Patent Publication Number: US-9413934-B2

Title: Optical imaging lens and electronic device comprising the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to Taiwan Application No. 103108738, filed on Mar. 12, 2014. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an optical imaging lens set and an electronic device which includes such optical imaging lens set. Specifically speaking, the present invention is directed to an optical imaging lens set of six lens elements and an electronic device which includes such optical imaging lens set of six lens elements. 
     2. Description of the Prior Art 
     In recent years, the popularity of mobile phones and digital cameras makes the sizes of various portable electronic products reduce quickly, and so does that of the photography modules. The current trend of research is to develop an optical imaging lens set of a shorter length with uncompromised good quality. The most important characters of an optical imaging lens set are image quality and size. 
     Therefore, how to reduce the total length of a photographic device, but still maintain good optical performance, is an important research objective. 
     SUMMARY OF THE INVENTION 
     In light of the above, the present invention proposes an optical imaging lens set that is lightweight, has a low production cost, has an enlarged half of field of view, has a high resolution and has high image quality. The optical imaging lens set of six lens elements of the present invention has a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element sequentially from an object side to an image side along an optical axis. 
     The present invention provides an optical imaging lens set, from an object side toward an image side in order along an optical axis comprising: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element, the first lens element has negative refractive power, the second lens element has negative refractive power, the third lens element has refractive power, the fourth lens element has an image-side surface with a convex part in a vicinity of the optical axis, the fifth lens element has an image-side surface with a convex part in a vicinity of the optical axis, the sixth lens element has an image-side surface with a concave part in a vicinity of its periphery, wherein the optical imaging lens set does not include any lens element with refractive power other than said first, second, third, fourth, fifth and sixth lens elements. 
     In the optical imaging lens set of six lens elements of the present invention, an air gap G 12  along the optical axis is disposed between the first lens element and the second lens element, an air gap G 23  along the optical axis is disposed between the second lens element and the third lens element, an air gap G 34  along the optical axis is disposed between the third lens element and the fourth lens element, an air gap G 45  along the optical axis is disposed between the fourth lens element and the fifth lens element, an air gap G 56  along the optical axis is disposed between the fifth lens element and the sixth lens element, and the sum of total five air gaps between adjacent lens elements from the first lens element to the sixth lens element along the optical axis is Gaa, Gaa=G 12 +G 23 +G 34 +G 45  +G 56 . 
     In the optical imaging lens set of six lens elements of the present invention, the first lens element has a first lens element thickness T 1  along the optical axis, the second lens element has a second lens element thickness T 2  along the optical axis, the third lens element has a third lens element thickness T 3  along the optical axis, the fourth lens element has a fourth lens element thickness T 4  along the optical axis, the fifth lens element has a fifth lens element thickness T 5  along the optical axis, the sixth lens element has a sixth lens element thickness T 6  along the optical axis, and the total thickness of all the lens elements in the optical imaging lens set along the optical axis is ALT, ALT=T 1 +T 2 +T 3 +T 4 +T 5 +T 6 . 
     Besides, the total length of the optical imaging lens set is TTL, the distance between the image-side surface of the sixth lens element to an image plane along the optical axis is BFL (back focal length). 
     In the optical imaging lens set of six lens elements of the present invention, the relationship (G 23 +G 34 )/(G 45 +G 56 )≧9.0 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship ALT/G 23 ≦6.0 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship 5.26≦ALT/T 5 ≦10.38 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship BFL/G 12 ≧0.85 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship BFL/G 23 ≦1.16 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship BFL/T 2 ≦4.34 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship 1.33≦BFL/T 5 ≦3.91 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship Gaa/G 12 ≧2.0 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship Gaa/G 23 ≦2.55 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship Gaa/G 34 ≧3.50 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship TTL/G 23 ≦10.0 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship TTL/T 1 ≦23.76 is satisfied. 
     In the optical imaging lens set of six lens elements of the present invention, the relationship TTL/T 2 ≦26.0 is satisfied. 
     The present invention also proposes an electronic device which includes the optical imaging lens set as described above. The electronic device includes a case and an image module disposed in the case. The image module includes an optical imaging lens set as described above, a barrel for the installation of the optical imaging lens set, a module housing unit for the installation of the barrel, a substrate for the installation of the module housing unit, and an image sensor disposed on the substrate and at an image side of the optical imaging lens set. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a first example of the optical imaging lens set of the present invention. 
         FIG. 2A  illustrates the longitudinal spherical aberration on the image plane of the first example. 
         FIG. 2B  illustrates the astigmatic aberration on the sagittal direction of the first example. 
