Abstract:
Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises five lens elements positioned in an order from an object side to an image side. Through controlling the convex or concave shape of the surfaces of the lens elements to allow the thickness of the second lens element and the sum of all air gaps between all five lens elements along the optical axis satisfying the relation: 0.20&lt;T2&lt;0.50 (mm) and 0.27&lt;(T2/G aa )&lt;0.40, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/289,462, filed on May 28, 2014; which is a continuation of U.S. patent application Ser. No. 13/617,231, filed on Sep. 14, 2012, now U.S. Pat. No. 8,773,767; which claims priority from Taiwan Patent Application No. 101111443, filed on Mar. 30, 2012. The disclosures of which are hereby incorporated by reference in their entirety for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    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 five lens elements and an optical imaging lens thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    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 contained therein. Size reductions may be contributed from various aspects of the mobile devices, which includes 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. 
         [0004]    US Patent Publication No. 20100253829, US Patent Publication No. 2011013069, US Patent Publication No. 20110249346, US Patent Publication No. 20100254029, U.S. Pat. No. 7,826,151, U.S. Pat. No. 7,864,454, U.S. Pat. No. 7,911,711, U.S. Pat. No. 8,072,695, Taiwan Patent No. M368072, Taiwan Patent No. M369460 and Taiwan Patent No. M369459 all disclosed an optical imaging lens constructed with an optical imaging lens having five lens elements. Those disclosed optical imaging lenses involved use of a shortened length of the optical imaging lens; however, some of lengths of the optical imaging lens remained too long. For example, in the first embodiment of Taiwan Patent No. M368072, the length of the optical imaging lens is around 5.61 mm, which is not beneficial for the smaller design of mobile devices. 
         [0005]    How to effectively shorten the lengths of the optical imaging lens is one of the most important topics in the industry to peruse the trend of smaller and smaller mobile devices. Each of the aforesaid patent documents faces the limitation of the size of the mobile device due to the problem of reducing length of the optical imaging lens. Therefore, there is needed to develop optical imaging lens with shorter lengths, while also having good optical characters. 
       SUMMARY OF THE INVENTION 
       [0006]    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 central thickness along the optical axis, and the air gap between two lens elements, etc., the lengths of the optical imaging lens is shortened and meanwhile the good optical characters, such as high resolution and the system performance, are sustained. 
         [0007]    In an exemplary embodiment, an optical imaging lens comprises, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element. The first lens element has positive refractive power and comprises a convex object-side curved surface. The second lens element has negative refractive power and comprises a concave image-side curved surface. The third lens element comprises an object-side curved surface and an image-side curved surface, and the object-side curved surface comprises a concave portion in a vicinity of a periphery of said third lens element and the image-side curved surface comprises a convex portion in a vicinity of a periphery of the third lens element. The fourth lens element comprises a convex image-side curved surface and the fifth lens element comprises an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and the image-side curved surface comprises a concave portion in a vicinity of the optical axis. Lens as a whole has only the five lens elements with refractive power, wherein a central thickness of the second lens element along the optical axis is T2, a sum of all air gaps from the first lens element to the fifth lens element along the optical axis is Gaa, and they satisfy the relation: 
         [0000]      0.20 &lt;T 2&lt;0.50 (mm); and 
         [0000]      0.27&lt;( T 2 /Gaa )&lt;0.40. 
         [0008]    In another exemplary embodiment, other central thickness of lens element along the optical axis and/or other ratio of the central thickness of lens element along the optical axis to the sum of all air gaps could be further controlled, and an example among them is controlling the relation of a central thickness of the third lens element along the optical axis, T3, and the sum of all air gaps from the first lens element to the fifth lens element along the optical axis, Gaa, to satisfy the relation: 
         [0000]      0.30&lt;( T 3 /Gaa )&lt;0.45. 
         [0009]    Another example embodiment comprises controlling T3 to further satisfy the relation: 
         [0000]      0.20 &lt;T 3&lt;0.60 (mm). 
         [0010]    Yet, another example embodiment comprises controlling T2 and Gaa to further satisfy the relation: 
         [0000]      0.21 &lt;T 2&lt;0.47 (mm); and 
         [0000]      0.28&lt;( T 2 /Gaa )&lt;0.40. 
         [0011]    Yet, another example embodiment comprises controlling T3 and Gaa to further satisfy the relation: 
         [0000]      0.25 &lt;T 3&lt;0.57 (mm); and 
         [0000]      0.31&lt;( T 3 /Gaa )&lt;0.45. 
         [0012]    Aforesaid exemplary embodiments are not limited and could be selectively incorporated in other embodiments described herein. 
         [0013]    Lens elements in example embodiments, such as the aforesaid first lens element, second lens element, third lens element, fourth lens element, and fifth lens element, are preferable made by plastic lens element with injection molding. Therefore, the technical barrier and the cost may be affected by the thickness of lens element. For example, if the central thickness of the second lens element along the optical axis, T2, is less than the lower limit, 0.2 (mm), the center of the second lens element may be too thin and cause melting plastic material to fail to pass the mold, and compared with currently technical level, the difficulty and cost for production in such situations are too high. Therefore, the lower limits of the above ranges of T2 and T3 are determined based on currently technical level. Further, the thicknesses of the first lens element, the second lens element, the third lens element, the fourth lens element, and fifth lens element affect the length of the optical imaging lens. For example, if the central thickness of the second lens element along the optical axis, T2, exceeds the upper limit, 0.5 (mm), the second lens element may be too thick and cause the length of the optical imaging lens to be too long and fail to match the request of smaller optical imaging lens. Therefore, the upper limits of above ranges of T2 and T3 are determined based on the preferable length of the optical imaging lens. 
         [0014]    In example embodiments, an aperture stop is provided for adjusting the input of light of the system. For example, the aperture stop is selectively provided but not limited to be positioned at the object side of the first lens element, or positioned between the first lens element and the second lens element. 
         [0015]    In some exemplary embodiments, more details about the convex or concave surface structure and/or the refractive power could be incorporated for one specific lens element or broadly for plural lens elements to enhance the control for the system performance and/or resolution. For example, for the second lens element, an object-side curved surface is comprised, but the object-side curved surface need not be limited to a convex portion in a vicinity of a periphery of the second lens element. An example for illustrating the details broadly for plural lens elements comprises the first lens element having positive refractive power and comprising a convex object-side curved surface; the second lens element having negative refractive power and comprising an object-side curved surface and a concave image-side curved surface; the third lens element comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the third lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the third lens element; the fourth lens element having positive refractive power and comprising a concave object-side curved surface and a convex image-side curved surface; and the fifth lens element having negative refractive power and comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fourth lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fourth lens element. Another example for illustrating the details broadly for plural lens elements comprises the first lens element having positive refractive power and comprising a convex object-side curved surface and a concave image-side curved surface; the second lens element having negative refractive power and comprising an object-side curved surface and a concave image-side curved surface, wherein the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element; the third lens element comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the third lens element, and the image-side curved surface comprises a convex portion in a vicinity of a periphery of the third lens element; the fourth lens element having positive refractive power and comprising a concave object-side curved surface and a convex image-side curved surface; and the fifth lens element having negative refractive power and comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fifth lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fifth lens element. Exemplary embodiments for incorporating details broadly for plural lens elements are not limited to the above examples. 
