Abstract:
A photographing optical lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface, and a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface. At least one surface of the first lens element is aspheric and two surfaces of the second lens element are aspheric. The photographing optical lens assembly can also include a stop and an image plane. By adjusting the thicknesses of the first lens element and the second lens element as well as the allocation of the stop in the photographing optical lens assembly can effectively reduce the size as well as the sensitivity of the photographing optical lens assembly while gaining superior resolution.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 099144096 filed in Taiwan, R.O.C. on Dec. 15, 2010, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an optical lens assembly, and more particularly to a photographing optical lens assembly. 
     2. Related Art 
     In recent years, with the prosperity of photographing optical lens assemblies, the demand for compact photographing cameras boosts exponentially. The photo-sensing device, e.g. a sensor, of an ordinary photographing camera is commonly selected from a charge coupled device (CCD) and a complementary metal-oxide semiconductor (CMOS) device. In addition, as the advancing semiconductor manufacturing technology enables the minimization of the pixel size of sensors and the development of electronic products is heading toward full functionality and getting light, thin, short and small, the standards for the image quality of the photographing optical lens assemblies are rapidly raised. 
     In consideration of the aberration correction, the lens assembly of a conventional mobile electric device usually consists of three lens elements where the refractive power of the middle lens element is negative and those of the rest of the lens elements are positive. However, although the length of the lens assembly is reduced, the space of the photographing optical lens assembly available for forming image is also reduced. Additionally, the reduced space makes it difficult to incorporate the three lens elements into the photographing optical lens assembly. Therefore, the lens elements must become even thinner. However, when the lens element gets thinner, the uniformity of the lens thickness becomes worse, in terms of lens manufacturing by plastic injection molding. 
     A photographing optical lens assembly only with two lens elements is provided to effectively shorten the total length of the photographing optical lens assembly and improve the yield rate of the lens elements. For example, U.S. Pat. No. 7,525,741 discloses a two-piece optical lens system for taking image, comprising a first lens element with positive refractive power and a second lens element with negative refractive power in order from the object side to the image side. Although such arrangement enables the two-piece optical lens system to provide images having good resolution, it is difficult to shorten the total optical length of the two-piece optical lens system since the first lens element is a crescent lens having limited refractive power. Therefore, the inventors recognize that there is a need for a photographing optical lens which can be manufactured easily and has short optical length and low sensitivity. 
     SUMMARY 
     According to the present disclosure, a photographing optical lens assembly comprises, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface, and a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface. At least one of the object-side and the image-side surfaces of the first lens element are aspheric and the object-side and the image-side surfaces of the second lens element are aspheric. The photographing optical lens assembly further includes a stop and an image plane. 
     Near an optical axis, the thickness of the first lens element is CT 1  and the thickness of the second lens element is CT 2 . The axial distance between the first lens element and the second lens element is T 12 , the axial distance between the stop and the image plane is SL, the axial distance between the object-side surface of the first lens element and the image plane is TTL, the focal length of the photographing optical lens assembly is f, the Abbe number of the first lens element is V 1 , and the Abbe number of the second lens element is V 2 . The photographing optical lens assembly satisfies the following conditions:
 
0.25 &lt;CT   2   /T   12 &lt;0.80  (Condition 1):
 
0.30 &lt;CT   1   /f&lt; 0.57  (Condition 2):
 
20.0 &lt;V   1 - V   2 &lt;45.0  (Condition 3):
 