         FIG. 2C  illustrates the astigmatic aberration on the tangential direction of the first example. 
         FIG. 2D  illustrates the distortion aberration of the first example. 
         FIG. 3  illustrates a second example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 4A  illustrates the longitudinal spherical aberration on the image plane of the second example. 
         FIG. 4B  illustrates the astigmatic aberration on the sagittal direction of the second example. 
         FIG. 4C  illustrates the astigmatic aberration on the tangential direction of the second example. 
         FIG. 4D  illustrates the distortion aberration of the second example. 
         FIG. 5  illustrates a third example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 6A  illustrates the longitudinal spherical aberration on the image plane of the third example. 
         FIG. 6B  illustrates the astigmatic aberration on the sagittal direction of the third example. 
         FIG. 6C  illustrates the astigmatic aberration on the tangential direction of the third example. 
         FIG. 6D  illustrates the distortion aberration of the third example. 
         FIG. 7  illustrates a fourth example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 8A  illustrates the longitudinal spherical aberration on the image plane of the fourth example. 
         FIG. 8B  illustrates the astigmatic aberration on the sagittal direction of the fourth example. 
         FIG. 8C  illustrates the astigmatic aberration on the tangential direction of the fourth example. 
         FIG. 8D  illustrates the distortion aberration of the fourth example. 
         FIG. 9  illustrates a fifth example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 10A  illustrates the longitudinal spherical aberration on the image plane of the fifth example. 
         FIG. 10B  illustrates the astigmatic aberration on the sagittal direction of the fifth example. 
         FIG. 10C  illustrates the astigmatic aberration on the tangential direction of the fifth example. 
         FIG. 10D  illustrates the distortion aberration of the fifth example. 
         FIG. 11  illustrates a sixth example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 12A  illustrates the longitudinal spherical aberration on the image plane of the sixth example. 
         FIG. 12B  illustrates the astigmatic aberration on the sagittal direction of the sixth example. 
         FIG. 12C  illustrates the astigmatic aberration on the tangential direction of the sixth example. 
         FIG. 12D  illustrates the distortion aberration of the sixth example. 
         FIG. 13  illustrates a seventh example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 14A  illustrates the longitudinal spherical aberration on the image plane of the seventh example. 
         FIG. 14B  illustrates the astigmatic aberration on the sagittal direction of the seventh example. 
         FIG. 14C  illustrates the astigmatic aberration on the tangential direction of the seventh example. 
         FIG. 14D  illustrates the distortion aberration of the seventh example. 
         FIG. 15  illustrates an eighth example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 16A  illustrates the longitudinal spherical aberration on the image plane of the eighth example. 
         FIG. 16B  illustrates the astigmatic aberration on the sagittal direction of the eighth example. 
         FIG. 16C  illustrates the astigmatic aberration on the tangential direction of the eighth example. 
         FIG. 16D  illustrates the distortion aberration of the eighth example. 
         FIG. 17  illustrates a ninth example of the optical imaging lens set of six lens elements of the present invention. 
         FIG. 18A  illustrates the longitudinal spherical aberration on the image plane of the ninth example. 
         FIG. 18B  illustrates the astigmatic aberration on the sagittal direction of the ninth example. 
         FIG. 18C  illustrates the astigmatic aberration on the tangential direction of the ninth example. 
         FIG. 18D  illustrates the distortion aberration of the ninth example. 
         FIG. 19  illustrates exemplificative shapes of the optical imaging lens element of the present invention. 
         FIG. 20  illustrates a first preferred example of the portable electronic device with an optical imaging lens set of the present invention. 
         FIG. 21  illustrates a second preferred example of the portable electronic device with an optical imaging lens set of the present invention. 
         FIG. 22  shows the optical data of the first example of the optical imaging lens set. 
         FIG. 23  shows the aspheric surface data of the first example. 
         FIG. 24  shows the optical data of the second example of the optical imaging lens set. 
         FIG. 25  shows the aspheric surface data of the second example. 
         FIG. 26  shows the optical data of the third example of the optical imaging lens set. 
         FIG. 27  shows the aspheric surface data of the third example. 
         FIG. 28  shows the optical data of the fourth example of the optical imaging lens set. 
         FIG. 29  shows the aspheric surface data of the fourth example. 
         FIG. 30  shows the optical data of the fifth example of the optical imaging lens set. 
         FIG. 31  shows the aspheric surface data of the fifth example. 
         FIG. 32  shows the optical data of the sixth example of the optical imaging lens set. 
         FIG. 33  shows the aspheric surface data of the sixth example. 
         FIG. 34  shows the optical data of the seventh example of the optical imaging lens set. 
         FIG. 35  shows the aspheric surface data of the seventh example. 
         FIG. 36  shows the optical data of the eighth example of the optical imaging lens set. 
         FIG. 37  shows the aspheric surface data of the eighth example. 
         FIG. 38  shows the optical data of the ninth example of the optical imaging lens set. 
         FIG. 39  shows the aspheric surface data of the ninth example. 
         FIG. 40  shows some important ratios in the examples. 
     