         [0016]    Further, exemplary embodiments could provide more details about the structure, the refractive power, and/or the aperture stop position for a specific lens element or broadly for plural lens elements to fit variable requests. For example, based on the aforesaid examples, an example embodiment comprises the first lens element comprising a convex image-side curved surface, wherein the object-side curved surface of the second lens element comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided at the object side of the first lens element. Another example embodiment is provided with the first lens element comprising a convex image-side curved surface, wherein the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element, the third lens element having negative refractive power, and an aperture stop provided at the object side of the first lens element. Another example embodiment is provided with the first lens element comprising a concave image-side curved surface, the object-side curved surface of the second lens element comprising a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided between the first lens element and the second lens element. Another example embodiment is provided with the first lens element comprising a concave image-side curved surface, the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided at the object side of the first lens element. Similarly, based on the later of the aforesaid examples, more examples could be obtained with the further details listed below, including an example embodiment is provided with the third lens element having positive refractive power, and the third lens element the image-side curved surface comprising a convex portion in a vicinity of the optical axis. Another example embodiment is provided with the third lens element having negative refractive power, and the image-side curved surface of the third lens element comprising a concave portion in a vicinity of the optical axis. Another example embodiment is provided with the third lens element having negative refractive power, and the image-side curved surface of the third lens element comprising a convex portion in a vicinity of the optical axis. It is noted that the examples above may be incorporated into other embodiments if no inconsistencies arise. 
         [0017]    In another exemplary embodiment, a mobile device comprises a housing and an optical imaging lens assembly positioned in the housing. The optical imaging lens assembly comprises a lens barrel, any of aforesaid example embodiments of optical imaging lens, a module housing unit, and an image sensor. The lens comprising five lens elements with refractive power as a whole is positioned in the lens barrel, the module housing unit is for positioning the optical imaging lens, and the image sensor is positioned at the image-side of the optical imaging lens. 
         [0018]    In exemplary embodiments, the module housing unit comprises, but is not limited to, an image sensor base and an auto focus module, wherein the image sensor base is for fixing the image sensor, and the auto focus module comprises a lens seat for positioning the optical imaging lens to control the focusing of the optical imaging lens. 
         [0019]    Through controlling the ratio of at least one central thickness of lens element along the optical axis to a sum of all air gaps between the five lens elements along the optical axis in a predetermined range, and incorporated with the arrangement of the convex or concave shape of the surfaces of the lens element(s) and/or refraction power, the mobile device and the optical imaging lens thereof in exemplary embodiments achieve good optical characters and effectively shorten the lengths of the optical imaging lens. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Exemplary embodiments will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
           [0021]      FIG. 1  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0022]      FIG. 2  shows another cross-sectional view of a lens element of the optical imaging lens according to an example embodiment; 
           [0023]      FIG. 3  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0024]      FIG. 4  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0025]      FIG. 5A  shows the longitudinal spherical aberration,  FIGS. 5B and 5C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 5D  shows the distortion of the optical imaging lens of  FIG. 1 ; 
           [0026]      FIG. 6  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0027]      FIG. 7  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0028]      FIG. 8  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0029]      FIG. 9A  shows the longitudinal spherical aberration,  FIGS. 9B and 9C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 9D  shows the distortion of the optical imaging lens of  FIG. 6 ; 
           [0030]      FIG. 10  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0031]      FIG. 11  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0032]      FIG. 12  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0033]      FIG. 13A  shows the longitudinal spherical aberration,  FIGS. 13B and 13C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 13D  shows the distortion of the optical imaging lens of  FIG. 10 ; 
           [0034]      FIG. 14  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0035]      FIG. 15  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0036]      FIG. 16  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0037]      FIG. 17A  shows the longitudinal spherical aberration,  FIGS. 17B and 17C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 17D  shows the distortion of the optical imaging lens of  FIG. 14 ; 
           [0038]      FIG. 18  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0039]      FIG. 19  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0040]      FIG. 20  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0041]      FIG. 21A  shows the longitudinal spherical aberration,  FIGS. 21B and 21C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 21D  shows the distortion of the optical imaging lens of  FIG. 18 ; 
           [0042]      FIG. 22  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0043]      FIG. 23  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0044]      FIG. 24  shows a table of aspherical data of the optical imaging lens according to an example embodiment; 
           [0045]      FIG. 25A  shows the longitudinal spherical aberration,  FIGS. 25B and 25C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 25D  shows the distortion of the optical imaging lens of  FIG. 22 ; 
           [0046]      FIG. 26  shows a cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to an example embodiment; 
           [0047]      FIG. 27  shows a table of optical data of each lens element of the optical imaging lens according to an example embodiment; 
           [0048]      FIG. 28  shows a table of aspherical data of the optical imaging lens according to the seventh embodiment of the present invention; 
           [0049]      FIG. 29A  shows the longitudinal spherical aberration,  FIGS. 29B and 29C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 29D  shows the distortion of the optical imaging lens of  FIG. 26 ; 
           [0050]      FIG. 30  shows a comparison table for the values of T2, T3, T2/Gaa and T3/Gaa of example embodiments; 
           [0051]      FIG. 31  shows a structure of an example embodiment of a mobile device; 
           [0052]      FIG. 32  shows an enlarged view of a structure of an example embodiment of a mobile device; and 
           [0053]      FIG. 33  shows another enlarged view of a structure of an example embodiment of a mobile device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0054]    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. 
