Patent Publication Number: US-11656438-B2

Title: Mobile device and optical imaging lens thereof

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/417,239, filed May 20, 2019, which is a continuation of U.S. patent application Ser. No. 15/092,436, filed on Apr. 6, 2016, now U.S. Pat. No. 10,345,553, which is a continuation of U.S. patent application Ser. No. 14/194,123, filed on Feb. 28, 2014, now U.S. Pat. No. 9,341,819, which claims priority from China Patent Application No. 201310403008.8, filed on Sep. 6, 2013, the contents of which are hereby incorporated by reference in their entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a mobile device and an optical imaging lens thereof, and particularly, relates to a mobile device applying an optical imaging lens having six lens elements and an optical imaging lens thereof. 
     BACKGROUND OF THE INVENTION 
     The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. has correspondingly triggered a growing need for smaller sized photography modules comprising elements such as an optical imaging lens, a module housing unit, and an image sensor, etc., contained therein. Size reductions may be contributed from various aspects of the mobile devices, which include not only the charge coupled device (CCD) and the complementary metal-oxide semiconductor (CMOS), but also the optical imaging lens mounted therein. When reducing the size of the optical imaging lens, however, achieving good optical characteristics becomes a challenging problem. 
     The length of conventional optical imaging lenses comprising four lens elements can be limited in a certain range; however, as the more and more demands in the market for high-end products, high-standard optical imaging lenses, such as the optical imaging lenses comprising six lens elements, which show great quality with more pixels are required. 
     U.S. Pat. No. 8,355,215 disclosed an optical imaging lens constructed with an optical imaging lens having six lens elements. The length of the optical imaging lens of patent &#39;215, which, from the object-side surface of the first lens element to the image plane, is about 2 cm. Although the image quality of the optical imaging lens is acceptable, the volume of the optical imaging lens is too large to be suitable for small sized electronic device with the size between 1 cm and 2 cm. 
     Additionally, U.S. Pat. No. 8,432,619 disclosed an optical imaging lens constructed with an optical imaging lens having six lens elements. Although, the length of the optical imaging lens is reduced to 0.5 cm, which meets the demand of small sized product design, the image distortion of the optical imaging lens of patent &#39;619 reaches 25%, and which means the image quality is too poor to meet specification requirements of consumer electronic products. 
     Therefore, there is needed to develop an optical imaging lens having six lens elements for high specification products. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a mobile device and an optical imaging lens thereof. With controlling the convex or concave shape of the surfaces of the lens elements, the length of the optical imaging lens is shortened and meanwhile the good optical characteristics, such as high resolution, are sustained. 
     In an exemplary embodiment, an optical imaging lens, sequentially from an object side to an image side, comprises first, second, third, fourth, fifth and sixth lens elements, each of said lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, in which the first lens element has a positive refractive power; the object-side surface of the second lens element comprises a convex portion in a vicinity of the optical axis; the object-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis, and the image-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis; the image-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis; the image-side surface of the sixth lens element comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the sixth lens element; and the optical imaging lens as a whole comprises only the six lens elements having refractive power. 
     In an exemplary embodiment, some equation(s), such as those relating to the ratio among parameters could be taken into consideration. For example, the sum of all five air gaps from the first lens element to the sixth lens element along the optical axis, Gaa, and an air gap between the fourth lens element and the fifth lens element along the optical axis, G45, could be controlled to satisfy the equation as follows:
 
( Gaa/G 45)≤21.0  Equation (1).
 
     In another exemplary embodiment, the sum of the thickness of all six lens elements along the optical axis, ALT, and an air gap between the second lens element and the third lens element along the optical axis, G23, could be controlled to satisfy the equation as follows:
 
 ALT/G 23≤55.0  Equation (2).
 
     In another exemplary embodiment, a central thickness of the fifth lens element along the optical axis, T5, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 5≤3.85  Equation (3).
 
     In another exemplary embodiment, a central thickness of the third lens element along the optical axis, T3, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 3≤6.5  Equation (4).
 
     In another exemplary embodiment, a central thickness of the sixth lens element along the optical axis, T6, and ALT could be controlled to satisfy the equation as follows:
 
 ALT/T 6≤8.5  Equation (5).
 
     In another exemplary embodiment, a distance from the object-side surface of the first lens element to the image side of the optical imaging lens along the optical axis, i.e. the system length of the optical imaging lens, TTL, and a central thickness of the first lens element along the optical axis T1, could be controlled to satisfy the equation as follows:
 
 TTL/T 1≤11.5  Equation (6).
 
     In another exemplary embodiment, an air gap between the fifth lens element and the sixth lens element along the optical axis, G56, and ALT could be controlled to satisfy the equation as follows:
 
 ALT/G 56≤30.0  Equation (7).
 
     In another exemplary embodiment, a central thickness of the second lens element along the optical axis, T2, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 2≤5.5  Equation (8).
 
     In another exemplary embodiment, a central thickness of the first lens element along the optical axis, T1, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 1≤3.8  Equation (9).
 
     In another exemplary embodiment, T2 and T5 could be controlled to satisfy the equation as follows:
 
 T 2&gt; T 5  Equation (10).
 