    
    
     DETAILED DESCRIPTION 
     Before the detailed description of the present invention, the first thing to be noticed is that in the present invention, similar (not necessarily identical) elements are labeled as the same numeral references. In the entire present specification, “a certain lens element has negative/positive refractive power” refers to the part in a vicinity of the optical axis of the lens element has negative/positive refractive power. “An object-side/image-side surface of a certain lens element has a concave/convex part” refers to the part is more concave/convex in a direction parallel with the optical axis to be compared with an outer region next to the region. Taking  FIG. 19  for example, the optical axis is “I” and the lens element is symmetrical with respect to the optical axis I. The object side of the lens element has a convex part in the region A, a concave part in the region B, and a convex part in the region C because region A is more convex in a direction parallel with the optical axis than an outer region (region B) next to region A, region B is more concave than region C and region C is similarly more convex than region E. “A circular periphery of a certain lens element” refers to a circular periphery region of a surface on the lens element for light to pass through, that is, region C in the drawing. In the drawing, imaging light includes Lc (chief ray) and Lm (marginal ray). “A vicinity of the optical axis” refers to an optical axis region of a surface on the lens element for light to pass through, that is, the region A in  FIG. 19 . In addition, the lens element may include an extension part E for the lens element to be installed in an optical imaging lens set. Ideally speaking, no light would pass through the extension part, and the actual structure and shape of the extension part is not limited to this and may have other variations. For the reason of simplicity, the extension part is not illustrated in  FIGS. 1, 3, 5, 7, 9, 11, 13, 15 and 17 . 
     As shown in  FIG. 1 , the optical imaging lens set  1  of six lens elements of the present invention, sequentially located from an object side  2  (where an object is located) to an image side  3  along an optical axis  4 , has a first lens element  10 , a second lens element  20 , a third lens element  30 , a fourth lens element  40 , a fifth lens element  50 , a sixth lens element  60  and an image plane  71 . Generally speaking, the first lens element  10 , the second lens element  20 , the third lens element  30 , the fourth lens element  40 , the fifth lens element  50  and the sixth lens element  60  may be made of a transparent plastic material or glass and each has an appropriate refractive power, but the present invention is not limited to this. There are exclusively six lens elements with refractive power in the optical imaging lens set  1  of the present invention. The optical axis  4  is the optical axis of the entire optical imaging lens set  1 , and the optical axis of each of the lens elements coincides with the optical axis of the optical imaging lens set  1 . 
     Furthermore, the optical imaging lens set  1  includes an aperture stop (ape. stop)  80  disposed in an appropriate position. In  FIG. 1 , the aperture stop  80  is disposed between the third lens element  30  and the fourth lens element  40 . When light emitted or reflected by an object (not shown) which is located at the object side  2  enters the optical imaging lens set  1  of the present invention, it forms a clear and sharp image on the image plane  71  at the image side  3  after passing through the first lens element  10 , the second lens element  20 , the third lens element  30 , the aperture stop  80 , the fourth lens element  40 , the fifth lens element  50  and the sixth lens element  60 . 
     Each lens element in the optical imaging lens set  1  of the present invention has an object-side surface facing toward the object side  2  as well as an image-side surface facing toward the image side  3 . In addition, each object-side surface and image-side surface in the optical imaging lens set  1  of the present invention has a part in a vicinity of its circular periphery (circular periphery part) away from the optical axis  4  as well as a part in a vicinity of the optical axis (optical axis part) close to the optical axis  4 . For example, the first lens element  10  has a first object-side surface  11  and a first image-side surface  12 ; the second lens element  20  has a second object-side surface  21  and a second image-side surface  22 ; the third lens element  30  has a third object-side surface  31  and a third image-side surface  32 ; the fourth lens element  40  has a fourth object-side surface  41  and a fourth image-side surface  42 ; the fifth lens element  50  has a fifth object-side surface  51  and a fifth image-side surface  52 ; and the sixth lens element  60  has a sixth object-side surface  61  and a sixth image-side surface  62 . 
     Each lens element in the optical imaging lens set  1  of the present invention further has a central thickness on the optical axis  4 . For example, the first lens element  10  has a first lens element thickness T 1 , the second lens element  20  has a second lens element thickness T 2 , the third lens element  30  has a third lens element thickness T 3 , the fourth lens element  40  has a fourth lens element thickness T 4 , the fifth lens element  50  has a fifth lens element thickness T 5 , and the sixth lens element  60  has a sixth lens element thickness T 6 . Therefore, the total thickness of all the lens elements in the optical imaging lens set  1  along the optical axis  4  is ALT, ALT=T 1 +T 2 +T 3 +T 4 +T 5 +T 6 . 