0.9 &lt;SL/TTL&lt; 1.2  (Condition 4):
 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the following detailed description when taken in connection with the accompanying drawings, which show, for the purpose of illustrations only, and thus do not limit other possible embodiments derived from the spirit of the present disclosure, and wherein: 
         FIG. 1A  is a schematic structural view of a first embodiment of a photographing optical lens assembly according to the present disclosure; 
         FIG. 1B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly in  FIG. 1A ; 
         FIG. 1C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 1A ; 
         FIG. 1D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 1A ; 
         FIG. 2A  is a schematic structural view of a second embodiment of a photographing optical lens assembly according to the present invention; 
         FIG. 2B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly in  FIG. 2A ; 
         FIG. 2C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in FIG.  2 A; 
         FIG. 2D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 2A ; 
         FIG. 3A  is a schematic structural view of a third embodiment of a photographing optical lens assembly according to the present disclosure; 
         FIG. 3B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly in  FIG. 3A ; 
         FIG. 3C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 3A ; 
         FIG. 3D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 3A ; 
         FIG. 4A  is a schematic structural view of a fourth embodiment of a photographing optical lens assembly according to the present disclosure; 
         FIG. 4B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly in  FIG. 4A ; 
         FIG. 4C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 4A ; and 
         FIG. 4D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly in  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION 
     One of the embodiments of the photographing optical lens assemblies of the present disclosure is described with  FIG. 1A  as an example, to illustrate the lens combinations, the configuration relationships and the conditions of the photographing optical lens assemblies that are commonly owned by the embodiments of the disclosure. The differences between the embodiments will be described in detail in embodiments other than the embodiment described in  FIG. 1 . 
     Taking  FIG. 1A  as an example, a photographing optical lens assembly  10 , from an object side to an image side along an optical axis (from left to right in  FIG. 1A ) in sequence, comprises an aperture stop  100 , a first lens element  110 , a second lens element  120 , an infrared filter  160 , and an image plane  170 . 
     By having positive refractive power, the first lens element  110  provides partial refractive power of the photographing optical lens assembly  10  for shortening the total optical length of the photographing optical lens assembly  10 . The first lens element  110  comprises an object-side surface  111  and an image-side surface  112 . At least one of the object-side surface  111  and the image-side surface  112  is aspheric. Moreover, the object-side surface  111  and the image-side surface  112  can be convex to enhance the positive refractive power of the first lens element  110 , thereby the total length of the photographing optical lens assembly  10  is shortened further. 
     The refractive power of the second lens element  120  is also positive, so that the overall positive refractive power of the photographing optical lens assembly is well distributed to the first lens element and the second lens element, and thereby, the sensitivity of the photographing optical lens assembly is reduced. The second lens element  120  comprises an object-side surface  121  and an image-side surface  122 . The object-side surface  121  and the image-side surface  122  can be aspheric. Moreover, when the object-side surface  121  is concave and the image-side surface  122  is convex, the astigmatism and the high-order aberration of the photographing optical lens assembly  10  are corrected. The term “total length” of the photographing optical lens assembly  10 ,” as used herein, refers to the axial distance between the object-side surface  111  of the first lens element  110  and the image plane  170 . 
     According to the present disclosure, the total length of the photographing optical lens assembly  10  is shortened since the refractive power of the first lens element  110  is positive and the aperture stop  100  is disposed between the object-side (the left side in  FIG. 1A ) and the first lens element  110 . 
     In addition, with the arrangement of the photographing optical lens assembly  10 , the exit pupil of the photographing optical lens assembly  10  gets away from the image plane  170 , such that when the incident light parallel to the optical axis arrives to the image plane, the incident angle of the incident light is approximately perpendicular to the image plane  170 . That is, the photographing optical lens assembly  10  has a telecentric feature in the image-side (the right side in  FIG. 1A ). Therefore, when an image sensor is disposed on the image plane  170 , the photo-sensing capability of the image sensor is improved due to the telecentric feature and the possibility of shading occurrences on the image generated by the image sensor is reduced. 
     Moreover, when the first lens element  110  and the second lens element  120  is made of plastic, the manufacturing cost and the weight of the photographing optical lens assembly  10  are reduced, and it is beneficial to manufacture aspherical lens elements. 
     The optical imaging system  10  of the present disclosure satisfies the following conditions:
 
0.25 &lt;CT   2   /T   12 &lt;0.80  (Condition 1):
 
0.30 &lt;CT   1   /f&lt; 0.57  (Condition 2):
 
20.0 &lt;V   1 -V 2 &lt;45.0  (Condition 3):
 
0.9 &lt;SL/TTL&lt; 1.2  (Condition 4):
 
     Near the optical axis, CT 1  is the thickness of the first lens element  110 , i.e. the axial distance between the object-side surface  111  and the image-side surface  112 , CT 2  is the thickness of the second lens element  120 , i.e. the axial distance between the object-side surface  121  and the image-side surface  122 . T 12  is the axial distance between the first lens element  110  and the second lens element  120 , i.e. the axial distance between the image-side surface  112  and the object-side surface  121 , f is the focal length of the photographing optical lens assembly  10 , V 1  is the Abbe number of the first lens element  110 , and V 2  is the Abbe number of the second lens element  120 , SL is the axial distance between the aperture stop  100  and the image plane  170 , TTL is the axial distance between the object-side surface  111  and the image plane  170 . 
     In the photographing optical lens assembly  10 , the positive refractive power of the first lens element  110  provides partial refractive power for shortening the total optical length of the photographing optical lens assembly  10 . When the second lens element  120  has positive refractive power, the overall positive refractive power of the photographing optical lens assembly  10  is well distributed to the first lens element  110  and the second lens element  120 , so that the sensitivity of the photographing optical lens assembly  10  is reduced. Furthermore, the positive refractive power of the first lens element  110  is increased and the total optical length of the photographing optical lens assembly  10  is further shortened when both the object-side surface  111  and the image-side surface  112  of the first lens element  110  are convex. The astigmatism and the high-order aberration of the photographing optical lens assembly  10  are corrected when the object-side surface  121  and the image-side surface  122  of the second lens element  120  are concave and convex, respectively. 
     When the photographing optical lens assembly  10  satisfies Condition 1, the thickness of the second lens element as well as the axial distance between the first lens element and the second lens element are proper, thereby an optimal balance between reducing the volume and improving the image quality of the photographing optical lens assembly is achieved. Preferably, the photographing optical lens assembly  10  satisfies 0.45&lt;CT 2 /T 12 &lt;0.65. When the photographing optical lens assembly  10  satisfies Condition 2, the first lens element has a proper thickness to overcome the difficulties in manufacturing and a higher yield rate of the lens elements is achieved. 
     When the photographing optical lens assembly  10  satisfies Condition 3, the chromatic aberration of the photographing optical lens assembly  10  is corrected. Preferably, the photographing optical lens assembly  10  satisfies 30.0&lt;V 1 -V 2 &lt;42.0. When the photographing optical lens assembly  10  satisfies Condition 4, a good balance between pursuing the telecentric feature and a wide field of view of the photographing optical lens assembly is achieved. 
     In the photographing optical lens assembly  10  according to the present disclosure, preferably, the object-side surface  111  has at least one inflection point, such as the first inflection point  113 , and the image-side surface  122  has at least one inflection point, such as the second inflection point  123 , so that the incident angle of the off-axis light projecting onto the image plane  170  is reduced to further correct the off-axis aberrations. 
     Besides, the photographing optical lens assembly  10  according to the present disclosure further comprises an image sensor  172  on the image plane  170 , and satisfies at least one of the following conditions:
 