         [0055]    Example embodiments of an optical imaging lens may comprise a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element. These lens elements may be arranged in an order from an object side to an image side, and example embodiments of the lens as a whole may comprise the five lens elements with refractive power. In an example embodiment: the first lens element having positive refractive power comprises a convex object-side curved surface; the second lens element having negative refractive power comprises a concave image-side curved surface; the third lens element comprises an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a concave portion in a vicinity of a periphery of the third lens element and the image-side curved surface comprises a convex portion in a vicinity of a periphery of the third lens element; the fourth lens element comprises a convex image-side curved surface; the fifth lens element comprises an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis, the image-side curved surface comprises a concave portion in a vicinity of the optical axis. The central thickness of the second lens element the along the optical axis, T2, and the sum of all air gaps between the first lens element to the fifth lens element along the optical axis, Gaa, satisfy the relation as followed: 
         [0000]      0.20 &lt;T 2&lt;0.50 (mm)  equation (1); and
 
         [0000]      0.27&lt;( T 2 /Gaa )&lt;0.40  equation (2);
 
         [0000]      and/or 
         [0000]      0.21 &lt;T 2&lt;0.47 (mm)  equation (1′); and
 
         [0000]      0.28&lt;( T 2 /Gaa )&lt;0.40  equation (2′);
 
         [0056]    to achieve good optical characters and shortened length of the optical imaging lens. 
         [0057]    In some example embodiments, other thicknesses of lens along the optical axis and/or the ratio of which to the sum of all air gaps can be also controlled, and an example is provided with controlling a central thickness of the third lens element along the optical axis, T3, and/or controlling the ratio of T3 to Gaa to satisfy the relation: 
         [0000]      0.20 &lt;T 3&lt;0.60 (mm)  equation (3); and/or
 
         [0000]      0.30&lt;( T 3 /Gaa )&lt;0.45  equation (4);
 
         [0000]      and/or 
         [0000]      0.25 &lt;T 3&lt;0.57 (mm)  equation (3′); and/or
 
         [0000]      0.31&lt;( T 3 /Gaa )&lt;0.45  equation (4′).
 
         [0058]    Because example embodiments of the lens elements, such as aforesaid first lens element, second lens element, third lens element, fourth lens element, and fifth lens element, is preferable a lens elements made by injection-molding plastic, the thickness of the lens elements will affect the technical barrier and cost. For example, if the central thickness of the second lens element along the optical axis, T2, is less than the lower limit, 0.2 (mm), the center of the second lens element may be too thin and cause melting plastic material fail to pass the mold, and compared with currently technical level, the difficulty and cost for production in such situation are too high. It will be appreciated that the lower limits of above ranges of T2 and T3 are determined based on current technical levels. Further, the thicknesses of the first lens element, the second lens element, the third lens element, the fourth lens element, and fifth lens element affect the length of the optical imaging lens. For example, if the central thickness of the second lens element along the optical axis, T2, exceeds the upper limit, 0.5 (mm), the second lens element will be too thick and cause the length of the optical imaging lens to be too long and fail to match the request of a smaller optical imaging lens. Therefore, the upper limits of the above ranges of T2 and T3 are determined based on the preferable length of the optical imaging lens. 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. 
         [0059]    Several exemplary embodiments and associated optical data will now be provided for illustrating example embodiments of optical imaging lens with good optical characters and shortened lengths. Reference is now made to  FIGS. 1-5D .  FIG. 1  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a first example embodiment.  FIG. 2  illustrates another example cross-sectional view of a lens element of the optical imaging lens according to an example embodiment.  FIG. 3  depicts an example table of optical data of each lens element of the optical imaging lens according to an example embodiment.  FIG. 4  depicts an example table of aspherical data of the optical imaging lens according to an example embodiment.  FIGS. 5A-5D  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens according to an example embodiment. 
         [0060]    As shown in  FIG. 1 , the optical imaging lens of the present embodiment comprises, in order from an object side A1 to an image side A2, an aperture stop  100  positioned at the object side of a first lens element  110 , the first lens element  110 , a second lens element  120 , a third lens element  130 , a fourth lens element  140 , and a fifth lens element  150 . Both of a filtering unit  160  and image plane  170  of an image sensor are positioned at the image side A2 of the optical imaging lens. The example embodiment of filtering unit  160  illustrated is an IR cut filter (infrared cut filter) positioned between the image-side curved surface  152  of the fifth lens element  150  and an image plane  170 , which filters out light with specific wavelength from the light passing optical imaging lens. For example, IR light is filtered out, and this will prohibit the IR light which is not seen by human eyes from producing an image on the image plane  170 . 
         [0061]    Exemplary embodiments of each lens elements of the optical imaging lens will now be described with reference to the drawings. 
         [0062]    An example embodiment of the first lens element  110  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  111  and a convex image-side curved surface  112 . The convex surface  111  and convex surface  112  may both be aspherical surfaces. 
         [0063]    The second lens element  120  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  121  having a concave portion  1211  in a vicinity of the optical axis, a concave portion  1212  neighboring the circumference, and a concave image-side curved surface  122 . The curved surface  121  and concave surface  122  may both be aspherical surfaces in a vicinity of the optical axis in a vicinity of the optical axis in a vicinity of a periphery of the fifth lens element  150 . 
         [0064]    The third lens element  130  may have positive refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  131  having a convex 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 , and an image-side curved surface  132 . The image-side curved surface  132  may comprise a concave portion  1321  in a vicinity of the optical axis and a convex portion  1322  in a vicinity of a periphery of the third lens element  130 . The curved surface  131 ,  132  may both be aspherical surfaces. 
         [0065]    The fourth lens element  140  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  141  and a convex image-side curved surface  142 . The concave surface  141  and convex surface  142  may both be aspherical surfaces. 
         [0066]    The fifth lens element  150  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  151 , which may comprise a convex portion  1511  in a vicinity of the optical axis and a convex portion  1512  in a vicinity of a periphery of the fifth lens element  150 , and an image-side curved surface  152 , which may comprise a concave 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 curved surface  151  and the curved surface  152  may both be gull wing surfaces of aspherical surfaces. 
         [0067]    In example embodiments, air gaps exist between the lens elements, the filtering unit  160 , and the image plane  170  of the image sensor. For example,  FIG. 1  illustrates the air gaps d1 existing between the first lens element  110  and the second lens element  120 , the air gaps d2 existing between the second lens element  120  and the third lens element  130 , the air gaps d3 existing between the third lens element  130  and the fourth lens element  140 , the air gaps d4 existing between the fourth lens element  140  and the fifth lens element  150 , the air gaps d5 existing between fifth lens element  150  and the filtering unit  160 , and the air gaps d6 existing between the filtering unit  160  and the image plane  170  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 (attached together and therefore form one surface or do not form a surface at all), and in such situation, the air gaps may not exist. The sum of all air gaps d1, d2, d3, d4 between the first and fifth lens elements is denoted by Gaa. 
