  512 , and both object-side surface  511  and image-side surface  512  thereof being aspheric; an aperture stop  500 ; a plastic second lens element  520  with negative refractive power, having a convex object-side surface  521  and a concave image-side surface  522 , and both object-side surface  521  and image-side surface  522  thereof being aspheric; a plastic third lens element  530  with positive refractive power, having a concave object-side surface  531  and a convex image-side surface  532 , and both object-side surface  531  and image-side surface  532  thereof being aspheric; a plastic fourth lens element  540  with positive refractive power, having a convex object-side surface  541  and a concave image-side surface  542 , and both object-side surface  541  and image-side surface  542  thereof being aspheric, and at least one of the object-side surface  541  and the image-side surface  542  having at least one inflection point; a glass IR-filter  560 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  580  at an image plane  570 . With the combination of the four lens elements, the aperture stop  500  and the IR-filter  560 , an image of the object to be photographed can be formed at the image sensor  580 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 13 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.13 mm, Fno = 2.92, HFOV = 36.1 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.504790 (ASP) 
                 0.392 
                 Plastic 
                 1.544 
                 55.9 
                 2.54 
               
               
                 2 
                   
                 −15.463300 (ASP)  
                 0.000 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.095 
               
               
                 4 
                 Lens 2 
                 3.002200 (ASP) 
                 0.230 
                 Plastic 
                 1.650 
                 21.4 
                 −4.33 
               
               
                 5 
                   
                 1.407730 (ASP) 
                 0.498 
               
               
                 6 
                 Lens 3 
                 −2.016070 (ASP)  
                 0.518 
                 Plastic 
                 1.544 
                 55.9 
                 12.20 
               
               
                 7 
                   
                 −1.686360 (ASP)  
                 0.504 
               
               
                 8 
                 Lens 4 
                 0.898130 (ASP) 
                 0.461 
                 Plastic 
                 1.535 
                 56.3 
                 29.08 
               
               
                 9 
                   
                 0.782760 (ASP) 
                 0.700 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.272 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 13, wherein the object-side surface and the image-side surface of the first lens element  510  to the fourth lens element  540  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 14 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 14 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 −5.77288E−01 
                 −7.71819E+01 
                 −2.07552E+01 
                 2.52529E+00 
               
               
                 A4 = 
                 −2.86605E−03 
                 −4.84015E−02 
                 1.70870E−02 
                 −1.84313E−01 
               
               
                 A6 = 
                 −7.40912E−02 
                 −2.04905E−02 
                 1.24401E−02 
                 1.80039E−01 
               
               
                 A8 = 
                 1.08651E−01 
                 −4.65126E−01 
                 −2.16253E−01 
                 −1.06982E+00 
               
               
                 A10 = 
                 −5.33183E−01 
                 3.69782E−01 
                 1.59852E−01 
                 2.16711E+00 
               
               
                 A12 = 
                   
                   
                   
                 −3.10136E+00 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −1.01966E+00 
                 −1.70971E−03 
                 −4.16589E+00 
                 −3.65374E+00 
               
               
                 A4 = 
                 −2.76894E−01 
                 −4.92814E−01 
                 −2.62394E−01 
                 −1.65660E−01 
               
               
                 A6 = 
                 1.70832E−01 
                 7.62946E−01 
                 1.15773E−01 
                 7.15984E−02 
               
               
                 A8 = 
                 −5.55414E−01 
                 −9.98371E−01 
                 −2.10067E−02 
                 −2.60721E−02 
               
               
                 A10 = 
                 2.84243E−01 
                 5.27915E−01 
                 2.54852E−05 
                 6.44296E−03 
               
               
                 A12 = 
                 8.72022E−01 
                   
                 6.07347E−04 
                 −1.04292E−03 
               
               
                 A14 = 
                   
                   
                 −6.41574E−05 
                 8.93790E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 13 and  FIG. 5B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.13 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.92, the half of maximum view angle is HFOV=36.1°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 15 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 15 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 34.5 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.36 
               
               
                   
                 (CT 2 /f) * 10 
                 0.73 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.09 
               
               
                   
                 T 12 /T 23   
                 0.19 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.07 
               
               
                   
                 T 23 /T 34   
                 0.99 
                 f/f 3   
                 0.26 
               
               
                   
                 R 1 /f 
                 0.48 
                 |f 2 |/f 3   
                 0.36 
               
               
                   