     Aforesaid exemplary embodiments are not limited and could be selectively incorporated in other embodiments described herein. 
     In another exemplary embodiment, a mobile device comprises a housing and a photography module. The photography module is positioned in the housing and comprises a lens barrel, an optical imaging lens, a module housing unit, and an image sensor. The optical image lens is positioned in the lens barrel. The module housing unit is configured to provide a space where the lens barrel is positioned. The image sensor is positioned at the image side of the optical imaging lens. 
     Through controlling the arrangement of the convex or concave shape of the surface of the lens element(s) and/or refractive power, the mobile device and the optical imaging lens thereof in aforesaid exemplary embodiments achieve good optical characteristics and effectively shorten the lengths of the optical imaging lens. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
         FIG.  1    is a cross-sectional view of one single lens element of one embodiment of an optical imaging lens according to the present disclosures; 
         FIG.  2    is a cross-sectional view of a first embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  3    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a first embodiment of the optical imaging lens according to the present disclosures; 
         FIG.  4    is a table of optical data for each lens element of a first embodiment of the optical imaging lens of the present disclosures; 
         FIG.  5    is a table of aspherical data of a first embodiment of the optical imaging lens according to the present disclosures; 
         FIG.  6    is a cross-sectional view of a second embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  7    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a second embodiment of the optical imaging lens disclosures; 
         FIG.  8    is a table of optical data for each lens element of a second embodiment of the optical imaging lens of the present disclosures; 
         FIG.  9    is a table of aspherical data of a second embodiment of the optical imaging lens according to the present disclosures; 
         FIG.  10    is a cross-sectional view of a third embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  11    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a third embodiment of the optical imaging lens according the present disclosures; 
         FIG.  12    is a table of optical data for each lens element of a third embodiment of the optical imaging lens according the present disclosures; 
         FIG.  13    is a table of aspherical data of a third embodiment of the optical imaging lens according the present disclosures; 
         FIG.  14    is a cross-sectional view of a fourth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  15    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a fourth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  16    is a table of optical data for each lens element of a fourth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  17    is a table of aspherical data of a fourth embodiment of the optical imaging lens according to the present disclosures; 
         FIG.  18    is a cross-sectional view of a fifth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  19    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a fifth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  20    is a table of optical data for each lens element of a fifth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  21    is a table of aspherical data of a fifth embodiment of the optical imaging lens according to the present disclosures; 
         FIG.  22    is a cross-sectional view of a sixth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  23    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a sixth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  24    is a table of optical data for each lens element of a sixth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  25    is a table of aspherical data of a sixth embodiment of the optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  26    is a cross-sectional view of a seventh embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  27    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a seventh embodiment of the optical imaging lens according the present disclosures; 
         FIG.  28    is a table of optical data for each lens element of a seventh embodiment of the optical imaging lens according the present disclosures; 
         FIG.  29    is a table of aspherical data of a seventh embodiment of the optical imaging lens according the present disclosures; 
         FIG.  30    is a cross-sectional view of an eighth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  31    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of an eighth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  32    is a table of optical data for each lens element of an eighth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  33    is a table of aspherical data of an eighth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  34    is a cross-sectional view of a ninth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  35    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a ninth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  36    is a table of optical data for each lens element of a ninth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  37    is a table of aspherical data of a ninth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  38    is a cross-sectional view of a tenth embodiment of an optical imaging lens having six lens elements according to the present disclosures; 
         FIG.  39    is a chart of longitudinal spherical aberration and other kinds of optical aberrations of a tenth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  40    is a table of optical data for each lens element of a tenth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  41    is a table of aspherical data of a tenth embodiment of the optical imaging lens according the present disclosures; 
         FIG.  42    is a table for the values of TTL, ALT, Gaa, Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 of all ten example embodiments; 
         FIG.  43    is a structure of an example embodiment of a mobile device; and 
         FIG.  44    is a partially enlarged view of the structure of another example embodiment of a mobile device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features. Persons having ordinary skill in the art will understand other varieties for implementing example embodiments, including those described herein. The drawings are not limited to specific scale and similar reference numbers are used for representing similar elements. As used in the disclosures and the appended claims, the terms “example embodiment,” “exemplary embodiment,” and “present embodiment” do not necessarily refer to a single embodiment, although it may, and various example embodiments may be readily combined and interchanged, without departing from the scope or spirit of the present invention. Furthermore, the terminology as used herein is for the purpose of describing example embodiments only and is not intended to be a limitation of the invention. In this respect, as used herein, the term “in” may include “in” and “on”, and the terms “a”, “an” and “the” may include singular and plural references. Furthermore, as used herein, the term “by” may also mean “from”, depending on the context. Furthermore, as used herein, the term “if” may also mean “when” or “upon”, depending on the context. Furthermore, as used herein, the words “and/or” may refer to and encompass any and all possible combinations of one or more of the associated listed items. 
     Here in the present disclosures, the description “a lens element has a positive refractive power (or a negative refractive power)” means a portion of the lens has a positive refractive power (or a negative refractive power) in a vicinity of the optical axis. Furthermore, as used herein, the description “an object-side (or the image-side) surface of a lens element comprises a convex portion (or a concave portion) in a certain region” means the object-side (or image-side) surface of the lens element “protrudes outwardly (or depresses inwardly)” along the direction parallel to the optical axis at the specific region, compared with the outer region radially adjacent to the specific region. As shown in  FIG.  1   , the axis I represents the optical axis and the lens element is radially symmetric about the axis I. The object-side surface of the lens element comprises a convex portion at the region A, a concave portion at the region B, and another convex portion at the region C. This is because compared with the outer region radially adjacent to the region A (i.e. region B), the object-side surface protrudes outwardly at the region A, compared with the region C, the object-side surface depresses inwardly at the region B, and compared with the region E, the object-side surface protrudes outwardly at the region C. Here, “in a vicinity of a periphery of a lens element” means that in a vicinity of the peripheral region of a surface for passing imaging light on the lens element, i.e. the region C as shown in  FIG.  1   . The imaging light comprises chief ray Lc and marginal ray Lm. “In a vicinity of the optical axis” means that in a vicinity of the optical axis of a surface for passing the imaging light on the lens element, i.e. the region A as shown in  FIG.  1   . Further, a lens element could comprise an extending portion E for mounting the lens element in an optical imaging lens. Ideally, the imaging light would not pass the extending portion E. Here the extending portion E is only for example, the structure and shape thereof are not limited to this specific example. Please also noted that the extending portion of all the lens elements in the example embodiments shown below are skipped for maintaining the drawings clean and concise. 
     Example embodiments of an optical imaging lens may comprise a first lens element, an aperture stop, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element, in which each of the lens elements has refracting power, an object-side surface facing toward an object side and an image-side surface facing toward an image side. These lens elements may be arranged sequentially from the object side to the image side along an optical axis, and example embodiments of the lens as a whole may comprise only the six lens elements having refracting power. In an example embodiment: the first lens element has a positive refractive power; the object-side surface of the second lens element comprises a convex portion in a vicinity of the optical axis; the object-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis, and the image-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis; the image-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis; and the image-side surface of the sixth lens element comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the sixth lens element. 
     Preferably, the lens elements in aforesaid exemplary embodiments are designed in light of the optical characteristics and the lengths of the optical imaging lens. For example, the first lens element having a positive refractive power may assist in collecting light for the system, and combining this with an aperture stop positioned between the first and second lens elements may reduce the length of the optical imaging lens and maintain good imaging quality. In conjunction with the above-mention design on the surfaces of the lens elements, the object-side surface of the second lens element comprising a convex portion in a vicinity of the optical axis, the object-side surface of the third lens element comprising a concave portion in a vicinity of the optical axis, the image-side surface of the third lens element comprising a concave portion in a vicinity of the optical axis, and the image-side surface of the fourth lens element comprising a convex portion in a vicinity of the optical axis may eliminate the aberration. Further, the image-side surface of the sixth lens element comprising a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the sixth lens element may correct the field curvature of the optical imaging lens, reduce the high order aberration of the optical imaging lens, and depresses the angle of the chief ray (the incident angle of the light onto the image sensor), and then the sensitivity of the whole system is promoted to promote the image quality of the optical imaging lens. 
     In another exemplary embodiment, the ratio of related parameters of the optical imaging lens could be controlled to satisfy equations for assisting the designer to design the optical imaging lens with good optical characteristics and short total length under practicable technic, such as the sum of all five air gaps from the first lens element to the sixth lens element along the optical axis, Gaa, and an air gap between the fourth lens element and the fifth lens element along the optical axis, G45, could be controlled to satisfy the equation as follows:
 
( Gaa/G 45)≤21.0  Equation (1).
 
     In another exemplary embodiment, the sum of the thickness of all six lens elements along the optical axis, ALT, and an air gap between the second lens element and the third lens element along the optical axis, G23, could be controlled to satisfy the equation as follows:
 
 ALT/G 23≤55.0  Equation(2).
 
     In another exemplary embodiment, a central thickness of the fifth lens element along the optical axis, T5, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 5≤3.85  Equation (3).
 
     In another exemplary embodiment, a central thickness of the third lens element along the optical axis, T3, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 3≤6.5  Equation (4).
 
     In another exemplary embodiment, a central thickness of the sixth lens element along the optical axis, T6, and ALT could be controlled to satisfy the equation as follows:
 
 ALT/T 6≤8.5  Equation (5).
 