−0.4 &lt;R   2   /R   1 &lt;0.0  (Condition 5):
 
0.05&lt;( R   4   −R   3 )/( R   4   +R   3 )&lt;0.19  (Condition 6):
 
0 &lt;f/f   2 &lt;0.6  (Condition 7):
 
0.15 millimeter (mm)&lt; CT   2 &lt;0.35 mm  (Condition 8):
 
0.6&lt;( SAG   22 )/ Y   22 &lt;0.7  (Condition 9):
 
 TTL/ImgH&lt; 2.40  (Condition 10):
 
     Wherein R 1  is the curvature radius of the object-side surface  111 , R 2  is the curvature radius of the image-side surface  112 , R 3  is the curvature radius of the object-side surface  121 , R 4  is the curvature radius of the image-side surface  122 , and f 2  is the focal length of the second lens element  120 , Y 22  is the largest vertical distance from a position where the off-axis light passing through the image-side surface  122  to the optical axis, and SAG 22  is a horizontal distance between a position on the image-side surface  112  of the second lens element  122  Y 22  away from the optical axis and a plane in tangency with the image-side surface of the second lens element  120  on the optical axis. ImgH is a half of the length of the diagonal line of an effective photosensitive area of the image sensor. 
     When the photographing optical lens assembly  10  of the present disclosure satisfies Condition 5, the spherical aberration of the photographing optical lens assembly  10  is corrected. When the photographing optical lens assembly  10  satisfies Condition 6, the astigmatism and the high-order aberration is corrected. When the photographing optical lens assembly  10  satisfies Condition 7, the refractive power of the second lens element  120  is proper, so that the overall positive refractive power of the photographing optical lens assembly  10  is well distributed to the first lens element  110  and the second lens element  120 , thereby the sensitivity of the photographing optical lens assembly  10  is reduced. When the photographing optical lens assembly  10  satisfies Condition 8, the thickness of the second lens element  120  is favorable for assembling the photographing optical lens assembly  10 . 
     When the photographing optical lens assembly  10  according to the present disclosure satisfies Condition 9, the curvature of the second lens element  120  is favorable for manufacturing the second lens element  120  and reducing the size of the photographing optical lens assembly  10 . Satisfaction of Condition 10 is favorable for reducing the size of the photographing optical lens assembly  10 , so that the photographing optical lens assembly  10  is suitable for being assembled in a compact and movable electric device. 
     In the photographing optical lens assembly  10  of the present disclosure, all lenses may be made of glass or plastic. If a lens is made of glass, there is more freedom in distributing the refractive power. If a lens is made of plastic, the production cost is effectively reduced. In addition, the surfaces of the lens can be aspheric and easily made into aspherical profiles, allowing more design parameter freedom which can reduce aberrations and total number of the lens elements required within a lens assembly in order to produce high quality images, so that the total track length of the assembly can be reduced effectively. 
     In the photographing optical lens assembly  10  of the present disclosure, a convex surface of a lens means the surface of the lens is convex at a paraxial site. A concave surface of a lens means the surface of the lens is concave at a paraxial site. In addition, at least one stop may be disposed within the photographing optical lens assembly  10  to reduce the occurrence of unwanted rays (such as flare stops), to adjust the field of view (such as field stops), or for other means to improve the image quality. 
     As for the photographing optical lens assembly  10  of the present disclosure, the specific schemes are further described with the following embodiments. Parameters in the embodiments are defined as follows: Fno is the f-number of the photographing optical lens assembly, and HFOV is a half of the maximal viewing angle in the photographing optical lens assembly. The aspheric surface in the embodiments may be represented by, but not limited to, the following aspheric surface equation (Formula ASP): 
     
       
         
           
             
               X 
               ⁡ 
               
                 ( 
                 Y 
                 ) 
               
             
             = 
             
               
                 
                   ( 
                   
                     
                       Y 
                       2 
                     
                     / 
                     R 
                   
                   ) 
                 
                 / 
                 
                   ( 
                   
                     1 
                     + 
                     
                       sqrt 
                       ⁡ 
                       
                         ( 
                         
                           1 
                           - 
                           
                             
                               ( 
                               
                                 1 
                                 + 
                                 k 
                               
                               ) 
                             
                             * 
                             
                               
                                 ( 
                                 
                                   Y 
                                   / 
                                   R 
                                 
                                 ) 
                               
                               2 
                             
                           
                         
                         ) 
                       
                     
                   
                   ) 
                 
               
               + 
               
                 
                   ∑ 
                   i 
                 
                 ⁢ 
                 
                   
                     ( 
                     Ai 
                     ) 
                   
                   * 
                   
                     ( 
                     
                       Y 
                       i 
                     
                     ) 
                   
                 
               
             
           
         
       
     
     Wherein Y is the distance from the point on the curve of the aspheric surface to the optical axis, X is the height of a point on the aspheric surface at a distance Y from the optical axis relative to the tangential plane at the aspheric surface vertex, k is a conic factor, Ai is an i th  order aspheric surface coefficient, and in the embodiments, i may be, but is not limited to, 4, 6, 8, 10, 12, 14 and 16. 
     The First Embodiment(Embodiment 1) 
       FIG. 1A  is a schematic structural view of a first embodiment of a photographing optical lens assembly according to the present disclosure. As shown in  FIG. 1A , the photographing optical lens assembly  10  comprises, in order from the object side to the image side (from left to right in  FIG. 1A ), the aperture stop  100 , the first lens element  110 , the second lens element  120 , the infrared filter  160 , and the image plane  170 . 
     In this embodiment, the wavelength of the light received by the photographing optical lens assembly  10  is, for example, but not limited to 587.6 nm. In some embodiments, the wavelength of the light received by the photographing optical lens assembly  10  may be adjusted according to actual requirements. 
     Furthermore, the first lens element  110  and the second lens element  120  are aspheric, and the aspheric surfaces of the present disclosure may satisfy Condition ASP, but are not limited thereto. As for the parameters of the aspheric surfaces, reference is made to Table 1-1 below. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1-1 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                 Sur- 
                   