     In addition, between two adjacent lens elements in the optical imaging lens set  1  of the present invention there is an air gap along the optical axis  4 . For example, an air gap G 12  is disposed between the first lens element  10  and the second lens element  20 , an air gap G 23  is disposed between the second lens element  20  and the third lens element  30 , an air gap G 34  is disposed between the third lens element  30  and the fourth lens element  40 , an air gap G 45  is disposed between the fourth lens element  40  and the fifth lens element  50 , and an air gap G 56  is disposed between the fifth lens element  50  and the sixth lens element  60 . Therefore, the sum of total five air gaps between adjacent lens elements from the first lens element  10  to the sixth lens element  60  along the optical axis  4  is Gaa, Gaa=G 12 +G 23 +G 34 +G 45 +G 56 . 
     In addition, the distance between the first object-side surface  11  of the first lens element  10  to the image plane  71 , namely the total length of the optical imaging lens set along the optical axis  4  is TTL; the effective focal length of the optical imaging lens set is EFL; the distance between the sixth image-side surface  62  of the six lens element  60  to the image plane  71  along the optical axis  4  is BFL. 
     FIRST EXAMPLE 
     Please refer to  FIG. 1  which illustrates the first example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 2A  for the longitudinal spherical aberration on the image plane  71  of the first example; please refer to  FIG. 2B  for the astigmatic field aberration on the sagittal direction; please refer to  FIG. 2C  for the astigmatic field aberration on the tangential direction, and please refer to  FIG. 2D  for the distortion aberration. The Y axis of the spherical aberration in each example is “field of view” for 1.0. The Y axis of the astigmatic field and the distortion in each example stand for “image height”. The image height is 3.0 mm. 
     The optical imaging lens set  1  of the first example has six lens elements  10  to  60 . The optical imaging lens set  1  also has an aperture stop  80  and an image plane  71 . The aperture stop  80  is provided between the third lens element  30  and the fourth lens element  40 . 
     The first lens element  10  has negative refractive power. The first object-side surface  11  facing toward the object side  2  is a convex surface, having a convex part  13  in the vicinity of the optical axis and a convex part  14  in a vicinity of its circular periphery; The first image-side surface  12  facing toward the image side  3  is a concave surface, having a concave part  16  in the vicinity of the optical axis and a concave part  17  in a vicinity of its circular periphery. 
     The second lens element  20  has negative refractive power. The second object-side surface  21  facing toward the object side  2  is a convex surface, having a convex part  23  in the vicinity of the optical axis and a convex part  24  in a vicinity of its circular periphery; The second image-side surface  22  facing toward the image side  3  is a concave surface, having a concave part  26  in the vicinity of the optical axis and a concave part  27  in a vicinity of its circular periphery. 
     The third lens element  30  has positive refractive power. The third object-side surface  31  facing toward the object side  2  has a convex part  33  in the vicinity of the optical axis and a concave part  34  in a vicinity of its circular periphery; The third image-side surface  32  facing toward the image side  3  is a convex surface, having a convex part  36  in the vicinity of the optical axis and a convex part  37  in a vicinity of its circular periphery. 
     The fourth lens element  40  has positive refractive power. The fourth object-side surface  41  facing toward the object side  2  is a convex surface, having a convex part  43  in the vicinity of the optical axis and a convex part  44  in a vicinity of its circular periphery; The fourth image-side surface  42  facing toward the image side  3  is a convex surface, having a convex part  46  in the vicinity of the optical axis and a convex part  47  in a vicinity of its circular periphery. 
     The fifth lens element  50  has positive refractive power. The fifth object-side surface  51  facing toward the object side  2  has a convex part  53  in the vicinity of the optical axis and a convex part  54  in a vicinity of its circular periphery; The fifth image-side surface  52  facing toward the image side  3  has a convex part  56  in the vicinity of the optical axis and a convex part  57  in a vicinity of its circular periphery. 
     The sixth lens element  60  has negative refractive power. The sixth object-side surface  61  facing toward the object side  2  has a concave part  63  in the vicinity of the optical axis and a concave part  64  in a vicinity of its circular periphery; The sixth image-side surface  62  facing toward the image side  3  has a concave part  66  in the vicinity of the optical axis and a concave part  67  in a vicinity of its circular periphery. 
     In the first example, the first lens element  10 , the fifth lens element  50  and the sixth lens element  60  are made of glass; the second lens element  20 , the third lens element  30  and the fourth lens element  40  are made of transparent plastic. The surfaces made of glass are all spherical surfaces; and the surface made of plastic, including object-side surfaces  21 / 31 / 41  and image-side surfaces  22 / 32 / 42  are all aspherical. These aspheric coefficients are defined according to the following formula: 
     