         [0068]      FIG. 3  depicts the optical characters of each lens elements in the optical imaging lens of the present embodiment, wherein the values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0069]    T2=0.31000 (mm), satisfying equations (1), (1′); 
         [0070]    T2/Gaa=0.28999, satisfying equations (2), (2′); 
         [0071]    T3=0.34207 (mm), satisfying equations (3), (3′); 
         [0072]    T3/Gaa=0.31999, satisfying equations (4), (4′); 
         [0073]    wherein the distance from the object-side curved surface  111  of the first lens element  110  to the image-side curved surface  152  of the fifth lens element  150  is 3.75436 (mm), and the length of the optical imaging lens is shortened. 
         [0074]    Please note that, in example embodiments, to clearly illustrate the structure of each lens element, only the part where light passes, i.e. effective part, is shown. For example, taking the first lens element  110  as an example,  FIG. 1  illustrates the convex object-side curved surface  111  and the convex image-side curved surface  112 . However, when implementing each lens element of the present embodiment, a non-effective part may be formed selectively. Based on the first lens element  110 , please refer to  FIG. 2 , which illustrates the first lens element  110  comprising a further non-effective part. Here the non-effective part is not limited to a protruding part  113  for mounting the first lens element  110  in the optical imaging lens, and light will not pass through the protruding part  113 . 
         [0075]    As illustrated in  FIG. 1 , the aspherical surfaces, including the convex surface  111  and the convex surface  112  of the first lens element  110 , the curved surface  121  and the concave surface  122  of the second lens element  120 , the curved surfaces  131 ,  132  of the third lens element  130 , the concave surface  141  and the convex surface  142  of the fourth lens element  140 , and the curved surface  151  and the curved surface  152  of fifth lens element  150 , are all defined by the aspherical formula: 
         [0000]    
       
         
           
             
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         [0076]    wherein: 
         [0077]    R represents the radius of the surface of the lens element; 
         [0078]    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); 
         [0079]    Y represents the perpendicular distance between the point of the aspherical surface and the optical axis; 
         [0080]    K represents a conic constant; 
         [0081]    a i  represents an aspherical coefficient of i th  level; 
         [0082]    and the values of each aspherical parameter are represented in  FIG. 4 . 
         [0083]    As illustrated in  FIGS. 5A through 5D , the optical imaging lens of present example embodiments show great characteristics in the longitudinal spherical aberration  FIG. 5A , astigmatism aberration in the sagittal direction  FIG. 5B , astigmatism aberration in the tangential direction  FIG. 5C , and/or distortion aberration  FIG. 5D . Therefore, according to above illustration, the optical imaging lens of example embodiments indeed achieve great optical performance and the length of the optical imaging lens is effectively shortened. 
         [0084]    Reference is now made to  FIGS. 6-9D .  FIG. 6  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a second example embodiment.  FIG. 7  shows an example table of optical data of each lens element of the optical imaging lens according to the second example embodiment.  FIG. 8  shows an example table of aspherical data of the optical imaging lens according to the second example embodiment.  FIG. 9A  shows the longitudinal spherical aberration,  FIGS. 9B and 9C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 9D  show the distortion of the optical imaging lens of  FIG. 6 . 
         [0085]    As shown in  FIG. 6 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises an aperture stop  200  positioned at the object side of a first lens element  210 , the first lens element  210 , a second lens element  220 , a third lens element  230 , a fourth lens element  240 , and a fifth lens element  250 . Both of a filtering unit  260  and an image plane  270  of an image sensor are positioned at the image side A2 of the optical imaging lens. In an example embodiment, filtering unit  260  is an IR cut filter positioned between the image-side curved surface  252  of the fifth lens element  250  and the image plane  270  to filter out light with specific wavelength from the light passing optical imaging lens. For example, IR light is filtered out, and this will prohibit the IR light which is not seen by human eyes from producing an image on image plane  270 . 
         [0086]    One difference between the second embodiments and the first embodiments is that the central thickness of lens T2 of the second lens element  220  and the central thickness of lens T3 of the third lens element  230  are different. In this regard, the sum of all air gaps Gaa from the first lens element  210  to the fifth lens element  250  may be different. Please refer to  FIG. 7  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein the values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0087]    T2=0.25763 (mm), satisfying equations (1), (1′); 
         [0088]    T2/Gaa=0.29805, satisfying equations (2), (2′); 
         [0089]    T3=0.27660 (mm), satisfying equations (3), (3′); 
         [0090]    T3/Gaa=0.32000, satisfying equations (4), (4′) 
         [0091]    wherein the distance from the object side of the first lens element to the image side of the fifth lens element is 3.68615 (mm) and the length of the optical imaging lens is shortened. 
         [0092]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0093]    The first lens element  210  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  211  and a convex image-side curved surface  212 . The convex surface  211  and convex surface  212  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 8  for values of the aspherical parameters. 
         [0094]    The second lens element  220  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  221 , which has a convex portion  2211  in a vicinity of the optical axis and a convex portion  2212  in a vicinity of a periphery of the second lens element  220 , and a concave image-side curved surface  222 . The curved surface  221  and concave surface  222  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 8  for values of the aspherical parameters. 
         [0095]    The third lens element  230  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  231 , which has a convex portion  2311  in a vicinity of the optical axis and a concave portion  2312  in a vicinity of a periphery of the third lens element  230 , and an image-side curved surface  232 , which has a concave portion  2321  in a vicinity of the optical axis and a convex portion  2322  in a vicinity of a periphery of the third lens element  230 . The curved surface  231 ,  232  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 8  for values of the aspherical parameters. 
         [0096]    The fourth lens element  240  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  241  and a convex image-side curved surface  242 . The concave surface  241  and convex surface  242  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 8  for values of the aspherical parameters. 
         [0097]    The fifth lens element  250  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  251 , which has a convex portion  2511  in a vicinity of the optical axis and a convex portion  2512  in a vicinity of a periphery of the fifth lens element  250 , and an image-side curved surface  252 , which has a concave portion  2521  in a vicinity of the optical axis and a convex portion  2522  in a vicinity of a periphery of the fifth lens element  250 . The curved surface  251 ,  252  may both be gull wing surfaces of the aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 8  for values of the aspherical parameters. 
         [0098]    In the present embodiment, similar to the first example embodiment, air gaps may exist between the lens elements  210 ,  220 ,  230 ,  240 ,  250 , the filtering unit  260 , and the image plane  270  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0099]    As shown in  FIGS. 9A through 9D , the optical imaging lens of the present embodiment shows great characteristics in longitudinal spherical aberration  FIG. 9A , astigmatism in the sagittal direction  FIG. 9B , astigmatism in the tangential direction  FIG. 9C , or distortion aberration  FIG. 9D . 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 is effectively shortened. 