     In another exemplary embodiment, a distance from the object-side surface of the first lens element to the image side of the optical imaging lens along the optical axis, i.e. the system length of the optical imaging lens, TTL, and a central thickness of the first lens element along the optical axis, T1, could be controlled to satisfy the equation as follows:
 
 TTL/T 1≤11.5  Equation (6).
 
     In another exemplary embodiment, an air gap between the fifth lens element and the sixth lens element along the optical axis, G56, and ALT could be controlled to satisfy the equation as follows:
 
 ALT/G 56≤30.0  Equation (7).
 
     In another exemplary embodiment, a central thickness of the second lens element along the optical axis, T2, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 2≤5.5  Equation (8).
 
     In another exemplary embodiment, a central thickness of the first lens element along the optical axis, T1, and Gaa could be controlled to satisfy the equation as follows:
 
 Gaa/T 1≤3.8  Equation (9).
 
     In another exemplary embodiment, T2 and T5 could be controlled to satisfy the equation as follows:
 
 T 2&gt; T 5  Equation (10).
 
     Aforesaid exemplary embodiments are not limited and could be selectively incorporated in other embodiments described herein. 
     Reference is now made to Equation (1). The shortened ratio of Gaa is greater than that of G45, which could effectively shorten the length of the optical imaging lens, and then could reduce the whole volume, such that which is favorable for endeavoring slimmer mobile devices. When Gaa/G45 meets to Equation (1), the optical imaging lens would have good optical characteristics. More preferably, the value of Gaa/G45 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
(5.0≤ Gaa/G 45)≤21.0  Equation (1′).
 
     Reference is now made to Equation (2). The shortened ratio of G23 is smaller than that of ALT, and meanwhile the optical characteristics and the fabrication ability should be considered. Therefore, when ALT/G23 meets to Equation (2), the sum of the thickness of all six lens elements along the optical axis, ALT, and the air gap between the second lens element and the third lens element along the optical axis, G23, could be maintained in a proper range. More preferably, the value of ALT/G23 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
8.0≤ ALT/G 23≤55.0  Equation (2′).
 
     Reference is now made to Equation (3). The shortened ratio of Gaa is greater than that of T5, which could effectively shorten the length of the optical imaging lens, and then could reduce the whole volume, such that which is favorable for endeavoring slimmer mobile devices. When Gaa/T5 meets to Equation (3), the optical imaging lens would have good optical characteristics. More preferably, the value of Gaa/T5 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
1.0≤ Gaa/T 5≤3.85  Equation (3′).
 
     Reference is now made to Equation (4). The shortened ratio of Gaa is greater than that of T3, which could effectively shorten the length of the optical imaging lens, and then could reduce the whole volume, such that which is favorable for endeavoring slimmer mobile devices. When Gaa/T3 meets to Equation (4), the optical imaging lens would have good optical characteristics. More preferably, the value of Gaa/T3 should be further restricted by a lower limit, for example but not limited to the equation as follows:
 
5.0≤ Gaa/T 3≤6.5  Equation (4′).
 
     Reference is now made to Equation (5). Generally, the shortened ratio of T6 is limited by the greater effective radius of the sixth lens element for passing imaging light. Therefore, the shorting ratio of ALT is greater than that of T6. When ALT/T6 meets to Equation (5), the optical imaging lens would have good optical characteristics. More preferably, the value of ALT/T6 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
5.0≤ ALT/T 6≤8.5  Equation (5′).
 
     Reference is now made to Equation (6). Generally, the first lens element has to provide the positive refractive power of the optical imaging lens, such that the shortened ratio of T1 is smaller than that of TTL. When TTL/T1 meets to Equation (6), the optical imaging lens would have good optical characteristics. More preferably, the value of TTL/T1 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
8.0≤ TTL/T 1≤11.5  Equation (6′).
 
     Reference is now made to Equation (7). The shortened ratio of G56 is smaller than that of ALT, and meanwhile the optical characteristics and the fabrication ability should be considered. Therefore, when ALT/G56 meets to Equation (7), the sum of the thickness of all six lens elements along the optical axis, ALT, and the air gap between the fifth lens element and the sixth lens element along the optical axis, G56, could be maintained in a proper range. More preferably, the value of ALT/G56 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
2.5≤ ALT/G 56≤30.0  Equation (7′).
 
     Reference is now made to Equation (8). The shortened ratio of Gaa is greater than that of T2, which could effectively shorten the length of the optical imaging lens, and then could reduce the whole volume, such that which is favorable for endeavoring slimmer mobile devices. When Gaa/T2 meets to Equation (8), the optical imaging lens would have good optical characteristics. More preferably, the value of Gaa/T2 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
1.5≤ Gaa./T 2≤5.5  Equation (8′).
 
     Reference is now made to Equation (9). Generally, the first lens element has to provide the positive refractive power of the optical imaging lens, such that the shortened ratio of T1 is smaller than that of Gaa. When Gaa/T1 meets to Equation (9), the optical imaging lens would have good optical characteristics. More preferably, the value of Gaa/T1 should be further restricted by a lower limit, for example but not limited to, the equation as follows:
 
2.0≤ Gaa/T 1≤3.8  Equation (9′).
 