       
         
           
             
               Z 
               ⁡ 
               
                 ( 
                 Y 
                 ) 
               
             
             = 
             
               
                 
                   
                     Y 
                     2 
                   
                   R 
                 
                 / 
                 
                   ( 
                   
                     1 
                     + 
                     
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               1 
                               + 
                               K 
                             
                             ) 
                           
                           ⁢ 
                           
                             
                               Y 
                               2 
                             
                             
                               R 
                               2 
                             
                           
                         
                       
                     
                   
                   ) 
                 
               
               + 
               
                 
                   ∑ 
                   
                     i 
                     = 
                     1 
                   
                   n 
                 
                 ⁢ 
                 
                   
                     a 
                     
                       2 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       i 
                     
                   
                   × 
                   
                     Y 
                     
                       2 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       i 
                     
                   
                 
               
             
           
         
       
     
     In which: 
     R represents the curvature radius of the lens element surface; 
     Z represents the depth of an aspherical surface (the perpendicular distance between the point of the aspherical surface at a distance Y from the optical axis and the tangent plane of the vertex on the optical axis of the aspherical surface); 
     Y represents a vertical distance from a point on the aspherical surface to the optical axis; 
     K is a conic constant; and 
     a 2i  is the aspheric coefficient of the 2i order. 
     The optical data of the first example of the optical imaging lens set  1  are shown in  FIG. 22  while the aspheric surface data are shown in  FIG. 23 . In the present examples of the optical imaging lens set, the f-number (Fno) of the entire optical lens element system is 2.6, HFOV stands for the half field of view which is half of the field of view of the entire optical lens element system, and the unit for the curvature radius, the thickness and the focal length is in millimeters (mm). The length of the optical imaging lens set (the distance from the first object-side surface  11  of the first lens element  10  to the image plane  71 ) is 19.08 mm. The image height is 3.0 mm, HFOV is 64.534 degrees. Some important ratios of the first example are shown in  FIG. 40 . 
     SECOND EXAMPLE 
     Please refer to  FIG. 3  which illustrates the second example of the optical imaging lens set  1  of the present invention. It is worth noting that from the second example to the following examples, in order to simplify the figures, only the components different from what the first example has and the basic lens elements will be labeled in figures. Others components that are the same as what the first example has, such as the object-side surface, the image-side surface, the part in the vicinity of the optical axis and the part in a vicinity of its circular periphery will be omitted in the following example. Please refer to  FIG. 4A  for the longitudinal spherical aberration on the image plane  71  of the second example; please refer to  FIG. 4B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 4C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 4D  for the distortion aberration. The components in the second example are similar to those in the first example, but the optical data such as the lens material, the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the third object-side surface  31  of the third lens element  30  has a concave part  33 A in a vicinity of the optical axis, in addition, in this example, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the second example of the optical imaging lens set are shown in  FIG. 24  while the aspheric surface data are shown in  FIG. 25 . The length of the optical imaging lens set is 19.13 mm. The image height is 3.0 mm, HFOV is 62.205 degrees, and Fno is 2.4. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having larger HFOV so as to increase the shooting view, having larger aperture, having better imaging quality, being easier to produce and having higher yield. 
     THIRD EXAMPLE 
     Please refer to  FIG. 5  which illustrates the third example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 6A  for the longitudinal spherical aberration on the image plane  71  of the third example; please refer to  FIG. 6B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 6C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 6D  for the distortion aberration. The components in the third example are similar to those in the first example, but the optical data such as the lens material, the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the fifth lens element  50  and the sixth lens element  60  are made of glass; the first lens element  10 , the second lens element  20 , the third lens element  30  and the fourth lens element  40  are made of transparent plastic, wherein each surface made of plastic are defined according to the formula mentioned above. In addition, in this example, the fourth object-side surface  41  of the fourth lens element  40  has a concave part  43 B in the vicinity of the optical axis and a concave part  44 B in a vicinity of its circular periphery. The optical data of the third example of the optical imaging lens set are shown in  FIG. 26  while the aspheric surface data are shown in  FIG. 27 . The length of the optical imaging lens set is 19.96 mm. The image height is 3.0 mm, HFOV is 62.182 degrees, and Fno is 2.6. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as being easier to produce and having higher yield. 
     FOURTH EXAMPLE 