         [0100]    Reference is now made to  FIGS. 10-13D .  FIG. 10  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a third example embodiment.  FIG. 11  depicts an example table of optical data of each lens element of the optical imaging lens according to the third example embodiment.  FIG. 12  depicts an example table of aspherical data of the optical imaging lens according to the third example embodiment.  FIGS. 13A through 13D  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens according to the third example embodiment. 
         [0101]    As shown in  FIG. 10 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises a first lens element  310 , an aperture stop  300  positioned between the first lens element  310  and a second lens element  320 , the second lens element  320 , a third lens element  330 , a fourth lens element  340 , and a fifth lens element  350 . Both of a filtering unit  360  and an image plane  370  of an image sensor may be positioned at the image side A2 of the optical imaging lens. Here an example embodiment of the filtering unit  360  is an IR cut filter positioned between the image-side curved surface  352  of the fifth lens element  350  and the image plane  370  to filter out light with specific wavelength from the light passing optical imaging lens. For example, the IR light is filtered out, and this will prohibit the IR light which is not seen by human eyes from producing an image on image plane  370 . 
         [0102]    Please refer to  FIG. 11  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein the values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0103]    T2=0.25285 (mm), satisfying equations (1), (1′); 
         [0104]    T2/Gaa=0.31316, satisfying equations (2), (2′); 
         [0105]    T3=0.27452 (mm), satisfying equations (3), (3′); 
         [0106]    T3/Gaa=0.34000, satisfying equations (4), (4′); 
         [0107]    wherein the distance from the object side of the first lens element  310  to the image side of the fifth lens element  350  is 3.81589 (mm), and the length of the optical imaging lens is shortened. 
         [0108]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0109]    The first lens element  310  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  311  and a concave image-side curved surface  312 . The convex surface  311  and concave surface  312  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 12  for values of the aspherical parameters. 
         [0110]    The aperture stop  300  may be positioned between the first lens element  310  and the second lens element  320 . 
         [0111]    The second lens element  320  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  321 , which has a convex portion  3211  in a vicinity of the optical axis and a convex portion  3212  in a vicinity of a periphery of the second lens element  320 , and a concave image-side curved surface  322 . The curved surface  321  and concave surface  322  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 12  for values of the aspherical parameters. 
         [0112]    The third lens element  330  may have positive refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  331 , which has a convex portion  3311  in a vicinity of the optical axis and a concave portion  3312  in a vicinity of a periphery of the third lens element  330 , and an image-side curved surface  332 , which has a concave portion  3321  in a vicinity of the optical axis and a convex portion  3322  in a vicinity of a periphery of the third lens element  330 . The curved surface  331 ,  332  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 12  for values of the aspherical parameters. 
         [0113]    The fourth lens element  340  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  341  and a convex image-side curved surface  342 . The concave surface  341  and convex surface  342  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 12  for values of the aspherical parameters. 
         [0114]    The fifth lens element  350  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  351 , which has a convex portion  3511  in a vicinity of the optical axis and a convex portion  3512  in a vicinity of a periphery of the fifth lens element  350 , and an image-side curved surface  352 , which has a concave portion  3521  in a vicinity of the optical axis and a convex portion  3522  in a vicinity of a periphery of the fifth lens element  350 . The curved surface  351 ,  352  may both be gull wing surfaces of aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 12  for values of the aspherical parameters. 
         [0115]    In the present embodiment, for comparison, similar to the first embodiment, air gaps may exist between the lens elements  310 ,  320 ,  330 ,  340 ,  350 , the filtering unit  360 , and the image plane  370  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0116]    One difference between the third embodiment and the first embodiment is that the central thickness of lens T2 of the second lens element  320  and the central thickness of lens T3 of the third lens element  330  are different. In this regard, the sum of all air gaps Gaa from the first lens element  310  to the fifth lens element  350  may be different. Further, the aperture stop  300  of the present embodiment may be positioned between the first lens element  310  and the second lens element  320 , which may be different from the position of the aperture stop  100  in front of the first lens element  110  in the first embodiment. 
         [0117]    As illustrated in  FIGS. 13A through 13D , it is clear that the optical imaging lens of the present embodiment may achieve great characteristics in longitudinal spherical aberration  FIG. 13A , astigmatism in the sagittal direction  FIG. 13B , astigmatism in the tangential direction  FIG. 13C , or distortion aberration  FIG. 13D . Therefore, according to above illustration, the optical imaging lens of the present embodiment indeed achieve great optical performance, and the length of the optical imaging lens is effectively shortened. 
         [0118]    Reference is now made to  FIGS. 14-17D .  FIG. 14  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a fourth example embodiment.  FIG. 15  shows an example table of optical data of each lens element of the optical imaging lens according to the fourth example embodiment.  FIG. 16  shows an example table of aspherical data of the optical imaging lens according to the fourth example embodiment.  FIGS. 17A through 17D  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens according to the fourth example embodiment. 
         [0119]    As shown in  FIG. 14 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises an aperture stop  400  positioned at the object side of a first lens element  410 , the first lens element  410 , a second lens element  420 , a third lens element  430 , a fourth lens element  440 , and a fifth lens element  450 . Both of a filtering unit  460  and an image plane  470  of an image sensor may be positioned at the image side A2 of the optical imaging lens. Here an example embodiment of filtering unit  460  is an IR cut filter, which may be positioned between the image-side curved surface  452  of the fifth lens element  450  and the image plane  470  to filter out light with specific wavelength from the light passing optical imaging lens. For example, IR light may be filtered out, and this will prohibit the IR light which is not seen by human eyes from producing an image on image plane  470 . 
         [0120]    Please refer to  FIG. 15  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein The values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0121]    T2=0.45000 (mm), satisfying equations (1), (1′); 
         [0122]    T2/Gaa=0.39001, satisfying equations (2), (2′); 
         [0123]    T3=0.36920 (mm), satisfying equations (3), (3′); 
         [0124]    T3/Gaa=0.31998, satisfying equations (4), (4′); 
         [0125]    wherein the distance from the object side of the first lens element to the image side of the fifth lens element is 3.71940 (mm), and the length of the optical imaging lens is shortened. 
         [0126]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0127]    The first lens element  410  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  411  and a concave image-side curved surface  412 . The convex surface  411  and the concave surface  412  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 16  for values of the aspherical parameters. 
         [0128]    The second lens element  420  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  421 , which has a convex portion  4211  in a vicinity of the optical axis and a concave portion  4212  in a vicinity of a periphery of the second lens element  420 , and a concave image-side curved surface  422 . The curved surface  421  and concave surface  422  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 16  for values of the aspherical parameters. 