                   
                   
                   
               
               
                 face# 
                 2 
                 3 
                 4 
                 5 
               
               
                   
               
             
          
           
               
                 k 
                 −2.00000E+02 
                 −7.93744E−01 
                 −2.67532E+00 
                 −1.51163E+00 
               
               
                 A 4   
                 9.30168E−01 
                 −2.10915E−01 
                 −9.30045E+00 
                 −1.15566E+00 
               
               
                 A 6   
                 −1.53228E+01 
                 −2.22205E+00 
                 4.04906E+01 
                 −9.89879E−01 
               
               
                 A 8   
                 9.36611E+01 
                 5.64719E−01 
                 −7.66919E+01 
                 1.04549E+01 
               
               
                 A 10   
                 −3.13342E+02 
                 4.73052E+01 
                 2.28284E+02 
                 3.68166E+01 
               
               
                 A 12   
                 −3.34277E+02 
                 −2.16834E+02 
                 −8.49678E+02 
                 −1.57796E+02 
               
               
                 A 14   
                 3.54106E+01 
                 3.22517E+02 
                 1.13088E+03 
                 1.58002E+02 
               
               
                 A 16   
                 2.19413E+03 
                 −1.52754E+02 
                 — 
                 −2.87437E+01 
               
               
                   
               
             
          
         
       
     
     The object-side surface  111  has at least one inflection point, such as the first inflection point  113 , and the image-side surface  122  also has one inflection point, such as the second inflection point  123 , so that the incident angle of the off-axis light projecting onto the image plane  170  is reduced to further correct the off-axis aberrations. 
     As for the parameters of the aspheric surfaces, reference is made to Table 1-2 below. 
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1-2 
               
             
             
               
                   
               
               
                 Embodiment 1 
               
               
                 f = 1.53 mm, Fno = 2.54, HFOV = 32.5 deg. 
               
             
          
           
               
                 Surface # 
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 0.016 
               
               
                 2 
                 Lens 1 
                  2.33963(ASP) 
                 0.793 
                 Plastic 
                 1.544 
                 55.9 
                 1.10 
               
               
                 3 
                   
                 −0.71201(ASP) 
                 0.501 
               
               
                 4 
                 Lens 2 
                 −0.29402(ASP) 
                 0.300 
                 Plastic 
                 1.632 
                 23.4 
                 54.44 
               
               
                 5 
                   
                 −0.40672(ASP) 
                 0.100 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.400 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 7 
                   
                 Plano 
                 0.302 
               
               
                 8 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is d-line 587.6 nm 
               
             
          
         
       
     
     The content of Table 1-3 may be deduced from Table 1-2. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 1-3 
               
               
                   
               
               
                 Embodiment 1 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 f (mm) 
                 1.53 
               
               
                   
                 Fno 
                 2.45 
               
               
                   
                 HFOV(deg.) 
                 32.5 
               
               
                   
                 V 1 -V 2   
                 32.50 
               
               
                   
                 CT 1 /f 
                 0.52 
               
               
                   
                 CT 2 /T 12   
                 0.60 
               
               
                   
                 CT 2  (mm) 
                 0.300 
               
               
                   
                 R 2 /R 1   
                 −0.30 
               
               
                   
                 (R 4  − R 3 )/(R 4   + R 3 ) 
                 0.16 
               
               
                   
                 f/f 2   
                 0.03 
               
               
                   
                 (SAG 22 )/Y 22   
                 0.64 
               
               
                   
                 SL/TTL 
                 1.01 
               
               
                   
                 TTL/ImgH 
                 2.26 
               
               
                   
               
             
          
         
       
     