     Please refer to  FIG. 7  which illustrates the fourth example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 8A  for the longitudinal spherical aberration on the image plane  71  of the fourth example; please refer to  FIG. 8B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 8C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 8D  for the distortion aberration. The components in the fourth example are similar to those in the first example, but the optical data such as the lens material, the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, only the fifth lens element  50  is made of glass; the first lens element  10 , the second lens element  20 , the third lens element  30 , the fourth lens element  40  and the sixth lens element  60  are made of transparent plastic, wherein each surface made of plastic are defined according to the formula mentioned above. In addition, in this example, the fourth object-side surface  41  of the fourth lens element  40  has a concave part  44 C in a vicinity of its circular periphery; the fifth object-side surface  51  of the fifth lens element  50  has a concave part  53 C in the vicinity of the optical axis and a concave part  54 C in a vicinity of its circular periphery; the sixth image-side surface  62  of the sixth lens element  60  has a convex part  66 C in the vicinity of the optical axis. The optical data of the fourth example of the optical imaging lens set are shown in  FIG. 28  while the aspheric surface data are shown in  FIG. 29 . The length of the optical imaging lens set is 20.51 mm. The image height is 3.0 mm, HFOV is 62.893 degrees, and Fno is 2.6. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having better imaging quality, being easier to produce and having higher yield. 
     FIFTH EXAMPLE 
     Please refer to  FIG. 9  which illustrates the fifth example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 10A  for the longitudinal spherical aberration on the image plane  71  of the fifth example; please refer to  FIG. 10B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 10C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 10D  for the distortion aberration. The components in the fifth example are similar to those in the first example, but the optical data such as the lens material, the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the fifth lens element  50  and the sixth lens element  60  are made of glass; the first lens element  10 , the second lens element  20 , the third lens element  30  and the fourth lens element  40  are made of transparent plastic, wherein each surface made of plastic are defined according to the formula mentioned above. In addition, in this example, the third object-side surface  31  of the third lens element  30  has a convex part  34 D in a vicinity of its circular periphery, the third image-side surface  32  of the third lens element  30  has a concave part  36 D in the vicinity of the optical axis and a concave part  37 D in a vicinity of its circular periphery. Besides, it is worth noting, in this example, the aperture stop is disposed in a different position, more precisely, in this example, an aperture stop  80 ′ is disposed between the second lens element  20  and the third lens element  30 . Furthermore, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the fifth example of the optical imaging lens set are shown in  FIG. 30  while the aspheric surface data are shown in  FIG. 31 . The length of the optical imaging lens set is 78.80 mm. The image height is 3.0 mm, HFOV is 60.0 degrees, and Fno is 2.6. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having better imaging quality, being easier to produce and having higher yield. 
     SIXTH EXAMPLE 
     Please refer to  FIG. 11  which illustrates the sixth example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 12A  for the longitudinal spherical aberration on the image plane  71  of the sixth example; please refer to  FIG. 12B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 12C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 12D  for the distortion aberration. The components in the sixth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the sixth example of the optical imaging lens set are shown in  FIG. 32  while the aspheric surface data are shown in  FIG. 33 . The length of the optical imaging lens set is 19.80 mm. The image height is 3.05 mm, HFOV is 59.169 degrees, and Fno is 2.4. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having larger aperture, having better imaging quality, being easier to produce and having higher yield. 
     SEVENTH EXAMPLE 
     Please refer to  FIG. 13  which illustrates the seventh example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 14A  for the longitudinal spherical aberration on the image plane  71  of the seventh example; please refer to  FIG. 14B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 14C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 14D  for the distortion aberration. The components in the seventh example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the sixth image-side surface  62  of the sixth lens element  60  has a convex part  66 E in the vicinity of the optical axis. Besides, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the seventh example of the optical imaging lens set are shown in  FIG. 34  while the aspheric surface data are shown in  FIG. 35 . The length of the optical imaging lens set is 18.94 mm. The image height is 3.05 mm, HFOV is 56.919 degrees, and Fno is 2.4. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having shorter total length, having larger aperture, having better imaging quality, being easier to produce and having higher yield. 
     EIGHTH EXAMPLE 
     Please refer to  FIG. 15  which illustrates the eighth example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 16A  for the longitudinal spherical aberration on the image plane  71  of the eighth example; please refer to  FIG. 16B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 16C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 16D  for the distortion aberration. The components in the eighth example are similar with those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the eighth example of the optical imaging lens set are shown in  FIG. 36  while the aspheric surface data are shown in  FIG. 37 . The length of the optical imaging lens set is 19.50 mm. The image height is 3.05 mm, HFOV is 62.725 degrees, and Fno is 2.4. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having larger aperture, having better imaging quality, being easier to produce and having higher yield. 
     NINTH EXAMPLE 
     Please refer to  FIG. 17  which illustrates the ninth example of the optical imaging lens set  1  of the present invention. Please refer to  FIG. 18A  for the longitudinal spherical aberration on the image plane  71  of the ninth example; please refer to  FIG. 18B  for the astigmatic aberration on the sagittal direction; please refer to  FIG. 18C  for the astigmatic aberration on the tangential direction, and please refer to  FIG. 18D  for the distortion aberration. The components in the ninth example are similar with those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the fifth lens element  50  and the sixth lens element  60  are cemented to each other. The optical data of the ninth example of the optical imaging lens set are shown in  FIG. 38  while the aspheric surface data are shown in  FIG. 39 . The length of the optical imaging lens set is 20.50 mm. The image height is 3.05 mm, HFOV is 58.823 degrees, and Fno is 2.4. Some important ratios of the first example are shown in  FIG. 40 . 
     It is worth noting, compared with the first example, this example has some advantages such as having larger aperture, having better imaging quality, being easier to produce and having higher yield. 
     Following is the definitions of each parameter mentioned above and some other parameters which are not disclosed in the examples of the present invention, shown as TABLE 1: 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Parameter 
                 Definition 
               