         [0129]    The third lens element  430  may have positive refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  431 , which has a convex portion  4311  in a vicinity of the optical axis and a concave portion  4312  in a vicinity of a periphery of the third lens element  430 , and an image-side curved surface  432 , which has a concave portion  4321  in a vicinity of the optical axis and a convex portion  4322  in a vicinity of a periphery of the third lens element  430 . The curved surface  431 ,  432  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 16  for values of the aspherical parameters. 
         [0130]    The fourth lens element  440  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  441  and a convex image-side curved surface  442 . The concave surface  441  and convex surface  442  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 16  for values of the aspherical parameters. 
         [0131]    The fifth lens element  450  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  451 , which has a convex portion  4511  in a vicinity of the optical axis and a convex portion  4512  in a vicinity of a periphery of the fifth lens element  450 , and an image-side curved surface  452 , which has a concave portion  4521  in a vicinity of the optical axis and a convex portion  4522  in a vicinity of a periphery of the fifth lens element  450 . The curved surface  451 ,  452  may both be gull wing surfaces of aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 16  for values of the aspherical parameters. 
         [0132]    In the present embodiment, for comparison, similar to the first embodiment, air gaps may exist between the lens elements  410 ,  420 ,  430 ,  440 ,  450 , the filtering unit  460 , and the image plane  470  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0133]    One difference between the fourth embodiment and the first embodiment is that the central thickness of lens T2 of the second lens element  420  and the central thickness of lens T3 of the third lens element  430  may be different. In this regard, the sum of all air gaps Gaa from the first lens element  410  to the fifth lens element  450  may be different. 
         [0134]    As illustrated in  FIGS. 17A through 17D , it is clear that the optical imaging lens of the present embodiment may achieve great characteristics in longitudinal spherical aberration  FIG. 17A , astigmatism in the sagittal direction  FIG. 17B , astigmatism in the tangential direction  FIG. 17C , or distortion aberration  FIG. 17D . Therefore, according to above illustration, the optical imaging lens of the present embodiment indeed achieves great optical performance, and the length of the optical imaging lens is effectively shortened. 
         [0135]    Reference is now made to  FIGS. 18-21D .  FIG. 18  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a fifth embodiment.  FIG. 19  shows an example table of optical data of each lens element of the optical imaging lens according to the fifth example embodiment.  FIG. 20  shows an example table of aspherical data of the optical imaging lens according to the fifth example embodiment.  FIGS. 21A through 21D  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens according to the fifth example embodiment. 
         [0136]    As shown in  FIG. 18 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises an aperture stop  500  positioned between the object side and a first lens element  510 , the first lens element  510 , a second lens element  520 , a third lens element  530 , a fourth lens element  540 , and a fifth lens element  550 . Both of a filtering unit  560  and an image plane  570  of an image sensor may be positioned at the image side A2 of the optical imaging lens. Here an example embodiment of filtering unit  560  is an IR cut filter, which may be positioned between the image-side curved surface  552  of the fifth lens element  550  and the image plane  570  to filter out light with specific wavelength from the light passing optical imaging lens. For example, IR light may be filtered out, and this will prohibit the IR light which is not seen by human eyes from producing an image on image plane  570 . 
         [0137]    Please refer to  FIG. 19  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein The values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0138]    T2=0.29660 (mm), satisfying equations (1), (1′); 
         [0139]    T2/Gaa=0.29001, satisfying equations (2), (2′); 
         [0140]    T3=0.45000 (mm), satisfying equations (3), (3′); 
         [0141]    T3/Gaa=0.44001, satisfying equations (4), (4′); 
         [0142]    wherein the distance from the object side of the first lens element to the image side of the fifth lens element is 3.70690 (mm), and the length of the optical imaging lens is shortened. 
         [0143]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0144]    The first lens element  510  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  511  and a concave image-side curved surface  512 . The convex surface  511  and concave surface  512  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 20  for values of the aspherical parameters. 
         [0145]    The second lens element  520  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  521 , which has a convex portion  5211  in a vicinity of the optical axis and a convex portion  5212  in a vicinity of a periphery of the second lens element  520 , and a concave image-side curved surface  522 . The curved surface  521  and concave surface  522  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 20  for values of the aspherical parameters. 
         [0146]    The third lens element  530  may have positive refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  531 , which has a concave portion  5311  in a vicinity of the optical axis and a concave portion  5312  in a vicinity of a periphery of the third lens element  530 , and an image-side curved surface  532 , which has a convex portion  5321  in a vicinity of the optical axis and a convex portion  5322  in a vicinity of a periphery of the third lens element  530 . The curved surface  531 ,  532  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 20  for values of the aspherical parameters. 
         [0147]    The fourth lens element  540  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  541  and a convex image-side curved surface  542 . The concave surface  541  and convex surface  542  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 20  for values of the aspherical parameters. 
         [0148]    The fifth lens element  550  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  551 , which has a convex portion  5511  in a vicinity of the optical axis and a convex portion  5512  in a vicinity of a periphery of the fifth lens element  550 , and an image-side curved surface  552 , which has a concave portion  5521  in a vicinity of the optical axis and a convex portion  5522  in a vicinity of a periphery of the fifth lens element  550 . The curved surfaces  551 ,  552  may both be gull wing surfaces of aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 20  for values of the aspherical parameters. 
         [0149]    In the present embodiment, for comparison, similar to the first embodiment, air gaps may exist between the lens elements  510 ,  520 ,  530 ,  540 ,  550 , the filtering unit  560 , and the image plane  570  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0150]    One difference between the fifth embodiment and the first embodiment is that the central thickness of lens T2 of the second lens element  520  and the central thickness of lens T3 of the third lens element  530  may be different. Therefore, the sum of all air gaps Gaa from the first lens element  510  to the fifth lens element  550  may be different. 
         [0151]    As illustrated in  FIGS. 21A through 21D , it is clear that the optical imaging lens of the present embodiment may show great characteristics in longitudinal spherical aberration  FIG. 21A , astigmatism in the sagittal direction  FIG. 21B , astigmatism in the tangential direction  FIG. 21C , or distortion aberration  FIG. 21D . Therefore, according to above illustration, the optical imaging lens of the present embodiment indeed achieves great optical performance, and the length of the optical imaging lens is effectively shortened. 
         [0152]    Reference is now made to  FIGS. 22-25D .  FIG. 22  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a sixth example embodiment.  FIG. 23  shows an example table of optical data of each lens element of the optical imaging lens according to the sixth example embodiment.  FIG. 24  shows an example table of aspherical data of the optical imaging lens according to the sixth example embodiment.  FIG. 25A  shows the longitudinal spherical aberration,  FIGS. 25B and 25C  show the respective astigmatic field curves in the sagittal and tangential direction, and  FIG. 25D  shows the distortion according to the sixth example embodiment. 