                 R 4 /f 
                 0.45 
                 TTL/ImgH 
                 1.71 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 13 and the aberration curves as shown in  FIG. 5B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Sixth Preferred Embodiment 
     With reference to  FIGS. 6A and 6B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the sixth preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  600  and an IR-filter  660 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: an aperture stop  600 ; a plastic first lens element  610  with positive refractive power, having a convex object-side surface  611  and a convex image-side surface  612 , and both object-side surface  611  and image-side surface  612  thereof being aspheric; a plastic second lens element  620  with negative refractive power, having a convex object-side surface  621  and a concave image-side surface  622 , and both object-side surface  621  and image-side surface  622  thereof being aspheric; a plastic third lens element  630  with positive refractive power, having a concave object-side surface  631  and a convex image-side surface  632 , and both object-side surface  631  and image-side surface  632  thereof being aspheric; a plastic fourth lens element  640  with positive refractive power, having a convex object-side surface  641  and a concave image-side surface  642 , and both object-side surface  641  and image-side surface  642  thereof being aspheric, and at least one of the object-side surface  641  and the image-side surface  642  having at least one inflection point; a glass IR-filter  660 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  680  at an image plane  670 . With the combination of the four lens elements, the aperture stop  600  and the IR-filter  660 , an image of the object to be photographed can be formed at the image sensor  680 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 16 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.52 mm, Fno = 3.10, HFOV = 30.1 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 0.030 
               
               
                 2 
                 Lens 1 
                 1.269040 (ASP) 
                 0.542 
                 Plastic 
                 1.544 
                 55.9 
                 2.20 
               
               
                 3 
                   
                 −17.654900 (ASP)  
                 0.043 
               
               
                 4 
                 Lens 2 
                 4.209000 (ASP) 
                 0.262 
                 Plastic 
                 1.634 
                 23.8 
                 −3.21 
               
               
                 5 
                   
                 1.338070 (ASP) 
                 0.827 
               
               
                 6 
                 Lens 3 
                 −1.156260 (ASP)  
                 0.462 
                 Plastic 
                 1.544 
                 55.9 
                 15.57 
               
               
                 7 
                   
                 −1.160640 (ASP)  
                 0.073 
               
               
                 8 
                 Lens 4 
                 1.907350 (ASP) 
                 0.848 
                 Plastic 
                 1.535 
                 56.3 
                 48.28 
               
               
                 9 
                   
                 1.740550 (ASP) 
                 0.600 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.342 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 16, wherein the object-side surface and the image-side surface of the first lens element  610  to the fourth lens element  640  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 17 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 17 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 2 
                 3 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 1.08487E−01 
                 1.09160E+01 
                 −6.86181E+01 
                 1.39208E+00 
               
               
                 A4 = 
                 1.23667E−02 
                 1.25563E−01 
                 7.81655E−02 
                 −1.66858E−01 
               
               
                 A6 = 
                 5.02354E−02 
                 −1.68618E−01 
                 −3.71282E−01 
                 2.92660E−02 
               
               
                 A8 = 
                 −4.22649E−02 
                 3.35539E−01 
                 6.82379E−01 
                 −1.12341E−01 
               
               
                 A10 = 
                 7.55568E−02 
                 −5.01309E−01 
                 −9.28099E−01 
                 1.12411E−01 
               
               
                 A12 = 
                   
                   
                   
                 −1.99796E−01 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −6.63866E+00 
                 −2.00000E−02 
                 −1.73669E+01 
                 −2.97618E+00 
               
               
                 A4 = 
                 −3.91677E−01 
                 −1.67689E−01 
                 −1.13032E−01 
                 −1.61659E−01 
               
               
                 A6 = 
                 1.06669E−01 
                 2.93687E−01 
                 7.95613E−02 
                 6.88713E−02 
               
               
                 A8 = 
                 −1.50341E−01 
                 −3.05916E−01 
                 −2.31699E−02 
                 −2.41566E−02 
               
               
                 A10 = 
                 1.25524E−01 
                 1.95476E−01 
                 8.97848E−04 
                 6.01285E−03 
               
               
                 A12 = 
                 6.54579E−02 
                   
                 7.81834E−04 
                 −1.00775E−03 
               
               
                 A14 = 
                   
                   
                 −1.04900E−04 
                 7.84643E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 16 and  FIG. 6B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.52 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=3.10, the half of maximum view angle is HFOV=30.1°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 18 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 18 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 32.1 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.52 
               
               
                   
                 (CT 2 /f) * 10 
                 0.74 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.00 
               