               
                   
               
             
            
               
                 T1 
                 The thickness of the first lens element along the optical 
               
               
                   
                 axis 
               
               
                 G12 
                 The distance between the first lens element and the second 
               
               
                   
                 lens element along the optical axis 
               
               
                 T2 
                 The thickness of the second lens element along the optical 
               
               
                   
                 axis 
               
               
                 G23 
                 The distance between the second lens element and the third 
               
               
                   
                 lens element along the optical axis 
               
               
                 T3 
                 The thickness of the third lens element along the optical 
               
               
                   
                 axis 
               
               
                 G34 
                 The distance between the third lens element and the fourth 
               
               
                   
                 lens element along the optical axis 
               
               
                 T4 
                 The thickness of the fourth lens element along the optical 
               
               
                   
                 axis 
               
               
                 G45 
                 The distance between the fourth lens element and the fifth 
               
               
                   
                 lens element along the optical axis 
               
               
                 T5 
                 The thickness of the fifth lens element along the optical 
               
               
                   
                 axis 
               
               
                 G56 
                 The distance between the fifth lens element and the sixth 
               
               
                   
                 lens element along the optical axis 
               
               
                 T6 
                 The thickness of the sixth lens element along the optical 
               
               
                   
                 axis 
               
               
                 G6F 
                 The distance between the sixth image-side surface of the 
               
               
                   
                 sixth lens element to the filter along the optical axis 
               
               
                 TF 
                 The thickness of the filter along the optical axis 
               
               
                 GFP 
                 The distance between the filter to the image plane along 
               
               
                   
                 the optical axis 
               
               
                 f1 
                 The focal length of the first lens element 
               
               
                 f2 
                 The focal length of the second lens element 
               
               
                 f3 
                 The focal length of the third lens element 
               
               
                 f4 
                 The focal length of the fourth lens element 
               
               
                 f5 
                 The focal length of the fifth lens element 
               
               
                 f6 
                 The focal length of the sixth lens element 
               
               
                 n1 
                 The refractive index of the first lens element 
               
               
                 n2 
                 The refractive index of the second lens element 
               
               
                 n3 
                 The refractive index of the third lens element 
               
               
                 n4 
                 The refractive index of the fourth lens element 
               
               
                 n5 
                 The refractive index of the fifth lens element 
               
               
                 n6 
                 The refractive index of the sixth lens element 
               
               
                 ν1 
                 The Abbe number of the first lens element 
               
               
                 ν2 
                 The Abbe number of the second lens element 
               
               
                 ν3 
                 The Abbe number of the third lens element 
               
               
                 ν4 
                 The Abbe number of the fourth lens element 
               
               
                 ν5 
                 The Abbe number of the fifth lens element 
               
               
                 ν6 
                 The Abbe number of the sixth lens element 
               
               
                 EFL 
                 The effective focal length of the optical imaging lens 
               
               
                   
                 set 
               
               
                 TTL 
                 The distance between the first object-side surface of the 
               
               
                   
                 first lens element to the image plane 
               
               
                 ALT 
                 The total thickness of all the lens elements in the optical 
               
               
                   
                 imaging lens set along the optical axis 
               
               
                 Gaa 
                 The sum of total five air gaps between adjacent lens 
               
               
                   
                 elements from the first lens element to the sixth lens 
               
               
                   
                 element along the optical axis 
               
               
                 BFL 
                 The distance between the image-side surface of the sixth 
               
               
                   
                 lens element to the image plane along the optical axis 
               
               
                   
               
            
           
         
       
     
     The applicant summarized the efficacy of each embodiment mentioned above as follows: 
     In the present invention, all of the longitudinal spherical aberration, the astigmatism aberration and the distortion are in compliance with the using standard. In addition, the off-axis light of red, blue and green wavelengths are focused on the vicinity of the imaging point in different heights, therefore the deviation between each off-axis light and the imaging point is well controlled, so as to have good suppression for spherical aberration, aberration and distortion. Furthermore, the curves of red, blue and green wavelengths are very close to each other, meaning that the dispersion on the axis has greatly improved too. In summary, the different lens elements of the present invention are matched to each other, to achieve good image quality. 
     In addition, the inventors discover that there are some better ratio ranges for different data according to the above various important ratios are shown as below in TABLE 2. Better ratio ranges help the designers to design the better optical performance and an effectively reduced length of a practically possible optical imaging lens set. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Relationship 
                 Lower limit 
                 Upper limit 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 (G23 + G34)/(G45 + G56) 
                 9.00 
                 600.00 
               