     When T2 and T5 meet to Equation (10), the optical imaging lens would have good optical characteristics. 
     When implementing example embodiments, more details about the convex or concave surface structure and/or the refractive power may be incorporated for one specific lens element or broadly for plural lens elements to enhance the control for the system performance and/or resolution, as illustrated in the following embodiments. It is noted that the details listed here could be incorporated in example embodiments if no inconsistency occurs. 
     Several exemplary embodiments and associated optical data will now be provided for illustrating example embodiments of optical imaging lens with good optical quality and a shortened length. Reference is now made to  FIGS.  2 - 5   .  FIG.  2    illustrates a cross-sectional view of a first embodiment of the optical imaging lens  1  having six lens elements according to the present disclosures.  FIGS.  3 ( a ) to  3 ( d )  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  1  according to an example embodiment.  FIG.  4    illustrates an example table of optical data of each lens element of the optical imaging lens  1  according to an example embodiment.  FIG.  5    depicts an example table of aspherical data of the optical imaging lens  1  according to an example embodiment. 
     As shown in  FIG.  2   , the optical imaging lens  1  of the present embodiment comprises, in order from an object side A 1  to an image side A 2 , a first lens element  110 , an aperture stop  100 , a second lens element  120 , a third lens element  130 , a fourth lens element  140 , a fifth lens element  150 , and the sixth lens element  160 . The aperture stop  100  may be also disposed between the first lens element  110  and the second element  120  or other position. A filtering unit  170  and an image plane  180  of an image sensor are positioned at the image side A 2  of the optical image lens  1 . More specifically, the filtering unit  170  is an IR cut filter (infrared cut filter) positioned between the sixth lens  160  and the image plane  180  of the image sensor. The filtering unit  170  selectively absorbs light with specific wavelength from the light passing optical imaging lens  1 . For example, IR light is absorbed, and this will prohibit the IR light which is not seen by human eyes from producing an image on the image plane  180 . 
     Exemplary embodiments of each lens elements of the optical imaging lens  1  will now be described with reference to the drawings. Each of the first, second, third, fourth, fifth, and sixth lens elements  110 ,  120 ,  130 ,  140 ,  150 ,  160  has an object-side surface  111 / 121 / 131 / 141 / 151 / 161  facing toward the object side A 1  and an image-side surface  112 / 122 / 132 / 142 / 152 / 162  facing toward the image side A 2 . Both object-side surface  111 / 121 / 131 / 141 / 151 / 161  and image-side surface  112 / 122 / 132 / 142 / 152 / 162  may be aspherical surfaces. 
     An example embodiment of the first lens element  110  has a positive refractive power, which may be constructed by plastic material. The object-side surface  111  comprises a convex portion  1111  in a vicinity of the optical axis, and a convex portion  1112  in a vicinity of a periphery of the first lens element  110 . The image-side surface  112  comprises a concave portion  1121  in a vicinity of the optical axis, and a concave portion  1122  in a vicinity of a periphery of the first lens element  110 . 
     The second lens element  120  has a positive refractive power, which may be constructed by plastic material. The object-side surface  121  comprises a convex portion  1211  in a vicinity of the optical axis, and a convex portion  1212  in a vicinity of a periphery of the second lens element  120 . The image-side surface  122  comprises a convex portion  1221  in a vicinity of the optical axis, and a convex portion  1222  in a vicinity of a periphery of the second lens element  120 . 
     The third lens element  130  has a negative refractive power, which may be constructed by plastic material. The object-side surface  131  comprises a concave portion  1311  in a vicinity of the optical axis, and a concave portion  1312  in a vicinity of a periphery of the third lens element  130 . The image-side surface  132  comprises a concave portion  1321  in a vicinity of the optical axis, and a concave portion  1322  in a vicinity of a periphery of the third lens element  130 . 
     The fourth lens element  140  has a positive refractive power, which may be constructed by plastic material. The object-side surface  141  comprises a concave portion  1411  in a vicinity of the optical axis, and a concave portion  1412  in a vicinity of a periphery of the fourth lens element  140 . The image-side surface  142  comprises a convex portion  1421  in a vicinity of the optical axis, and a convex portion  1422  in a vicinity of a periphery of the fourth lens element  140 . 
     The fifth lens element  150  has a positive refractive power, which may be constructed by plastic material. The object-side surface  151  comprises a concave portion  1511  in a vicinity of the optical axis, and a concave portion  1512  in a vicinity of a periphery of the fifth lens element  150 . The image-side surface  152  comprises a convex portion  1521  in a vicinity of the optical axis, and a convex portion  1522  in a vicinity of a periphery of the fifth lens element  150 . 
     The sixth lens element  160  has a negative refractive power, which may be constructed by plastic material. The object-side surface  161  comprises a concave portion  1611  in a vicinity of the optical axis, and a convex portion  1612  in a vicinity of a periphery of the sixth lens element  160 . The image-side surface  162  comprises a concave portion  1621  in a vicinity of the optical axis, and a convex portion  1622  in a vicinity of a periphery of the sixth lens element  160 . 
     In example embodiments, air gaps exist between the lens elements  110 - 160 , the filtering unit  170 , and the image plane  180  of the image sensor. For example,  FIG.  2    illustrates the air gap d 1  existing between the first lens element  110  and the second lens element  120 , the air gap d 2  existing between the second lens element  120  and the third lens element  130 , the air gap d 3  existing between the third lens element  130  and the fourth lens element  140  the air gap d 4  existing between the fourth lens element  140  and the fifth lens element  150 , the air gap d 5  existing between the fifth lens element  150  and the sixth lens element  160 , the air gap d 6  existing between the sixth lens element  160  and the filtering unit  170 , and the air gap d 7  existing between the filtering unit  170  and the image plane  180  of the image sensor. However, in other embodiments, any of the aforesaid air gaps may or may not exist. For example, the profiles of opposite surfaces of any two adjacent lens elements may correspond to each other, and in such situation, the air gaps may not exist. The air gap d 1  is denoted by G12, the air gap d 2  is denoted by G23, the air gaps d 3  is denoted by G34, the air d 4  gap is denoted by G45, the air gap d 5  is denoted by G56, and the sum of all air gaps d 1 , d 2 , d 3 , d 4 , d 5  between the first though sixth lens elements is denoted by Gaa. 
       FIG.  4    depicts the optical characteristics of each lens elements in the optical imaging lens  1  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=14.748, satisfying Equation (1), and (1′); 
     ALT/G23=53.090, satisfying Equation (2), and (2′); 
     Gaa/T5=2.970, satisfying Equation (3), and (3′); 
     Gaa/T3=5.554, satisfying Equation (4), and (4′); 
     ALT/T6=5.062, satisfying Equation (5), and (5′); 
     TTL/T1=9.181, satisfying Equation (6), and (6′); 
     ALT/G56=33.083; 
     Gaa/T2=1.883, satisfying Equation (8), and (8′); and 
     Gaa/T1=2.711, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  111  of the first lens element  110  to the image plane  180  along the optical axis is 4.514 mm, and the length of the optical imaging lens  1  is indeed shortened. 
     The aspherical surfaces, including the object-side surfaces  111 ,  121 ,  131 ,  141 ,  151 ,  161  and the image-side surfaces  112 ,  122 ,  132 ,  142 ,  152 ,  162  are all defined by the following aspherical formula: 
     
       
         
           
             
               Z 
               ⁡ 
               
                 ( 
                 Y 
                 ) 
               
             
             = 
             
               
                 
                   
                     Y 
                     2 
                   
                   R 
                 
                 / 
                 
                   ( 
                   
                     1 
                     + 
                     
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               1 
                               + 
                               K 
                             
                             ) 
                           
                           ⁢ 
                           
                             
                               Y 
                               2 
                             
                             
                               R 
                               2 
                             
                           
                         
                       
                     
                   
                   ) 
                 
               
               + 
               
                 
                   ∑ 
                   
                     i 
                     = 
                     1 
                   
                   n 
                 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 
                   
                     a 
                     
                       2 
                       ⁢ 
                       i 
                     
                   
                   × 
                   
                     Y 
                     
                       2 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       i 
                     
                   
                 
               
             
           
         
       
     