         [0153]    As shown in  FIG. 22 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises an aperture stop  600  positioned between the object side and a first lens element  610 , the first lens element  610 , a second lens element  620 , a third lens element  630 , a fourth lens element  640 , and a fifth lens element  650 . Both of a filtering unit  660  and an image plane  670  of an image sensor may be positioned at the image side A2 of the optical imaging lens. Here an example embodiment of filtering unit  660  may be an IR cut filter, which may be positioned between the image-side curved surface  652  of the fifth lens element  650  and the image plane  670  to filter out light with specific wavelength from the light passing optical imaging lens. For example, IR light may be filtered out, and this may prohibit the IR light which is not seen by human eyes from producing an image on image plane  670 . 
         [0154]    Please refer to  FIG. 23  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein The values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0155]    T2=0.36250 (mm), satisfying equations (1), (1′); 
         [0156]    T2/Gaa=0.29000, satisfying equations (2), (2′); 
         [0157]    T3=0.55000 (mm), satisfying equations (3), (3′); 
         [0158]    T3/Gaa=0.44000, satisfying equations (4), (4′); 
         [0159]    wherein the distance from the object side of the first lens element to the image side of the fifth lens element is 3.84120 (mm), and the length of the optical imaging lens is shortened. 
         [0160]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0161]    The first lens element  610  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  611  and a concave image-side curved surface  612 . The convex surface  611  and  612  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 24  for values of the aspherical parameters. 
         [0162]    The second lens element  620  may have negative refractive power, which may be constructed by plastic material, and may be an object-side curved surface  621 , which has a convex portion  6211  in a vicinity of the optical axis and a convex portion  6212  in a vicinity of a periphery of the second lens element  620 , and a concave image-side curved surface  622 . The curved surface  621  and concave surface  622  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 24  for values of the aspherical parameters. 
         [0163]    The third lens element  630  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  631 , which has a concave portion  6311  in a vicinity of the optical axis and a concave portion  6312  in a vicinity of a periphery of the third lens element  630 , and an image-side curved surface  632 , which has a concave portion  6321  in a vicinity of the optical axis and a convex portion  6322  in a vicinity of a periphery of the third lens element  630 . The curved surface  631 ,  632  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 24  for values of the aspherical parameters. 
         [0164]    The fourth lens element  640  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  641  and a convex image-side curved surface  642 . The concave surface  641  and convex surface  642  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 24  for values of the aspherical parameters. 
         [0165]    The fifth lens element  650  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  651 , which has a convex portion  6511  in a vicinity of the optical axis and a convex portion  6512  in a vicinity of a periphery of the fifth lens element  650 , and an image-side curved surface  652 , which has a concave portion  6521  in a vicinity of the optical axis and a convex portion  6522  in a vicinity of a periphery of the fifth lens element  650 . The curved surface  651 ,  652  may both be gull wing surfaces of aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 24  for values of the aspherical parameters. 
         [0166]    In the present embodiment, for comparison, similar to the first embodiment, air gaps may exist between the lens elements  610 ,  620 ,  630 ,  640 ,  650 , the filtering unit  660 , and the image plane  670  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0167]    One difference between the sixth embodiment and the first embodiment is that the central thickness of lens T2 of the second lens element  620  and the central thickness of lens T3 of the third lens element  630  may be different. In this regard, the sum of all air gaps Gaa from the first lens element  610  to the fifth lens element  650  may be different. 
         [0168]    As illustrated in  FIGS. 25A through 25D , it is clear that the optical imaging lens of the present embodiment may show great characteristics in longitudinal spherical aberration  FIG. 25A , astigmatism in the sagittal direction  FIG. 25B , astigmatism in the tangential direction  FIG. 25C , or distortion aberration  FIG. 25D . Therefore, according to above illustration, the optical imaging lens of the present embodiment indeed achieves great optical performance, and the length of the optical imaging lens is effectively shortened. 
         [0169]    Reference is now made to  FIGS. 26-29D .  FIG. 26  illustrates an example cross-sectional view of an optical imaging lens having five lens elements of the optical imaging lens according to a seventh example embodiment.  FIG. 27  shows an example table of optical data of each lens element of the optical imaging lens according to the seventh example embodiment.  FIG. 28  shows an example table of aspherical data of the optical imaging lens according to the seventh example embodiment.  FIGS. 29A through 29D  show example charts of longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens according to the seventh example embodiment. 
         [0170]    As shown in  FIG. 26 , the optical imaging lens of the present embodiment, in an order from an object side A1 to an image side A2, comprises an aperture stop  700  positioned between the object side and a first lens element  710 , the first lens element  710 , a second lens element  720 , a third lens element  730 , a fourth lens element  740 , and a fifth lens element  750 . Both of a filtering unit  760  and an image plane  770  of an image sensor may be positioned at the image side A2 of the optical imaging lens. Here an example embodiment of filtering unit  760  may comprise an IR cut filter, which is positioned between the image-side curved surface  752  of the fifth lens element  750  and the image plane  770  to filter out light with specific wavelength from the light passing optical imaging lens. For example, IR light is filtered out, and this may prohibit the IR light which is not seen by human eyes from producing an image on image plane  770 . 
         [0171]    Please refer to  FIG. 27  for the optical characteristics of each lens elements in the optical imaging lens of the present embodiment, wherein The values of T2, T3, T2/Gaa and T3/Gaa are: 
         [0172]    T2=0.21999 (mm), satisfying equations (1), (1′); 
         [0173]    T2/Gaa=0.28974, satisfying equations (2), (2′); 
         [0174]    T3=0.26816 (mm), satisfying equations (3), (3′); 
         [0175]    T3/Gaa=0.35319, satisfying equations (4), (4′); 
         [0176]    wherein the distance from the object side of the first lens element to the image side of the fifth lens element is 3.59439 (mm), and the length of the optical imaging lens is shortened. 
         [0177]    Example embodiments of the lens elements of the optical imaging lens may comprise the following example embodiments: 
         [0178]    The first lens element  710  may have positive refractive power, which may be constructed by plastic material, and may comprise a convex object-side curved surface  711  and a concave image-side curved surface  712 . The surfaces  711  and  712  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 28  for values of the aspherical parameters. 
         [0179]    The second lens element  720  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  721 , which has a convex portion  7211  in a vicinity of the optical axis and a convex portion  7212  in a vicinity of a periphery of the second lens element  720 , and a concave image-side curved surface  722 . The curved surface  721  and concave surface  722  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 28  for values of the aspherical parameters. 