               
                   
                 T 12 /T 23   
                 0.05 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.05 
               
               
                   
                 T 23 /T 34   
                 11.33 
                 f/f 3   
                 0.23 
               
               
                   
                 R 1 /f 
                 0.36 
                 |f 2 |/f 3   
                 0.21 
               
               
                   
                 R 4 /f 
                 0.38 
                 TTL/ImgH 
                 2.06 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 16 and the aberration curves as shown in  FIG. 6B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Seventh Preferred Embodiment 
     With reference to  FIGS. 7A and 7B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the seventh preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  700  and an IR-filter  760 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  710  with positive refractive power, having a convex object-side surface  711  and a concave image-side surface  712 , and both object-side surface  711  and image-side surface  712  thereof being aspheric; an aperture stop  700 ; a plastic second lens element  720  with negative refractive power, having a convex object-side surface  721  and a concave image-side surface  722 , and both object-side surface  721  and image-side surface  722  thereof being aspheric; a plastic third lens element  730  with positive refractive power, having a concave object-side surface  731  and a convex image-side surface  732 , and both object-side surface  731  and image-side surface  732  thereof being aspheric; a plastic fourth lens element  740  with positive refractive power, having a convex object-side surface  741  and a concave image-side surface  742 , and both object-side surface  741  and image-side surface  742  thereof being aspheric, and at least one of the object-side surface  741  and the image-side surface  742  having at least one inflection point; a glass IR-filter  760 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  780  at an image plane  770 . With the combination of the four lens elements, the aperture stop  700  and the IR-filter  760 , an image of the object to be photographed can be formed at the image sensor  780 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 19 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.42 mm, Fno = 2.87, HFOV = 33.3 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.267150 (ASP) 
                 0.494 
                 Plastic 
                 1.544 
                 55.9 
                 2.56 
               
               
                 2 
                   
                 12.123900 (ASP)  
                 0.040 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.001 
               
               
                 4 
                 Lens 2 
                 2.338050 (ASP) 
                 0.230 
                 Plastic 
                 1.650 
                 21.4 
                 −4.25 
               
               
                 5 
                   
                 1.216840 (ASP) 
                 0.577 
               
               
                 6 
                 Lens 3 
                 −2.119960 (ASP)  
                 0.509 
                 Plastic 
                 1.544 
                 55.9 
                 27.82 
               
               
                 7 
                   
                 −2.016900 (ASP)  
                 0.490 
               
               
                 8 
                 Lens 4 
                 1.299860 (ASP) 
                 0.667 
                 Plastic 
                 1.535 
                 56.3 
                 19.15 
               
               
                 9 
                   
                 1.222780 (ASP) 
                 0.700 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.190 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 19, wherein the object-side surface and the image-side surface of the first lens element  710  to the fourth lens element  740  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 20 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 20 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 4.58604E−02 
                 −9.00000E+01 
                 −2.99746E+01 
                 1.55375E+00 
               
               
                 A4 = 
                 2.63530E−02 
                 1.54046E−02 
                 1.09842E−01 
                 −2.46683E−01 
               
               
                 A6 = 
                 5.69786E−02 
                 2.51590E−01 
                 −2.97333E−01 
                 1.40807E−01 
               
               
                 A8 = 
                 −3.60552E−02 
                 −5.39697E−01 
                 4.12053E−01 
                 −5.69070E−01 
               
               
                 A10 = 
                 1.38319E−01 
                 3.58142E−01 
                 −8.61873E−01 
                 4.48754E−01 
               
               
                 A12 = 
                   
                   
                   
                 −1.15754E+00 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −2.16341E+00 
                 −5.82157E−17 
                 −4.97536E+00 
                 −3.77390E+00 
               
               
                 A4 = 
                 −2.62391E−01 
                 −4.17918E−01 
                 −2.30419E−01 
                 −1.53100E−01 
               
               
                 A6 = 
                 1.40768E−01 
                 4.82330E−01 
                 1.06331E−01 
                 6.70517E−02 
               
               
                 A8 = 
                 −3.21112E−01 
                 −5.21093E−01 
                 −2.15663E−02 
                 −2.53109E−02 
               
               
                 A10 = 
                 1.49153E−01 
                 2.44507E−01 
                 3.50709E−04 
                 6.37677E−03 
               
               
                 A12 = 
                 4.25407E−01 
                   
                 6.87662E−04 
                 −9.92470E−04 
               
               
                 A14 = 
                   
                   
                 −8.59280E−05 
                 7.57729E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 19 and  FIG. 7B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.42 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.87, the half of maximum view angle is HFOV=33.3°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 21 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 21 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 34.5 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.32 
               