     R represents the radius of curvature of the surface of the lens element; 
     Z represents the depth of the 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 the perpendicular distance between the point of the aspherical surface and the optical axis; 
     K represents a conic constant; and 
     a 2i  represents an aspherical coefficient of 2i th  order. 
     The values of each aspherical parameter, K, and a 4 -a 16  of each lens element  110 ,  120 ,  130 ,  140  are represented in  FIG.  5   . 
       FIG.  3 ( a )  illustrates the longitudinal spherical aberration of the present embodiment, in which curves of different wavelengths are distributed closely, that means the off-axis light with different height of different wavelengths converge in a vicinity of the imaging point.  FIG.  3 ( a )  shows that the offsets between the off-axis light with different light and the imaging point are controlled to be ±0.1 mm. Therefore, the present embodiment improves the spherical aberration in different wavelengths obviously. Additionally, the distances between the three represented wavelengths are quite close, that means the image positions of the different wavelengths converge with one another, such that the chromatic aberration is improved obviously. 
       FIG.  3 ( b )  illustrates an astigmatism aberration in the sagittal direction of the present embodiment, and  FIG.  3 ( c )  illustrates an astigmatism aberration in the tangential direction of the present embodiment. The focal lengths of the three represented wavelengths in the whole field of view are within ±0.10 mm. Therefore, the optical imaging lens  1  of the present embodiment could eliminate the aberration effectively. Additionally, the distances between the three represented wavelengths are quite close, that means the aberration is improved obviously. 
       FIG.  3 ( d )  illustrates a distortion aberration of the present embodiment. The distortion aberration of the present embodiment is maintained within the range of ±2%, that means the distortion aberration meets the image quality of optical system. Accordingly, the system length of the optical imaging lens  1  is shortened to be 5.00 mm approximately, which could overcome the chromatic aberration and provide better image quality. Therefore, the present embodiment achieves great optical performance and the length of the optical imaging lens  1  is effectively shortened. 
     Reference is now made to  FIGS.  6 - 9   .  FIG.  6    illustrates an example cross-sectional view of an optical imaging lens  2  having six lens elements of the optical imaging lens according to a second example embodiment.  FIG.  7    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  2  according to the second example embodiment.  FIG.  8    shows an example table of optical data of each lens element of the optical imaging lens  2  according to the second example embodiment.  FIG.  9    shows an example table of aspherical data of the optical imaging lens  2  according to the second example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  2 , for example, reference number  231  for labeling the object-side surface of the third lens element  230 , reference number  232  for labeling the image-side surface of the third lens element  230 , etc. 
     As shown in  FIG.  6   , the second embodiment is similar to the first embodiment. The optical imaging lens  2 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  200 , first lens element to sixth lens element  210 - 260 . A filtering unit  270  and an image plane  280  of an image sensor are positioned at the image side A 2  of the optical imaging lens  2 . The arrangement of the convex or concave surface structures, including the object-side surfaces  211 ,  221 ,  231 ,  241 ,  251 ,  261  and image-side surfaces  212 ,  222 ,  232 ,  242 ,  252 ,  262  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  2  is the radius of curvature, the values of the central thicknesses of the lens elements  210 - 260  and the air gaps between the lens elements  210 - 260  are slight different from the values of the optical imaging lens  1 . 
     Please refer to  FIG.  8    for the optical characteristics of each lens elements in the optical imaging lens  2  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=11.927, satisfying Equation (1), and (1′); 
     ALT/G23=30.225, satisfying Equation (2), and (2′); 
     Gaa/T5=3.591, satisfying Equation (3), and (3′); 
     Gaa/T3=6.464, satisfying Equation (4), and (4′); 
     ALT/T6=5.521, satisfying Equation (5), and (5′); 
     TTL/T1=10.498, satisfying Equation (6), and (6′); 
     ALT/G56=20.959, satisfying Equation (7), and (7′); 
     Gaa/T2=2.277, satisfying Equation (8), and (8′); and 
     Gaa/T1=3.628, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  211  of the first lens element  210  to the image plane  280  along the optical axis is 4.490 mm, and the length of the optical imaging lens  2  is indeed shortened. 
     As shown in  FIGS.  7 ( a )- 7 ( d ) , the optical imaging lens  2  of the present embodiment shows great characteristics in longitudinal spherical aberration  7 ( a ), astigmatism in the sagittal direction  7 ( b ), astigmatism in the tangential direction  7 ( c ), and distortion aberration  7 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  2  is effectively shortened. 
     Reference is now made to  FIGS.  10 - 13   .  FIG.  10    illustrates an example cross-sectional view of an optical imaging lens  3  having six lens elements of the optical imaging lens according to a third example embodiment.  FIG.  11    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  3  according to the third example embodiment.  FIG.  12    shows an example table of optical data of each lens element of the optical imaging lens  3  according to the third example embodiment.  FIG.  13    shows an example table of aspherical data of the optical imaging lens  3  according to the third example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  3 , for example, reference number  331  for labeling the object-side surface of the third lens element  330 , reference number  332  for labeling the image-side surface of the third lens element  330 , etc. 
     As shown in  FIG.  10   , the third embodiment is similar to the first embodiment. The optical imaging lens  3 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  300 , first lens element to sixth lens element  310 - 360 . A filtering unit  370  and an image plane  380  of an image sensor are positioned at the image side A 2  of the optical imaging lens  3 . The arrangement of the convex or concave surface structures, including the object-side surfaces  311 ,  321 ,  331 ,  341 ,  351 ,  361  and image-side surfaces  312 ,  322 ,  332 ,  342 ,  352 ,  362  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  3  is the radius of curvature, the values of the central thicknesses of the lens elements  310 - 360  and the air gaps between the lens elements  310 - 360  are slight different from the values of the optical imaging lens  1 . 
     Please refer to  FIG.  12    for the optical characteristics of each lens elements in the optical imaging lens  3  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=14.433, satisfying Equation (1), and (1′); 
     ALT/G23=33.788, satisfying Equation (2), and (2′); 
     Gaa/T5=1.885, satisfying Equation (3), and (3′); 
     Gaa/T3=5.727, satisfying Equation (4), and (4′); 
     ALT/T6=8.463, satisfying Equation (5), and (5′); 
     TTL/T1=9.255, satisfying Equation (6), and (6′); 
     ALT/G56=32.241; 
     Gaa/T2=2.125, satisfying Equation (8), and (8′); and 
     Gaa/T1=2.817, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  311  of the first lens element  310  to the image plane  380  along the optical axis is 4.516 mm, and the length of the optical imaging lens  3  is indeed shortened. 
     As shown in  FIGS.  11 ( a )- 11 ( d ) , the optical imaging lens  3  of the present embodiment shows great characteristics in longitudinal spherical aberration  11 ( a ), astigmatism in the sagittal direction  11 ( b ), astigmatism in the tangential direction  11 ( c ), and distortion aberration  11 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  3  is effectively shortened. 
     Reference is now made to  FIGS.  14 - 17   .  FIG.  14    illustrates an example cross-sectional view of an optical imaging lens  4  having six lens elements of the optical imaging lens according to a fourth example embodiment.  FIG.  15    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  4  according to the fourth example embodiment.  FIG.  16    shows an example table of optical data of each lens element of the optical imaging lens  4  according to the fourth example embodiment.  FIG.  17    shows an example table of aspherical data of the optical imaging lens  4  according to the fourth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  4 , for example, reference number  431  for labeling the object-side surface of the third lens element  430 , reference number  432  for labeling the image-side surface of the third lens element  430 , etc. 