     In this embodiment of the photographing optical lens assembly  10 , the optimal balance between reducing the volume and improving the image quality of the photographing optical lens assembly is achieved since CT 2 /T 12  equals 0.60, satisfying Condition 1. The difficulty to manufacture the first lens element  110  is lowered and the yield rate of the first lens element  110  is raised since CT 1 /f equals 0.52, satisfying Condition 2. The chromatic aberration of the photographing optical lens assembly is corrected since V 1 -V 2  equals 32.5, satisfying Condition 3. A good balance between pursuing the telecentric feature and a wide field of view of the photographing optical lens assembly is achieved since SL/TTL equals 1.01, satisfying Condition 4. 
     The spherical aberration of the photographing optical lens assembly  10  is corrected since R 2 /R 1  equals −0.30, satisfying Condition 5. The astigmatism and the high-order aberration of the photographing optical lens assembly  10  are corrected since (R 4 −R 3 )/(R 4 +R 3 ) equals 0.16, satisfying Condition 6. Since f/f 2  equals 0.03, satisfying Condition 7, the overall positive refractive power of the photographing optical lens assembly  10  is well distributed to the first lens element  110  and the second lens element  120  so that the sensitivity of the photographing optical lens assembly  10  is lowered. 
     The photographing optical lens assembly  10  may be assembled easily since CT 2  equals 0.300 mm, satisfying Condition 8. The curvature of the second lens element  120  is proper and favorable for manufacturing of the second lens element  120  and for reducing the size of the photographing optical lens assembly  10  since (SAG 22 )/Y 22  equals 0.64, satisfying Condition 9. Since TTL/ImgH equals 2.26, satisfying Condition 10, the size of the photographing optical lens assembly  10  is reduced so that the photographing optical lens assembly  10  is suitable for being assembled in a compact and movable electric device. 
       FIG. 1B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly in  FIG. 1A . The longitudinal spherical aberration curves of the lights having the wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm in the photographing optical lens assembly  10  are respectively indicated by a solid line L, a dashed line M, and a dotted line N in  FIG. 1B . Horizontal axis is the focus position (millimeter, mm), and vertical axis is the normalized entrance pupil or the aperture value. In other words, after the light enters the photographing optical lens assembly  10 , the differences between the focus positions of the paraxial light (the longitudinal coordinate is close to 0) and the fringe light (the longitudinal coordinate is close to 1) can be observed from the longitudinal spherical aberration curves. It can be observed from  FIG. 1B  that, no matter the wavelength of the light received by the photographing optical lens assembly  10  of this embodiment is 486.1 nm, 587.6 nm, or 656.3 nm, the longitudinal spherical aberration generated by the photographing optical lens assembly  10  is within the range of −0.05 mm to 0.02 mm. 
     In the second embodiment to the fourth embodiment and the schematic views of the longitudinal spherical aberration curves in  FIGS. 2B ,  3 B, and  4 B, the solid line L, the dashed line M, and the dotted line N respectively indicate the longitudinal spherical aberration curves of the lights having the wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm, which will not be repeated herein for the sake of conciseness. 
       FIG. 1C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  10  in  FIG. 1A . The astigmatic field curve of a tangential plane is a dashed line T in  FIG. 1C . The astigmatic field curve of a sagittal plane is a solid line S in  FIG. 1C . Horizontal axis is the focus position (mm), and vertical axis is image height (mm). The differences in focus position due to different curvatures of the tangential plane and the sagittal plane can be observed from the astigmatic field curves. It can be observed from  FIG. 1C  that, the astigmatic field curvature of the tangential plane generated when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  10  is within a range of −0.100 mm to 0.025 mm, and the astigmatic field curvature of the sagittal plane is within a range of −0.100 mm to 0.0 mm. 
     In the second embodiment to the fourth embodiment and the schematic views of the astigmatic field curves in  FIGS. 2C ,  3 C, and  4 C, the solid line S indicates the astigmatic field curve of the sagittal plane, and the dashed line T indicates the astigmatic field curve of the tangential plane, which will not be repeated herein for the sake of conciseness. 
       FIG. 1D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  10  in  FIG. 1A . Horizontal axis is distortion ratio (%), and vertical axis is image height (mm). In other words, the differences in distortion ratio caused by different image heights can be seen from the distortion curve G. It can be observed from  FIG. 1D  that, the distortion ratio generated when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  10  is within a range of 0% to 2.25%. As shown in  FIGS. 1B to 1D , the photographing optical lens assembly  10 , designed according to the first embodiment, is capable of effectively correcting various aberrations. 
     In the second embodiment to the fourth embodiment and the schematic views of the distortion curves in  FIGS. 2D ,  3 D, and  4 D, the solid line G indicates the distortion curve of the light having the wavelength of 587.6 nm, which will not be repeated herein for the sake of conciseness. 
     It should be noted that, the distortion curves and the astigmatic field curves of the light having wavelengths of 486.1 nm and 656.3 nm in the photographing optical lens assembly  10  are close to the distortion curve and the astigmatic field curve of the wavelength of 587.6 nm. In order to prevent the possible visual confusion about  FIGS. 1C and 1D , the distortion curve and the astigmatic field curves of the light wavelengths of 486.1 nm and 656.3 nm are not shown in  FIGS. 1C and 1D , and the same applies throughout the second embodiment to the fourth embodiment. 
     The Second Embodiment(Embodiment 2) 
       FIG. 2A  is a schematic structural view of a second embodiment of a photographing optical lens assembly according to the present disclosure. The specific implementation is substantially the same as that in the first embodiment, and the elements in the second embodiment are the same as those in the first embodiment, so that the element symbols all begin with “2” as the hundredth digit, which represents that the elements have the same function or structure. For the sake of conciseness, only the differences are illustrated below, and the similar parts will not be repeated herein. 
     In this embodiment, for example, the wavelength of the light received by the photographing optical lens assembly  20  is 587.6 nm, but the wavelength of the light received by the photographing optical lens assembly  20  may be adjusted according to actual requirements, and is not limited to the wavelength value mentioned above. 
     Furthermore, a first lens element  210  and a second lens element  220  are aspheric, and the aspheric surfaces, for example, satisfy the Condition ASP, but are not limited thereto. As for the parameters of the aspheric surfaces, reference is made to Table 2-1 below. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2-1 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                 Sur- 
                   
                   
                   
                   
               
               
                 face# 
                 2 
                 3 
                 4 
                 5 
               
               
                   
               
             
          
           
               
                 k 
                 −2.00000E+02 
                 −4.70620E−01 
                 −1.98272E+00 
                 −9.84239E−01 
               
               
                 A 4   
                 −3.92224E−01 
                 −2.78636E−01 
                 −8.01298E+00 
                 −1.31648E+00 
               
               
                 A 6   
                 −2.08511E+00 
                 −1.09906E+00 
                 3.49250E+01 
                 1.75410E+00 
               