               
                   
                 (CT 2 /f) * 10 
                 0.67 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.02 
               
               
                   
                 T 12 /T 23   
                 0.07 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.03 
               
               
                   
                 T 23 /T 34   
                 1.18 
                 f/f 3   
                 0.12 
               
               
                   
                 R 1 /f 
                 0.37 
                 |f 2 |/f 3   
                 0.15 
               
               
                   
                 R 4 /f 
                 0.36 
                 TTL/ImgH 
                 1.81 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 19 and the aberration curves as shown in  FIG. 7B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     Eighth Preferred Embodiment 
     With reference to  FIGS. 8A and 8B  for a schematic view and a series of aberration curves of an optical lens for image pickup in accordance with the eighth preferred embodiment of the present invention respectively, the optical lens for image pickup of this preferred embodiment comprises four lens elements, an aperture stop  800  and an IR-filter  860 . More specifically, the optical lens for image pickup, sequentially arranged from an object side to an image side along an optical axis, comprises: a plastic first lens element  810  with positive refractive power, having a convex object-side surface  811  and a concave image-side surface  812 , and both object-side surface  811  and image-side surface  812  thereof being aspheric; an aperture stop  800 ; a plastic second lens element  820  with negative refractive power, having a convex object-side surface  821  and a concave image-side surface  822 , and both object-side surface  821  and image-side surface  822  thereof being aspheric; a plastic third lens element  830  with positive refractive power, having a concave object-side surface  831  and a convex image-side surface  832 , and both object-side surface  831  and image-side surface  832  thereof being aspheric; a plastic fourth lens element  840  with positive refractive power, having a convex object-side surface  841  and a concave image-side surface  842 , and both object-side surface  841  and image-side surface  842  thereof being aspheric, and at least one of the object-side surface  841  and the image-side surface  842  having at least one inflection point; a glass IR-filter  860 , being made of a panel glass for adjusting a wavelength section of the light of an image; and an image sensor  880  at an image plane  870 . With the combination of the four lens elements, the aperture stop  800  and the IR-filter  860 , an image of the object to be photographed can be formed at the image sensor  880 . 
     
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 22 
               
             
             
               
                   
               
               
                 Optical data of this preferred embodiment 
               
               
                 f = 3.42 mm, Fno = 2.85, HFOV = 33.3 deg. 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Lens 1 
                 1.357900 (ASP) 
                 0.542 
                 Plastic 
                 1.544 
                 55.9 
                 2.63 
               
               
                 2 
                   
                 22.891300 (ASP)  
                 0.042 
               
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.016 
               
               
                 4 
                 Lens 2 
                 2.479490 (ASP) 
                 0.231 
                 Plastic 
                 1.650 
                 21.4 
                 −3.89 
               
               
                 5 
                   
                 1.205740 (ASP) 
                 0.545 
               
               
                 6 
                 Lens 3 
                 −2.761610 (ASP)  
                 0.546 
                 Plastic 
                 1.544 
                 55.9 
                 15.56 
               
               
                 7 
                   
                 −2.227420 (ASP)  
                 0.542 
               
               
                 8 
                 Lens 4 
                 1.134750 (ASP) 
                 0.600 
                 Plastic 
                 1.535 
                 56.3 
                 16.69 
               
               
                 9 
                   
                 1.060660 (ASP) 
                 0.700 
               
               
                 10 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.516 
                 64.1 
                 — 
               
               
                 11 
                   
                 Plano 
                 0.228 
               
               
                 12 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm. 
               
               
                 ASP stands for aspherical surfaces. 
               
             
          
         
       
     
     The optical data of this preferred embodiment are listed in Table 22, wherein the object-side surface and the image-side surface of the first lens element  810  to the fourth lens element  840  comply with the aspherical surface formula as given in Equation (15), and their aspheric coefficients are listed in Table 23 as follows: 
     
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 23 
               
               
                   
               
               
                 Aspheric coefficients of this preferred embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 1 
                 2 
                 4 
                 5 
               
               
                   
               
               
                 k = 
                 2.96124E−02 
                 −9.00000E+01 
                 −3.18530E+01 
                 1.18475E+00 
               
               
                 A4 = 
                 2.77385E−02 
                 5.31752E−02 
                 7.67451E−02 
                 −2.87424E−01 
               