     As shown in  FIG.  14   , the fourth embodiment is similar to the first embodiment. The optical imaging lens  4 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  400 , first lens element to sixth lens element  410 - 460 . A filtering unit  470  and an image plane  480  of an image sensor are positioned at the image side A 2  of the optical imaging lens  4 . The arrangement of the convex or concave surface structures, including the object-side surfaces  411 ,  421 ,  431 ,  441 ,  451  and image-side surfaces  412 ,  422 ,  432 ,  442 ,  452 ,  462  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  4  is the radius of curvature, the values of the central thicknesses of the lens elements  410 - 460  and the air gaps between the lens elements  410 - 460  are slight different from the values of the optical imaging lens  1 . Besides, the sixth lens element  460  is slight different from that in the first embodiment. More specifically, the object-side surface  461  of the sixth lens element  460  has a concave portion  4611  in a vicinity of the axis, a concave portion  4612  in a vicinity of a peripheral of the sixth lens element  460 , and a convex portion  4613  in a vicinity between the optical axis and the peripheral of the sixth lens element  460 . 
     Please refer to  FIG.  16    for the optical characteristics of each lens elements in the optical imaging lens  4  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=46.628; 
     ALT/G23=8.328, satisfying Equation (2), and (2′); 
     Gaa/T5=6.242; 
     Gaa/T3=9.817; 
     ALT/T6=6.598, satisfying Equation (5), and (5′); 
     TTL/T1=10.864, satisfying Equation (6), and (6′); 
     ALT/G56=2.949, satisfying Equation (7), and (7′); 
     Gaa/T2=4.892, satisfying Equation (8), and (8′); and 
     Gaa/T1=5.566. 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  411  of the first lens element  410  to the image plane  480  along the optical axis is 4.599 mm, and the length of the optical imaging lens  4  is indeed shortened. 
     As shown in  FIGS.  15 ( a )- 15 ( d ) , the optical imaging lens  4  of the present embodiment shows great characteristics in longitudinal spherical aberration  15 ( a ), astigmatism in the sagittal direction  15 ( b ), astigmatism in the tangential direction  15 ( c ), and distortion aberration  15 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  4  is effectively shortened. 
     Reference is now made to  FIGS.  18 - 21   .  FIG.  18    illustrates an example cross-sectional view of an optical imaging lens  5  having six lens elements of the optical imaging lens according to a fifth example embodiment.  FIG.  19    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  5  according to the fifth example embodiment.  FIG.  20    shows an example table of optical data of each lens element of the optical imaging lens  5  according to the fifth example embodiment.  FIG.  21    shows an example table of aspherical data of the optical imaging lens  5  according to the fifth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  5 , for example, reference number  531  for labeling the object-side surface of the third lens element  530 , reference number  532  for labeling the image-side surface of the third lens element  530 , etc. 
     As shown in  FIG.  18   , the fifth embodiment is similar to the first embodiment. The optical imaging lens  5 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  500 , first lens element to sixth lens element  510 - 560 . A filtering unit  570  and an image plane  580  of an image sensor are positioned at the image side A 2  of the optical imaging lens  5 . The arrangement of the convex or concave surface structures, including the object-side surfaces  511 ,  521 ,  531 ,  541 ,  551 ,  561  and image-side surfaces  512 ,  522 ,  532 ,  542 ,  552 ,  562  are generally same with the optical imaging lens  1 . 
     Please refer to  FIG.  20    for the optical characteristics of each lens elements in the optical imaging lens  5  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=14.964, satisfying Equation (1), and (1′); 
     ALT/G23=30.694, satisfying Equation (2), and (2′); 
     Gaa/T5=2.967, satisfying Equation (3), and (3′); 
     Gaa/T3=6.084, satisfying Equation (4), and (4′); 
     ALT/T6=6.574, satisfying Equation (5), and (5′); 
     TTL/T1=11.080, satisfying Equation (6), and (6′); 
     ALT/G56=29.042, satisfying Equation (7), and (7′); 
     Gaa/T2=2.040, satisfying Equation (8), and (8′); and 
     Gaa/T1=3.638, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  511  of the first lens element  510  to the image plane  580  along the optical axis is 4.447 mm, and the length of the optical imaging lens  5  is indeed shortened. 
     As shown in  FIGS.  19 ( a )- 19 ( d ) , the optical imaging lens  5  of the present embodiment shows great characteristics in longitudinal spherical aberration  19 ( a ), astigmatism in the sagittal direction  19 ( b ), astigmatism in the tangential direction  19 ( c ), and distortion aberration  19 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  5  is effectively shortened. 
     Reference is now made to  FIGS.  22 - 25   .  FIG.  22    illustrates an example cross-sectional view of an optical imaging lens  6  having six lens elements of the optical imaging lens according to a sixth example embodiment.  FIG.  23    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  6  according to the sixth example embodiment.  FIG.  24    shows an example table of optical data of each lens element of the optical imaging lens  6  according to the sixth example embodiment.  FIG.  25    shows an example table of aspherical data of the optical imaging lens  6  according to the sixth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  6 , for example, reference number  631  for labeling the object-side surface of the third lens element  630 , reference number  632  for labeling the image-side surface of the third lens element  630 , etc. 
     As shown in  FIG.  22   , the sixth embodiment is similar to the first embodiment. The optical imaging lens  6 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  600 , first lens element to sixth lens element  610 - 660 . A filtering unit  670  and an image plane  680  of an image sensor are positioned at the image side A 2  of the optical imaging lens  6 . The arrangement of the convex or concave surface structures, including the object-side surfaces  611 ,  621 ,  631 ,  641 ,  551 ,  661  and image-side surfaces  612 ,  622 ,  632 ,  642 ,  652 ,  662  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  6  is the radius of curvature, the values of the central thicknesses of the lens elements  610 - 660  and the air gaps between the lens elements  610 - 660  are slight different from the values of the optical imaging lens  1 . 
     Please refer to  FIG.  24    for the optical characteristics of each lens elements in the optical imaging lens  6  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=16.536, satisfying Equation (1), and (1′); 
     ALT/G23=30.807, satisfying Equation (2), and (2′); 
     Gaa/T5=3.424, satisfying Equation (3), and (3′); 
     Gaa/T3=6.134, satisfying Equation (4), and (4′); 
     ALT/T6=5.021, satisfying Equation (5), and (5′); 
     TTL/T1=11.416, satisfying Equation (6), and (6′); 
     ALT/G56=32.652; 
     Gaa/T2=2.110, satisfying Equation (8), and (8′); and 
     Gaa/T1=3.771, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  611  of the first lens element  610  to the image plane  680  along the optical axis is 4.456 mm, and the length of the optical imaging lens  6  is indeed shortened. 
     As shown in  FIGS.  23 ( a )- 23 ( d ) , the optical imaging lens  6  of the present embodiment shows great characteristics in longitudinal spherical aberration  23 ( a ), astigmatism in the sagittal direction  23 ( b ), astigmatism in the tangential direction  23 ( c ), and distortion aberration  23 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  6  is effectively shortened. 
     Reference is now made to  FIGS.  26 - 29   .  FIG.  26    illustrates an example cross-sectional view of an optical imaging lens  7  having six lens elements of the optical imaging lens according to a seventh example embodiment.  FIG.  27    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  7  according to the seventh example embodiment.  FIG.  28    shows an example table of optical data of each lens element of the optical imaging lens  7  according to the seventh example embodiment.  FIG.  29    shows an example table of aspherical data of the optical imaging lens  7  according to the seventh example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  7 , for example, reference number  731  for labeling the object-side surface of the third lens element  730 , reference number  732  for labeling the image-side surface of the third lens element  730 , etc. 