               
                 A 8   
                 −2.39756E+00 
                 −5.50572E+00 
                 −6.83052E+01 
                 6.89798E+00 
               
               
                 A 10   
                 −7.29603E+01 
                 6.06858E+01 
                 2.29668E+02 
                 3.36723E+01 
               
               
                 A 12   
                 −3.34277E+02 
                 −2.26641E+02 
                 −8.07920E+02 
                 −1.54059E+02 
               
               
                 A 14   
                 3.54109E+01 
                 2.95757E+02 
                 9.95366E+02 
                 1.79213E+02 
               
               
                 A 16   
                 2.19413E+03 
                 −1.59284E+02 
                 — 
                 −5.80932E+01 
               
               
                   
               
             
          
         
       
     
     In this embodiment, the first lens element  210  has positive refractive power, and the second lens element  220  also has positive refractive power. The object-side surface  211  and the image-side surface  212  are convex and the object-side surface  221  is concave, and the image-side surface  222  is convex. The object-side surface  211  has at least one inflection point, such as a first inflection point  213 , and the image-side surface  222  also has one inflection point, such as a second inflection point  223 , so that the incident angle of the off-axis light projecting onto an image plane  270  is reduced to further correct the off-axis aberrations. 
     The detailed data of the photographing optical lens assembly  20  is as shown in Table 2-2 below. 
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2-2 
               
             
             
               
                   
               
               
                 Embodiment 2 
               
               
                 f = 1.55 mm, Fno = 2.45, HFOV = 32.3 deg. 
               
             
          
           
               
                 Surface # 
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 0.070 
               
               
                 2 
                 Lens 1 
                  3.94940(ASP) 
                 0.690 
                 Plastic 
                 1.544 
                 55.9 
                 1.18 
               
               
                 3 
                   
                 −0.72037(ASP) 
                 0.620 
               
               
                 4 
                 Lens 2 
                 −0.34214(ASP) 
                 0.300 
                 Plastic 
                 1.583 
                 30.2 
                 49.85 
               
               
                 5 
                   
                 −0.44741(ASP) 
                 0.100 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.400 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 7 
                   
                 Plano 
                 0.234 
               
               
                 8 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is d-line 587.6 nm 
               
             
          
         
       
     
     The content of Table 2-3 may be deduced from Table 2-2. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 2-3 
               
               
                   
               
               
                 Embodiment 2 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 f (mm) 
                 1.55 
               
               
                   
                 Fno 
                 2.45 
               
               
                   
                 HFOV(deg.) 
                 32.3 
               
               
                   
                 V 1 -V 2   
                 25.70 
               
               
                   
                 CT 1 /f 
                 0.45 
               
               
                   
                 CT 2 /T 12   
                 0.48 
               
               
                   
                 CT 2  (mm) 
                 0.300 
               
               
                   
                 R 2 /R 1   
                 −0.18 
               
               
                   
                 (R 4  − R 3 )/(R 4  + R 3 ) 
                 0.13 
               
               
                   
                 f/f 2   
                 0.03 
               
               
                   
                 (SAG 22 )/Y 22   
                 0.63 
               
               
                   
                 SL/TTL 
                 1.03 
               
               
                   
                 TTL/ImgH 
                 2.21 
               
               
                   
               
             
          
         
       
     
       FIG. 2B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly  20  in  FIG. 2A . It can be observed from  FIG. 2B  that no matter the wavelength of the light received by the photographing optical lens assembly  20  of this embodiment is 486.1 nm, 587.6 nm, or 656.3 nm, the longitudinal spherical aberration generated by the photographing optical lens assembly  20  is within the range of −0.025 mm to 0.025 mm. 
       FIG. 2C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  20  in  FIG. 2A . It can be observed from  FIG. 2C  that, when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  20 , the astigmatic field curvature of the tangential plane is within a range of −0.05 mm to 0.05 mm, and the astigmatic field curvature of the sagittal plane is within a range of −0.05 mm to 0.025 mm. 
       FIG. 2D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  20  in  FIG. 2A . It can be observed from  FIG. 2D  that, the distortion ratio generated when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  20  is within a range of 0.0% to 2.5%. As shown in  FIGS. 2B to 2D , the photographing optical lens assembly  20 , designed according to the second embodiment, is capable of effectively correcting various aberrations. 
     The Third Embodiment (Embodiment 3) 
       FIG. 3A  is a schematic structural view of a third embodiment of a photographing optical lens assembly according to the present disclosure. The specific implementation is substantially the same as that in the first embodiment, and the elements in the third embodiment are the same as those in the first embodiment, so that the element symbols all begin with “3” as the hundredth digit, which represents that the elements have the same function or structure. For the sake of conciseness, only the differences are illustrated below, and the similar parts will not be repeated herein. 
     In this embodiment, for example, the wavelength of the light received by the photographing optical lens assembly  30  is 587.6 nm, but the wavelength of the light received by the photographing optical lens assembly  30  may be adjusted according to actual requirements, and is not limited to the wavelength value mentioned above. 
     Furthermore, a first lens element  310  and a second lens element  320  are aspheric, and the aspheric surfaces, for example, satisfy the Condition ASP, but are not limited thereto. As for the parameters of the aspheric surfaces, reference is made to Table 3-1 below. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3-1 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                 Sur- 
                   
                   
                   
                   
               
               
                 face# 
                 2 
                 3 
                 4 
                 5 
               
               
                   
               
             
          
           