               
                 A6 = 
                 5.02042E−02 
                 1.03699E−01 
                 −3.01960E−01 
                 2.32969E−01 
               
               
                 A8 = 
                 −2.93692E−02 
                 −1.92632E−01 
                 4.30269E−01 
                 −6.88366E−01 
               
               
                 A10 = 
                 1.01766E−01 
                 6.12670E−02 
                 −7.56449E−01 
                 4.39077E−01 
               
               
                 A12 = 
                   
                   
                   
                 −3.90517E−01 
               
               
                   
               
             
          
           
               
                   
                 Surface # 
               
             
          
           
               
                   
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 k = 
                 −2.21556E+00 
                 −2.51470E−02 
                 −3.49405E+00 
                 −3.25124E+00 
               
               
                 A4 = 
                 −2.26762E−01 
                 −4.06988E−01 
                 −2.47203E−01 
                 −1.65013E−01 
               
               
                 A6 = 
                 1.59884E−01 
                 4.55409E−01 
                 1.05586E−01 
                 7.15536E−02 
               
               
                 A8 = 
                 −3.38367E−01 
                 −4.62874E−01 
                 −2.10892E−02 
                 −2.58394E−02 
               
               
                 A10 = 
                 3.13744E−01 
                 1.90065E−01 
                 4.64582E−04 
                 6.26920E−03 
               
               
                 A12 = 
                 9.06079E−02 
                   
                 6.98447E−04 
                 −9.89401E−04 
               
               
                 A14 = 
                   
                   
                 −9.27712E−05 
                 8.08507E−05 
               
               
                   
               
             
          
         
       
     
     With reference to Table 22 and  FIG. 8B  for the optical lens for image pickup of this preferred embodiment, the focal length of the optical lens for image pickup is f=3.42 (mm), the overall aperture stop value (f-number) of the optical lens for image pickup is Fno=2.85, the half of maximum view angle is HFOV=33.3°. After the optical data of this preferred embodiment are calculated and derived, the optical lens satisfies related conditions as shown in Table 24 below, and the related symbols have been described above and thus will not be described again. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 24 
               
             
             
               
                   
               
               
                 Data of related relations of this preferred embodiment 
               
             
          
           
               
                   
                 Relation 
                 Data 
                 Relation 
                 Data 
               
               
                   
                   
               
             
          
           
               
                   
                 v 1  − v 2   
                 34.5 
                 (R 3  − R 4 )/(R 3  + R 4 ) 
                 0.35 
               
               
                   
                 (CT 2 /f) * 10 
                 0.68 
                 |(R 5  − R 6 )/(R 5  + R 6 )| 
                 0.11 
               
               
                   
                 T 12 /T 23   
                 0.11 
                 |(R 7  − R 8 )/(R 7  + R 8 )| 
                 0.03 
               
               
                   
                 T 23 /T 34   
                 1.00 
                 f/f 3   
                 0.22 
               
               
                   
                 R 1 /f 
                 0.40 
                 |f 2 |/f 3   
                 0.25 
               
               
                   
                 R 4 /f 
                 0.35 
                 TTL/ImgH 
                 1.86 
               
               
                   
                   
               
             
          
         
       
     
     According to the optical data as shown in Table 22 and the aberration curves as shown in  FIG. 8B , the optical lens for image pickup in accordance with this preferred embodiment of the present invention provides good correction results in aspects of the longitudinal spherical aberration, astigmatic field curving, and distortion. 
     In the optical lens for image pickup of the present invention, the lens element can be made of glass or plastic. If the lens element is made of glass, the selection of refractive power for the optical lens for image pickup can be more flexible. If the lens element is made of plastic, then the production cost can be reduced effectively. 
     In the optical lens for image pickup of the present invention, if the lens element has a convex surface, then the surface of the lens element is convex at a position near the optical axis; and if the lens element has a concave surface, then the surface of the lens element is concave at a position near the optical axis. 
     In the optical lens for image pickup of the present invention, at least one aperture stop (not as shown in figure) such as a glare stop or a field stop is provided for reducing stray lights to improve the image quality. 
     Tables 1 to 24 show changes of values of an optical lens for image pickup in accordance with different preferred embodiments of the present invention respectively, and even if different values are used, products of the same structure are intended to be covered by the scope of the present invention. It is noteworthy to point out that the aforementioned description and the illustration of related drawings are provided for the purpose of explaining the technical characteristics of the present invention, but not intended for limiting the scope of the present invention.