     As shown in  FIG.  26   , the seventh embodiment is similar to the first embodiment. The optical imaging lens  7 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  700 , first lens element to sixth lens element  710 - 760 . A filtering unit  770  and an image plane  780  of an image sensor are positioned at the image side A 2  of the optical imaging lens  7 . The arrangement of the convex or concave surface structures, including the object-side surfaces  711 ,  721 ,  731 ,  741 ,  751 ,  761  and image-side surfaces  712 ,  722 ,  732 ,  742 ,  752 ,  762  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  7  is the radius of curvature, the values of the central thicknesses of the lens elements  710 - 760  and the air gaps between the lens elements  710 - 760  are slight different from the values of the optical imaging lens  1 . 
     Please refer to  FIG.  28    for the optical characteristics of each lens elements in the optical imaging lens  7  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=5.448, satisfying Equation (1), and (1′); 
     ALT/G23=13.478, satisfying Equation (2), and (2′); 
     Gaa/T5=3.735, satisfying Equation (3), and (3′); 
     Gaa/T3=7.120; 
     ALT/T6=6.246, satisfying Equation (5), and (5′); 
     TTL/T1=11.874; 
     ALT/G56=15.520, satisfying Equation (7), and (7′); 
     Gaa/T2=2.540, satisfying Equation (8), and (8′); and 
     Gaa/T1=4.511. 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  711  of the first lens element  710  to the image plane  780  along the optical axis is 4.498 mm, and the length of the optical imaging lens  7  is indeed shortened. 
     As shown in  FIGS.  27 ( a )- 27 ( d ) , the optical imaging lens  7  of the present embodiment shows great characteristics in longitudinal spherical aberration  27 ( a ), astigmatism in the sagittal direction  27 ( b ), astigmatism in the tangential direction  27 ( c ), and distortion aberration  27 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  7  is effectively shortened. 
     Reference is now made to  FIGS.  30 - 33   .  FIG.  30    illustrates an example cross-sectional view of an optical imaging lens  8  having six lens elements of the optical imaging lens according to an eighth example embodiment.  FIG.  31    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  8  according to the eighth example embodiment.  FIG.  32    shows an example table of optical data of each lens element of the optical imaging lens  8  according to the eighth example embodiment.  FIG.  33    shows an example table of aspherical data of the optical imaging lens  8  according to the eighth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  8 , for example, reference number  831  for labeling the object-side surface of the third lens element  830 , reference number  832  for labeling the image-side surface of the third lens element  830 , etc. 
     As shown in  FIG.  30   , the eighth embodiment is similar to the first embodiment. The optical imaging lens  8 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  800 , first lens element to sixth lens element  810 - 860 . A filtering unit  870  and an image plane  880  of an image sensor are positioned at the image side A 2  of the optical imaging lens  8 . The arrangement of the convex or concave surface structures, including the object-side surfaces  811 ,  821 ,  831 ,  841 ,  851 ,  861  and image-side surfaces  812 ,  822 ,  832 ,  842 ,  852 ,  862  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  8  is the radius of curvature, the values of the central thicknesses of the lens elements  810 - 860  and the air gaps between the lens elements  810 - 860  are slight different from the values of the optical imaging lens  1 . 
     Please refer to  FIG.  32    for the optical characteristics of each lens elements in the optical imaging lens  8  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=18.353, satisfying Equation (1), and (1′); 
     ALT/G23=28.866, satisfying Equation (2), and (2′); 
     Gaa/T5=3.567, satisfying Equation (3), and (3′); 
     Gaa/T3=6.900; 
     ALT/T6=6.407, satisfying Equation (5), and (5′); 
     TTL/T1=10.900, satisfying Equation (6), and (6′); 
     ALT/G56=8.604, satisfying Equation (7), and (7′); 
     Gaa/T2=2.530, satisfying Equation (8), and (8′); and 
     Gaa/T1=4.511. 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  811  of the first lens element  810  to the image plane  880  along the optical axis is 4.497 mm, and the length of the optical imaging lens  8  is indeed shortened. 
     As shown in  FIGS.  31 ( a )- 31 ( d ) , the optical imaging lens  8  of the present embodiment shows great characteristics in longitudinal spherical aberration  31 ( a ), astigmatism in the sagittal direction  31 ( b ), astigmatism in the tangential direction  31 ( c ), and distortion aberration  31 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  8  is effectively shortened. 
     Reference is now made to  FIGS.  34 - 37   .  FIG.  34    illustrates an example cross-sectional view of an optical imaging lens  9  having six lens elements of the optical imaging lens according to a ninth example embodiment.  FIG.  35    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  9  according to the ninth example embodiment.  FIG.  36    shows an example table of optical data of each lens element of the optical imaging lens  9  according to the ninth example embodiment.  FIG.  37    shows an example table of aspherical data of the optical imaging lens  9  according to the ninth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  9 , for example, reference number  931  for labeling the object-side surface of the third lens element  930 , reference number  932  for labeling the image-side surface of the third lens element  930 , etc. 
     As shown in  FIG.  34   , the ninth embodiment is similar to the first embodiment. The optical imaging lens  9 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  900 , first lens element to sixth lens element  910 - 960 . A filtering unit  970  and an image plane  980  of an image sensor are positioned at the image side A 2  of the optical imaging lens  9 . The arrangement of the convex or concave surface structures, including the object-side surfaces  911 ,  921 ,  931 ,  941 ,  951  and image-side surfaces  912 ,  922 ,  932 ,  942 ,  952 ,  962  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  9  is the radius of curvature, the values of the central thicknesses of the lens elements  910 - 960  and the air gaps between the lens elements  910 - 960  are slight different from the values of the optical imaging lens  1 . Besides, the lens element  960  is slight different from that in the first embodiment. More specifically, the object-side surface  961  of the sixth lens element  960  comprises a convex portion  9611  in a vicinity of the optical axis, a convex portion  9612  in a vicinity of a periphery of the sixth lens element  960 , and a concave portion  9613  in a vicinity between the optical axis and the periphery of the sixth lens element. 
     Please refer to  FIG.  36    for the optical characteristics of each lens elements in the optical imaging lens  9  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=14.706, satisfying Equation (1), and (1′); 
     ALT/G23=32.663, satisfying Equation (2), and (2′); 
     Gaa/T5=3.193, satisfying Equation (3), and (3′); 
     Gaa/T3=5.770, satisfying Equation (4), and (4′); 
     ALT/T6=7.711, satisfying Equation (5), and (5′); 
     TTL/T1=8.768, satisfying Equation (6), and (6′); 
     ALT/G56=24.230, satisfying Equation (7), and (7′); 
     Gaa/T2=1.909, satisfying Equation (8), and (8′); and 
     Gaa/T1=2.730, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  911  of the first lens element  910  to the image plane  980  along the optical axis is 4.540 mm, and the length of the optical imaging lens  9  is indeed shortened. 
     As shown in  FIGS.  35 ( a )- 35 ( d ) , the optical imaging lens  9  of the present embodiment shows great characteristics in longitudinal spherical aberration  35 ( a ), astigmatism in the sagittal direction  35 ( b ), astigmatism in the tangential direction  35 ( c ), and distortion aberration  35 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  9  is effectively shortened. 
     Reference is now made to  FIGS.  38 - 41   .  FIG.  38    illustrates an example cross-sectional view of an optical imaging lens  10  having six lens elements of the optical imaging lens according to a tenth example embodiment.  FIG.  39    shows example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens  10  according to the tenth example embodiment.  FIG.  40    shows an example table of optical data of each lens element of the optical imaging lens  10  according to the tenth example embodiment.  FIG.  41    shows an example table of aspherical data of the optical imaging lens  10  according to the tenth example embodiment. The reference numbers labeled in the present embodiment are similar to those in the first embodiment for the similar elements, but here the reference numbers are initialed with  10 , for example, reference number  1031  for labeling the object-side surface of the third lens element  1030 , reference number  1032  for labeling the image-side surface of the third lens element  1030 , etc. 