         [0180]    The third lens element  730  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  731 , which has a concave portion  7311  in a vicinity of the optical axis and a concave portion  7312  in a vicinity of a periphery of the third lens element  730 , and an image-side curved surface  732 , which has a convex portion  7321  in a vicinity of the optical axis and a convex portion  7322  in a vicinity of a periphery of the third lens element  730 . The curved surfaces  731 ,  732  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 28  for values of the aspherical parameters. 
         [0181]    The fourth lens element  740  may have positive refractive power, which may be constructed by plastic material, and may comprise a concave object-side curved surface  741  and a convex image-side curved surface  742 . The concave surface  741  and convex surface  742  may both be aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 28  for values of the aspherical parameters. 
         [0182]    The fifth lens element  750  may have negative refractive power, which may be constructed by plastic material, and may comprise an object-side curved surface  751 , which has a convex portion  7511  in a vicinity of the optical axis and a convex portion  7512  in a vicinity of a periphery of the fifth lens element  750 , and an image-side curved surface  752 , which has a concave portion  7521  in a vicinity of the optical axis and a convex portion  7522  in a vicinity of a periphery of the fifth lens element  750 . The curved surfaces  751 ,  752  may both be gull wing surfaces of aspherical surfaces defined by the aspherical formula. Please refer to  FIG. 28  for values of the aspherical parameters. 
         [0183]    In the present embodiment, for comparison, similar to the first embodiment, air gaps may exist between the lens elements  710 ,  720 ,  730 ,  740 ,  750 , the filtering unit  760 , and the image plane  770  of the image sensor. Please refer to the positions of the air gaps d1, d2, d3, d4, d5, d6 marked in the first embodiment, wherein the sum of the air gaps d1, d2, d3, d4 is Gaa. 
         [0184]    One difference between the seventh embodiment and the first embodiment is the central thickness of lens T2 of the second lens element  720  and the central thickness of lens T3 of the third lens element  730  may be different. In this regard, the sum of all air gaps Gaa from the first lens element  710  to the fifth lens element  750  may be different. 
         [0185]    As illustrated in  FIGS. 29A through 29D , it is clear that the optical imaging lens of the present embodiment may show great characteristics in longitudinal spherical aberration  FIG. 29A , astigmatism in the sagittal direction  FIG. 29B , astigmatism in the tangential direction  FIG. 29C , or distortion aberration  FIG. 29D . Therefore, according to above illustration, the optical imaging lens of the present embodiment indeed achieves great optical performance, and the length of the optical imaging lens is effectively shortened. 
         [0186]    Please refer to  FIG. 30 , which shows the values of T2, T3, T2/Gaa and T3/Gaa of all seven embodiments. As shown, this table provides a clear illustration that the optical imaging lens of example embodiments indeed satisfies the equations (1), (2), (3), (4), (1′), (2′), (3′), and (4′). 
         [0187]    Reference is now made to  FIGS. 31-32 .  FIG. 31  illustrates an example structural view of an example embodiment of mobile device 1.  FIG. 32  shows an example enlarged view of the example embodiment of mobile device 1 of  FIG. 31 . An example of the mobile device 1 may be a mobile phone, but the type of the mobile device 1 should not be limited to such. As shown, the mobile device 1 may comprise a housing  10  and an optical imaging lens assembly  20  positioned in the housing  10 . The housing  10  protects the optical imaging lens assembly  20  therein, and is not limited to any shape or material. The optical imaging lens assembly  20  may comprise a lens barrel  21 , an optical imaging lens  22 , a module housing unit  23 , and an image sensor  171  which is positioned at an image side of the optical imaging lens  22 . In example embodiments, any optical imaging lens may be used as the optical imaging lens  22 , such as any optical imaging lens disclosed in the aforesaid embodiments or other optical imaging lens according to example embodiments. However, for clearly illustrating the present embodiment, the optical imaging lens of the first embodiment will be used as the optical imaging lens  22 . When using other optical imaging lens  22 , the structure of the filtering unit  160  may be omitted. Furthermore, the housing  10 , the lens barrel  21 , and/or the module housing unit  23  may be integrated into a single component or assembled by multiple components. Furthermore, the image sensor  171  used in the present embodiment is directly attached on the substrate  172  in the form of a chip on board (COB) package, and such package is different from traditional chip scale packages (CSP) since it does not require a cover glass. That is, no cover glass is required before the image sensor  171  in the optical imaging lens  22 . It should be noted, however, that example embodiments are not limited to this package type. The optical imaging lens with refractive power as a whole comprises five lens elements  110 ,  120 ,  130 ,  140 ,  150  positioned in the lens barrel  21 , wherein an air gap may exist between any two adjacent lens elements. The module housing unit  23  is provided for positioning the optical imaging lens  22  thereon, and preferably comprises an image sensor base  233  and an auto focus module  234 . The image sensor base  233  may be fixed on the substrate  172 , and the auto focus module  234  may comprise a lens seat  2341  for positioning the optical imaging lens  22 . The lens seat  2341  may be capable of moving back and forth along the optical axis to control the focusing of the optical imaging lens  22 . For example, according to the distance of the object, the optical imaging lens  22  may be moved back and forth until the image focuses on the image plane  170  of the image sensor  171 . Because the length of the optical imaging lens  22  is merely 3.75436 (mm), the size of the mobile device 1 may be quite small with good optical characters. Therefore, the present embodiment meets the demand of smaller sized product design and the request of the market. 
         [0188]    Reference is now made to  FIG. 33 , which shows a structural view of an example embodiment of mobile device 2. Here the housing is not shown, and only the optical imaging lens assembly  20  is shown. As shown, one difference between the mobile device 2 and the mobile device 1 may be the structure of the module housing unit  24 . The module housing unit  24  may comprise an image sensor base  243  and an auto focus module  244 , which may comprise a voice coil motor (VCM) comprising a lens seat  2441 , a magnet  2442  and a coil  2443 . With the magnetic force produced by the magnet  2442  and the coil  2443 , the VCM may move the lens seat  2441  slightly to move the lens seat  2441  back and forth along an optical axis to focus the optical imaging lens  22 . Because the length of the optical imaging lens  22  may be shortened, the mobile device 2 may be designed with a smaller size and meanwhile good optical performance is still provided. Therefore, the present embodiment meets the demand of small sized product design and the request of the market. 
         [0189]    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 to a sum of all air gaps along the optical axis between five lens elements in a predetermined range, and incorporated with detail structure and/or reflection power of the lens elements, the lengths of the optical imaging lens is effectively shortened and meanwhile good optical characters are still provided. 
         [0190]    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. 
         [0191]    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.