               
                 k 
                 −4.68411E+01 
                 −4.35388E−01 
                 −2.64224E+00 
                 −1.50101E+00 
               
               
                 A 4   
                 −1.67478E+00 
                 −2.54184E−01 
                 −8.09202E+00 
                 −8.53226E−01 
               
               
                 A 6   
                 1.03987E+01 
                 −1.00669E+00 
                 3.97972E+01 
                 −2.12583E+00 
               
               
                 A 8   
                 −2.05415E+02 
                 −7.54356E+00 
                 −9.55881E+01 
                 8.37572E+00 
               
               
                 A 10   
                 6.86656E+02 
                 7.61057E+01 
                 2.64102E+02 
                 3.82907E+01 
               
               
                 A 12   
                 −3.50363E+02 
                 −3.40556E+02 
                 −7.35563E+02 
                 −1.47398E+02 
               
               
                 A 14   
                 2.25433E+01 
                 2.90194E+02 
                 8.61004E+02 
                 1.69378E+02 
               
               
                 A 16   
                 2.20599E+03 
                 −2.27770E+02 
                 — 
                 −6.42944E+01 
               
               
                   
               
             
          
         
       
     
     In this embodiment, the first lens element  310  has positive refractive power, and the second lens element  320  also has positive refractive power. The object-side surface  311  and the image-side surface  312  are convex and the object-side surface  321  is concave, and the image-side surface  322  is convex. The object-side surface  311  has at least one inflection point, such as a first inflection point  313 , and the image-side surface  322  also has one inflection point, such as a second inflection point  323 , so that the incident angle of the off-axis light projecting onto an image plane  370  is reduced to further correct the off-axis aberrations. 
     The detailed data of the photographing optical lens assembly  30  is as shown in Table 3-2 below. 
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3-2 
               
             
             
               
                   
               
               
                 Embodiment 3 
               
               
                 f = 1.36 mm, Fno = 2.70, HFOV = 35.8 deg. 
               
             
          
           
               
                 Surface # 
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 0.081 
               
               
                 2 
                 Lens 1 
                 10.53940(ASP) 
                 0.583 
                 Plastic 
                 1.514 
                 56.8 
                 1.03 
               
               
                 3 
                   
                 −0.54919(ASP) 
                 0.550 
               
               
                 4 
                 Lens 2 
                 −0.35283(ASP) 
                 0.413 
                 Plastic 
                 1.634 
                 23.8 
                 4.12 
               
               
                 5 
                   
                 −0.45196(ASP) 
                 0.100 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.400 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 7 
                   
                 Plano 
                 0.196 
               
               
                 8 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is d-line 587.6 nm 
               
             
          
         
       
     
     The content of Table 3-3 may be deduced from Table 3-2. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 3-3 
               
               
                   
               
               
                 Embodiment 3 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 f (mm) 
                 1.36 
               
               
                   
                 Fno 
                 2.70 
               
               
                   
                 HFOV(deg.) 
                 35.8 
               
               
                   
                 V 1 -V 2   
                 33.00 
               
               
                   
                 CT 1 /f 
                 0.43 
               
               
                   
                 CT 2 /T 12   
                 0.75 
               
               
                   
                 CT 2  (mm) 
                 0.413 
               
               
                   
                 R 2 /R 1   
                 −0.05 
               
               
                   
                 (R 4  − R 3 )/(R 4   + R 3 ) 
                 0.12 
               
               
                   
                 f/f 2   
                 0.33 
               
               
                   
                 (SAG 22 /Y 22   
                 0.63 
               
               
                   
                 SL/TTL 
                 1.04 
               
               
                   
                 TTL/ImgH 
                 2.11 
               
               
                   
               
             
          
         
       
     
       FIG. 3B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly  30  in  FIG. 3A . It can be observed from  FIG. 3B  that no matter the wavelength of the light received by the photographing optical lens assembly  30  of this embodiment is 486.1 nm, 587.6 nm, or 656.3 nm, the longitudinal spherical aberration generated by the photographing optical lens assembly  30  is within the range of −0.025 mm to 0.025 mm. 
       FIG. 3C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  30  in  FIG. 3A . It can be observed from  FIG. 3C  that, when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  30 , the astigmatic field curvature of the tangential plane is within a range of −0.050 mm to 0.050 mm, and the astigmatic field curvature of the sagittal plane is within a range of −0.050 mm to 0.025 mm. 
       FIG. 3D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  30  in  FIG. 3A . It can be observed from  FIG. 3D  that, the distortion ratio generated when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  30  is within a range of 0.0% to 2.0%. As shown in  FIGS. 3B to 3D , the photographing optical lens assembly  30 , designed according to the third embodiment, is capable of effectively correcting various aberrations. 
     The Fourth Embodiment (Embodiment 4) 
       FIG. 4A  is a schematic structural view of a fourth embodiment of a photographing optical lens assembly according to the present disclosure. The specific implementation is substantially the same as that in the first embodiment, and the elements in the fourth embodiment are the same as those in the first embodiment, so that the element symbols all begin with “4” as the hundredth digit, which represents that the elements have the same function or structure. For the sake of conciseness, only the differences are illustrated below, and the similar parts will not be repeated herein. 
     In this embodiment, for example, the wavelength of the light received by the photographing optical lens assembly  40  is 587.6 nm, but the wavelength of the light received by the photographing optical lens assembly  40  may be adjusted according to actual requirements, and is not limited to the wavelength value mentioned above. 
     Furthermore, a first lens element  410  and a second lens element  420  are aspheric, and the aspheric surfaces, for example, satisfy the Condition ASP, but are not limited thereto. As for the parameters of the aspheric surfaces, reference is made to Table 4-1 below. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 4-1 
               
