Patent Publication Number: US-2013250441-A1

Title: Imaging lens system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 101109619 filed in Taiwan R.O.C on Mar. 21, 2012, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an imaging lens system, and more particularly, to a compact imaging lens system used in electronic products or an imaging lens system in three-dimensions imaging. 
     2. Description of the Prior Art 
     In recent years, with the popularity of portable electronic products having photographing function, the demand of compact imaging lens system has grown. Generally, the sensor of a general photographing camera is none other than CCD (Charge Coupled Device) or CMOS device (Complementary Metal Oxide Semiconductor device). Furthermore, advances in semiconductor manufacturing technology have allowed the pixel size of sensors to be reduced and therefore lead compact imaging lens systems to higher resolution. In the meantime, the demand for better image quality is also increased. 
     A conventional compact photographing optical lens assembly, in order to reduce manufacturing costs, is usually composed of a two-lens structure, such as a two-lens imaging lens assembly disclosed by U.S. Pat. No. 7,525,741. However, two-lens structure has limited ability in correcting aberrations, which is unable to satisfy the demand of high level imaging modules. On the other hand, utilizing too many lens elements in the assembly will also be difficult for the total track length of the lens assembly to stay compact. 
     To obtain high image quality while maintaining the compact feature of the lens assembly, photographing optical lens assembly with three lens elements proves to be the solution. U.S. Pat. No. 7,564,635 discloses a photographing optical lens assembly with three lens elements. However, three lens elements of the lens assembly are all positive refractive lens elements, which make it difficult to correct the aberration (such as chromatic aberration) in the system and the image quality is compensated. Therefore, a need exists in the art for a photographing optical lens assembly that features high image quality without having a long total track length and applicable in portable electronic products. 
     SUMMARY 
     By the following disclosed arrangement, the imaging lens system of the invention makes the central thickness of the second lens element more favorable for not only the efficient spatial arrangement of the lens assembly but also the simpler individual lens production while assuring suitable thickness of the second lens element, thereby assuring image quality and improving yield rate of the product. 
     The present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system; the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an axial distance between the second lens element and the third lens element is T 23 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 0.65&lt;T 23 /CT 3 &lt;1.80. 
     On the other hand, the present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system; the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an axial distance between the first lens element and the second lens element is T 12 , an axial distance between the second lens element and the third lens element is T 23 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 0.5&lt;T 12 /T 23 &lt;1.55. 
     Furthermore, the present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system; the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an Abbe number of the second lens element is V 2 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 15&lt;V 2 &lt;24.5. 
     In the aforementioned imaging lens system, the first lens element has positive refractive power and thereby can provide the main refractive power that the system needs, which is favorable for reducing the total track length of the imaging lens system. The second lens element has negative refractive power so that the aberration generated by the first lens element having positive refractive power and the chromatic aberration of the system can be favorably corrected. The third lens element has negative refractive power so that the principal point of the optical system can be positioned away from the image plane and thereby reducing the total optical track length of the system for keeping the lens compact 
     In the aforementioned imaging lens system, the second lens element is a meniscus lens element with a concave object-side surface and a convex image-side surface so that the aberration generated by the first lens element and the astigmatism of the system can be corrected favorably. When the third lens element is a meniscus lens element with a convex object-side surface and a concave image-side surface, it facilitates the correction of the astigmatism and high order aberrations of the system. In addition, when at least one inflection is formed on the third lens element, the incident angle of light projecting onto the image sensor from the off-axis field can be effectively reduced so that the sensing efficiency of the image sensor can be improved and the off-axis aberration can be corrected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows an imaging lens system in accordance with a first embodiment of the present disclosure. 
         FIG. 1B  shows the aberration curves of the first embodiment of the present disclosure. 
         FIG. 2A  shows an imaging lens system in accordance with a second embodiment of the present disclosure. 
         FIG. 2B  shows the aberration curves of the second embodiment of the present disclosure. 
         FIG. 3A  shows an imaging lens system in accordance with a third embodiment of the present disclosure. 
         FIG. 3B  shows the aberration curves of the third embodiment of the present disclosure. 
         FIG. 4A  shows an imaging lens system in accordance with a fourth embodiment of the present disclosure. 
         FIG. 4B  shows the aberration curves of the fourth embodiment of the present disclosure. 
         FIG. 5A  shows an imaging lens system in accordance with a fifth embodiment of the present disclosure. 
         FIG. 5B  shows the aberration curves of the fifth embodiment of the present disclosure. 
         FIG. 6A  shows an imaging lens system in accordance with a sixth embodiment of the present disclosure. 
         FIG. 6B  shows the aberration curves of the sixth embodiment of the present disclosure. 
         FIG. 7A  shows an imaging lens system in accordance with a seventh embodiment of the present disclosure. 
         FIG. 7B  shows the aberration curves of the seventh embodiment of the present disclosure. 
         FIG. 8A  shows an imaging lens system in accordance with an eighth embodiment of the present disclosure. 
         FIG. 8B  shows the aberration curves of the eighth embodiment of the present disclosure. 
         FIG. 9A  shows an imaging lens system in accordance with a ninth embodiment of the present disclosure. 
         FIG. 9B  shows the aberration curves of the ninth embodiment of the present disclosure. 
         FIG. 10A  shows an imaging lens system in accordance with an eleventh embodiment of the present disclosure. 
         FIG. 10B  shows the aberration curves of the eleventh embodiment of the present disclosure. 