               
                   
                 ALT/G23 
                 0.20 
                 6.00 
               
               
                   
                 ALT/T5 
                 5.26 
                 10.38 
               
               
                   
                 BFL/G12 
                 0.85 
                 34.53 
               
               
                   
                 BFL/G23 
                 0.10 
                 1.16 
               
               
                   
                 BFL/T2 
                 0.76 
                 4.34 
               
               
                   
                 BFL/T5 
                 1.33 
                 3.91 
               
               
                   
                 Gaa/G12 
                 2.00 
                 50.00 
               
               
                   
                 Gaa/G23 
                 0.93 
                 2.55 
               
               
                   
                 Gaa/G34 
                 3.50 
                 17.00 
               
               
                   
                 TTL/G23 
                 1.40 
                 10.00 
               
               
                   
                 TTL/T1 
                 3.47 
                 23.76 
               
               
                   
                 TTL/T2 
                 4.00 
                 26.00 
               
               
                   
                   
               
            
           
         
       
     
     It is worth noting that, in view of the unpredictability of the optical system design, under the structure of the invention, by controlling the parameters, can help the designer to design the optical imaging lens set with good optical performance, having shorter total length, and being feasible in manufacturing process. Each parameter has its preferred range. TABLE 2 shows the preferred range lower limit and range upper limit of each relationship mentioned in the present invention. 
     The optical imaging lens set  1  of the present invention may be applied to an electronic device, such as game consoles or driving recorders. Please refer to  FIG. 20 .  FIG. 20  illustrates a first preferred example of the optical imaging lens set  1  of the present invention for use in a portable electronic device  100 . The electronic device  100  includes a case  110 , and an image module  120  mounted in the case  110 . A driving recorder is illustrated in  FIG. 16  as an example, but the electronic device  100  is not limited to a driving recorder. 
     As shown in  FIG. 20 , the image module  120  includes the optical imaging lens set  1  as described above.  FIG. 20  illustrates the aforementioned first example of the optical imaging lens set  1 . In addition, the portable electronic device  100  also contains a barrel  130  for the installation of the optical imaging lens set  1 , a module housing unit  140  for the installation of the barrel  130 , a substrate  172  for the installation of the module housing unit  140  and an image sensor  70  disposed at the substrate  172 , and at the image side  3  of the optical imaging lens set  1 . The image sensor  70  in the optical imaging lens set  1  may be an electronic photosensitive element, such as a charge coupled device or a complementary metal oxide semiconductor element. The image plane  71  forms at the image sensor  70 . 
     The image sensor  70  used here is a product of chip on board (COB) package rather than a product of the conventional chip scale package (CSP) so it is directly attached to the substrate  172 , and protective glass is not needed in front of the image sensor  70  in the optical imaging lens set  1 , but the present invention is not limited to this. 
     To be noticed in particular, the case  110 , the barrel  130 , and/or the module housing unit  140  may be a single element or consist of a plurality of elements, but the present invention is not limited to this. 
     Each one of the six lens elements  10 ,  20 ,  30 ,  40 ,  50  and  60  with refractive power is installed in the barrel  130  with air gaps disposed between two adjacent lens elements in an exemplary way. The module housing unit  140  has a lens element housing  141 , and an image sensor housing  146  installed between the lens element housing  141  and the image sensor  70 . However in other examples, the image sensor housing  146  is optional. The barrel  130  is installed coaxially along with the lens element housing  141  along the axis I-I′, and the barrel  130  is provided inside of the lens element housing  141 . 
     Please also refer to  FIG. 21  for another application of the aforementioned optical imaging lens set  1  in a portable electronic device  200  in the second preferred example. The main differences between the portable electronic device  200  in the second preferred example and the portable electronic device  100  in the first preferred example are: the lens element housing  141  has a first seat element  142 , a second seat element  143 , a coil  144  and a magnetic component  145 . The first seat element  142  is for the installation of the barrel  130 , exteriorly attached to the barrel  130  and disposed along the axis I-I′. The second seat element  143  is disposed along the axis I-I′ and surrounds the exterior of the first seat element  142 . The coil  144  is provided between the outside of the first seat element  142  and the inside of the second seat element  143 . The magnetic component  145  is disposed between the outside of the coil  144  and the inside of the second seat element  143 . 
     The first seat element  142  may pull the barrel  130  and the optical imaging lens set  1  which is disposed inside of the barrel  130  to move along the axis I-I′, namely the optical axis  4  in  FIG. 1 . The image sensor housing  146  is attached to the second seat element  143 . Other details of the portable electronic device  200  in the second preferred example are similar to those of the portable electronic device  100  in the first preferred example so they are not elaborated again. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.