             
             
               
                   
               
               
                 Aspheric Coefficients 
               
             
          
           
               
                 Sur- 
                   
                   
                   
                   
               
               
                 face# 
                 2 
                 3 
                 4 
                 5 
               
               
                   
               
             
          
           
               
                 K 
                 −1.72465E+02 
                 −5.80032E−01 
                 −3.22677E+00 
                 −1.43718E+00 
               
               
                 A 4   
                 −6.06983E−01 
                 −2.88366E−01 
                 −8.95620E+00 
                 −9.49368E−01 
               
               
                 A 6   
                 −1.41354E−01 
                 −3.08513E−01 
                 3.89266E+01 
                 −2.04793E+00 
               
               
                 A 8   
                 −1.71250E+01 
                 −1.12634E+01 
                 −8.93962E+01 
                 9.70601E+00 
               
               
                 A 10   
                 −3.71417E+01 
                 7.92201E+01 
                 2.73913E+02 
                 3.82520E+01 
               
               
                 A 12   
                 −3.34277E+02 
                 −2.52061E+02 
                 −7.60622E+02 
                 −1.49921E+02 
               
               
                 A 14   
                 3.54110E+01 
                 2.95478E+02 
                 8.16661E+02 
                 1.61386E+02 
               
               
                 A 16   
                 2.19413E+03 
                 −1.53049E+02 
                 — 
                 −5.23611E+01 
               
               
                   
               
             
          
         
       
     
     In this embodiment, the first lens element  410  has positive refractive power, and the second lens element  420  has positive refractive power. The object-side surface  411  and the image-side surface  412  are convex and the object-side surface  421  is concave, and the image-side surface  422  is convex. The object-side surface  411  has at least one inflection point, such as a first inflection point  413 , and the image-side surface  422  also has one inflection point, such as a second inflection point  423 , so that the incident angle of the off-axis light projecting onto an image plane  470  is reduced to further correct the off-axis aberrations. 
     The detailed data of the photographing optical lens assembly  40  is as shown in Table 4-2 below. 
     
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4-2 
               
             
             
               
                   
               
               
                 Embodiment 4 
               
               
                 f = 1.50 mm, Fno = 2.45, HFOV = 33.2 deg. 
               
             
          
           
               
                 Surface # 
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal length 
               
               
                   
               
             
          
           
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 0.075 
               
               
                 2 
                 Lens 1 
                  4.29580(ASP) 
                 0.692 
                 Plastic 
                 1.530 
                 55.8 
                 1.16 
               
               
                 3 
                   
                 −0.68025(ASP) 
                 0.620 
               
               
                 4 
                 Lens 2 
                 −0.33583(ASP) 
                 0.323 
                 Plastic 
                 1.614 
                 25.6 
                 7.80 
               
               
                 5 
                   
                 −0.42867(ASP) 
                 0.100 
               
               
                 6 
                 IR-filter 
                 Plano 
                 0.400 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 7 
                   
                 Plano 
                 0.213 
               
               
                 8t 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is d-line 587.6 nm 
               
             
          
         
       
     
     The content of Table 4-3 may be deduced from Table 4-2. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 4-3 
               
               
                   
               
               
                 Embodiment 4 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 f (mm) 
                 1.50 
               
               
                   
                 Fno 
                 2.45 
               
               
                   
                 HFOV(deg.) 
                 33.2 
               
               
                   
                 V 1 -V 2   
                 30.20 
               
               
                   
                 CT 1 /f 
                 0.46 
               
               
                   
                 CT 2 /T 12   
                 0.52 
               
               
                   
                 CT 2  (mm) 
                 0.323 
               
               
                   
                 R 2 /R 1   
                 −0.16 
               
               
                   
                 (R 4  − R 3 )/(R 4  + R 3 ) 
                 0.12 
               
               
                   
                 f/f 2   
                 0.19 
               
               
                   
                 (SAG 22 )/Y 22   
                 0.65 
               
               
                   
                 SL/TTL 
                 1.03 
               
               
                   
                 TTL/ImgH 
                 2.21 
               
               
                   
               
             
          
         
       
     
       FIG. 4B  is a schematic view of longitudinal spherical aberration curves when the lights having wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are respectively projected in the photographing optical lens assembly  40  in  FIG. 4A . It can be observed from  FIG. 4B  that, no matter the wavelength of the light received by the photographing optical lens assembly  40  of this embodiment is 486.1 nm, 587.6 nm, or 656.3 nm, the longitudinal spherical aberration generated by the photographing optical lens assembly  40  is within the range of −0.050 mm to 0.025 mm. 
       FIG. 4C  is a schematic view of astigmatic field curves when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  40  in  FIG. 4A . It can be observed from  FIG. 4C  that, when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  40 , the astigmatic field curvature of the tangential plane generated is within a range of −0.050 mm to 0.025 mm, and the astigmatic field curvature of the sagittal plane is within a range of −0.050 mm to 0.0 mm. 
       FIG. 4D  is a schematic view of a distortion curve when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  40  in  FIG. 4A . It can be observed from  FIG. 4D  that, the distortion ratio generated when the light having the wavelength of 587.6 nm is projected in the photographing optical lens assembly  40  is within a range of 0.0% to 2.5%. As shown in  FIGS. 4B to 4D , the photographing optical lens assembly  40 , designed according to the fourth embodiment, is capable of effectively correcting various aberrations.