     As shown in  FIG.  38   , the tenth embodiment is similar to the first embodiment. The optical imaging lens  10 , in an order from an object side A 1  to an image side A 2 , comprises an aperture stop  1000 , first lens element to sixth lens element  1010 - 1060 . A filtering unit  1070  and an image plane  1080  of an image sensor are positioned at the image side A 2  of the optical imaging lens  10 . The arrangement of the convex or concave surface structures, including the object-side surfaces  1011 ,  1021 ,  1031 ,  1041 ,  1051  and image-side surfaces  1012 ,  1022 ,  1032 ,  1042 ,  1052 ,  1062  are generally same with the optical imaging lens  1 . The difference between the optical imaging lens  1  and the optical imaging lens  10  is the radius of curvature, the values of the central thicknesses of the lens elements  1010 - 1060  and the air gaps between the lens elements  1010 - 1060  are slight different from the values of the optical imaging lens  1 . Besides, the lens element  1060  is slight different from that in the first embodiment. More specifically, the object-side surface  1061  of the sixth lens element  1060  comprises a convex portion  10611  in a vicinity of the optical axis, and a concave portion  10612  in a vicinity of a periphery of the sixth lens element  1060 . 
     Please refer to  FIG.  40    for the optical characteristics of each lens elements in the optical imaging lens  10  and thicknesses of the air gaps of the present embodiment, in which the values of Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 are: 
     Gaa/G45=16.851, satisfying Equation (1), and (1′); 
     ALT/G23=36.654, satisfying Equation (2), and (2′); 
     Gaa/T5=1.199, satisfying Equation (3), and (3′); 
     Gaa/T3=5.122, satisfying Equation (4), and (4′); 
     ALT/T6=7.882, satisfying Equation (5), and (5′); 
     TTL/T1=8.508, satisfying Equation (6), and (6′); 
     ALT/G56=41.114; 
     Gaa/T2=2.273, satisfying Equation (8), and (8′); and 
     Gaa/T1 2.330, satisfying Equation (9), and (9′). 
     The system length of the optical imaging lens, TTL, i.e. the distance from the object-side surface  1011  of the first lens element  1010  to the image plane  1080  along the optical axis is 4.582 mm, and the length of the optical imaging lens  10  is indeed shortened. 
     As shown in  FIGS.  39 ( a )- 39 ( d ) , the optical imaging lens  10  of the present embodiment shows great characteristics in longitudinal spherical aberration  39 ( a ), astigmatism in the sagittal direction  35 ( b ), astigmatism in the tangential direction  39 ( c ), and distortion aberration  39 ( d ). Therefore, according to the above illustration, the optical imaging lens of the present embodiment indeed shows great optical performance and the length of the optical imaging lens  10  is effectively shortened. 
     Please refer to  FIG.  42    which shows the values of TTL, ALT, Gaa, Gaa/G45, ALT/G23, Gaa/T5, Gaa/T3, ALT/T6, ALT/G56, Gaa/T2, TTL/T1, and Gaa/T1 of all ten embodiments, and it is clear that the optical imaging lens of the present invention satisfy the Equations (1) and/or (1′), (2) and/or (2′), (3) and/or (3′), (4) and/or (4′), (5) and/or (5′), (6) and/or (6′), (7) and/or (7′), (8) and/or (8′), or (9) and/or (9′). 
     Please refer to  FIG.  43   , which shows an example structural view of a first embodiment of mobile device  20  applying an aforesaid optical imaging lens. The mobile device  20  comprises a housing  21  and a photography module  22  positioned in the housing  21 . An example of the mobile device  20  may be, but is not limited to, a mobile phone. 
     As shown in  FIG.  43   , the photography module  22  may comprise an aforesaid optical imaging lens, for example the optical imaging lens  1  of the first embodiment, a lens barrel  23  for positioning the optical imaging lens  1 , a module housing unit  24  for positioning the lens barrel  23 , a substrate  182  for positioning the module housing unit  24 , and an image sensor  181  which is positioned at an image side of the optical imaging lens  1 . The image plane  180  is formed on the image sensor  181 . 
     In some other example embodiments, the structure of the filtering unit  170  may be omitted. In some example embodiments, the housing  21 , the lens barrel  23 , and/or the module housing unit  24  may be integrated into a single component or assembled by multiple components. In some example embodiments, the image sensor  181  used in the present embodiment is directly attached to a substrate  182  in the form of a chip on board (COB) package, and such package is different from traditional chip scale packages (CSP) since COB package does not require a cover glass before the image sensor  181  in the optical imaging lens  1 . Aforesaid exemplary embodiments are not limited to this package type and could be selectively incorporated in other described embodiments. 
     The six lens elements  110 ,  120 ,  130 ,  140 ,  150 ,  160  are positioned in the lens barrel  23  in the way of separated by an air gap between any two adjacent lens elements. 
     The module housing unit  24  comprises a seat element  2401  for positioning the lens barrel  23  and an image sensor backseat  2406 , in which the image sensor backseat  2406  is not necessary in other embodiment. The lens barrel  23  and the seat element  2401  are positioned along a same axis I-I′, and the lens barrel  23  is positioned inside the seat element  2401 . 
     Because the length of the optical imaging lens  1  is merely 4.514 (mm), the size of the mobile device  20  may be quite small. Therefore, the embodiments described herein meet the market demand for smaller sized product designs. 
     Reference is now made to  FIG.  44   , which shows another structural view of a second embodiment of mobile device  20 ′ applying the aforesaid optical imaging lens  1 . One difference between the mobile device  20 ′ and the mobile device  20  may be the seat element  2401  further comprises a first lens seat  2402 , a second lens seat  2403 , a coil  2404 , and a magnetic unit  2405 . The first lens seat  2402 , which is close to the outside of the lens barrel  23 , and the lens barrel  23  are positioned along an axis II′. The second lens seat  2403  is positioned along the axis II′ and around the outside of the first lens seat  2402 . The coil  2404  is positioned between the outside of the first lens seat  2402  and the inside of the second lens seat  2403 . The magnetic unit  2405  is positioned between the outside of the coil  2404  and the inside of the second lens seat  2403 . The end facing to the image side of the image sensor backseat  2406  is close to the second lens seat  2403 . 
     The lens barrel  23  and the optical imaging lens  1  positioned therein are driven by the first lens seat  2402  to move along the axis II′. The rest structure of the mobile device  20 ′ is similar to the mobile device  20 . 
     Similarly, because the length of the optical imaging lens 4.514 mm, is shortened, the mobile device  20 ′ may be designed with a smaller size and meanwhile good optical performance is still provided. Therefore, the present embodiment meets the market demand for smaller sized product designs, and maintains good optical characteristics and image quality. Accordingly, the present embodiment not only reduces raw material amount of housing for economic benefits, but also meets smaller sized product design trend and consumer demand. 
     According to above illustration, it is clear that the mobile device and the optical imaging lens thereof in example embodiments, through controlling ratio of at least one central thickness of lens element to a sum of all air gaps along the optical axis between six lens elements in a predetermined range, and incorporated with detail structure and/or reflective power of the lens elements, the length of the optical imaging lens is effectively shortened and meanwhile good optical characters are still provided. 
     While various embodiments in accordance with the disclosed principles have been described above, it should be understood that they have been presented by way of example only, and are not limiting. Thus, the breadth and scope of exemplary embodiment(s) should not be limited by any of the above-described embodiments, but should be defined only in accordance with the claims and their equivalents issuing from this disclosure. Furthermore, the above advantages and features are provided in described embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages. 
     Additionally, the section headings herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of such claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings herein.