         FIG. 11A  shows an imaging lens system in accordance with an eleventh embodiment of the present disclosure. 
         FIG. 11B  shows the aberration curves of the eleventh embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element, the second lens element and the third lens element; and the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an axial distance between the second lens element and the third lens element is T 23 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 0.65&lt;T 23 /CT 3 &lt;1.80. 
     When the relations of 0.35&lt;CT 1 /CT 2 &lt;1.00 and 0.35&lt;CT 3 /CT 2 &lt;1.00 are satisfied, the central thickness ratio of the first lens element and the second lens element and the central thickness ratio of the second lens element and the third lens element are more appropriate for not only the efficient spatial arrangement of the lens assembly but also the simpler individual lens production while assuring suitable thickness of the second lens element, thereby assuring image quality and improving yield rate of the product; preferably, the following relations are satisfied: 0.50&lt;CT 1 /CT 2 &lt;0.94 and 0.50&lt;CT 3 /CT 2 &lt;0.94. 
     When the relation of −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0 is satisfied, the spherical aberration of the system can be corrected favorably; preferably, the following relation is satisfied: −2.5&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;−0.5. 
     When the relation of 0.65&lt;T 23 /CT 3 &lt;1.80 is satisfied, the distance on the axis between the second and the third lens elements and the thickness of the third lens element can be effectively controlled, which is not only favorable for more efficiency in space arrangement of lens elements, for keeping the lens system compact. 
     When the greatest central thickness is the second lens element among the three lens elements of the imaging lens system, the thickness of the lens elements of the lens system can be then arranged more appropriately and provided the simpler individual lens production while assuring suitable thickness of the second lens element, and thereby not only improving the moldability and homogeneity of the plastic-injection-molded lenses, but also achieving good image quality of the imaging lens system. 
     In the aforementioned imaging lens system, a focal length of the imaging lens system is f, a focal length of the third lens element is f 3 , and they preferably satisfy the following relation: −0.45&lt;f/f 3 &lt;0. When the above relation is satisfied, the refractive power of the third lens element can be avoided from becoming too large, which can reduce the aberration in the imaging lens system and the sensitivity of the system. 
     In the aforementioned imaging lens system, the system further comprising a stop, an axial distance between the stop and the image-side surface of the third lens element is Sd, an axial distance between the object-side surface of the first lens element and the image-side surface of the third lens element is Td, and they preferably satisfy the following relation: 0.65&lt;Sd/Td&lt;0.90. When the above relation is satisfied, a good balance between telecentricity and wide field of view can be achieved. 
     In the aforementioned imaging lens system, a focal length of the second lens element is f 2 , the focal length of the third lens element is f 3 , and they preferably satisfy the following relation: 0&lt;f 2 /f 3 &lt;0.75. When the above relation is satisfied, the refractive power of the second lens element and the third lens element are more balanced for correcting the aberration and reducing the sensitivity. 
     In the aforementioned imaging lens system, an axial distance between the first lens element and the second lens element is T 12 , an axial distance between the second lens element and the third lens element is T 23 , and they preferably satisfy the following relation: 0.5&lt;T 12 /T 23 &lt;1.55. When the above relation is satisfied, the space between lens elements of the lens system is proper, which is not only favorable for more efficiency in space arrangement of lens elements, for keeping the lens system compact. 
     In the aforementioned imaging lens system, the focal length of the imaging lens system is f, the focal length of the second lens element is f 2 , and they preferably satisfy the following relation: −0.70&lt;f/f 2 &lt;−0.25. When the above relation is satisfied, the refractive power of the second lens element is more appropriate. This feature allows aberrations produced by the first lens element to be corrected favorably while preventing the refractive power of the second lens element from becoming too large, so that the sensitivity of the system can be favorably reduced. 
     In the aforementioned imaging lens system, a curvature radius of the image-side surface of the third lens element is R 6 , the focal length of the imaging lens system is f, and they preferably satisfy the following relation: 0.1&lt;R 6 /f&lt;0.6. When the above relation is satisfied, suitable refractive power can be obtained by the configuration of the curvature radius of the image-side surface of the third lens element, and thereby the aberration of the system can be favorably corrected. 
     In the aforementioned imaging lens system, an Abbe number of the second lens element is V 2 , and it preferably satisfies the following relation: 15&lt;V 2 &lt;24.5. When the above relation is satisfied, the chromatic aberration of the imaging lens system can be favorably corrected. 
     In the aforementioned imaging lens system, the central thickness of the first lens element is CT 1 , the central thickness of the second lens element is CT 2 , the central thickness of the third lens element is CT 3 , and they preferably satisfy the following relation: 0.80 mm&lt;CT 1 +CT 2 +CT 3 &lt;1.85 mm. When the above relation is satisfied, the central thickness sum of the first lens element, the second lens element and the third lens element is more appropriate, thereby facilitating the assembly of the lens elements and the space allocation within the imaging lens system. 
     On the other hand, the present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element, the second lens element and the third lens element; and the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an axial distance between the first lens element and the second lens element is T 12 , an axial distance between the second lens element and the third lens element is T 23 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 0.5&lt;T 12 /T 23 &lt;1.55. 
     When the relations of 0.35&lt;CT 1 /CT 2 &lt;1.00 and 0.35&lt;CT 3 /CT 2 &lt;1.00 are satisfied, the central thickness ratio of the first lens element and the second lens element and the central thickness ratio of the second lens element and the third lens element are more appropriate for not only the efficient spatial arrangement of the lens assembly but also the simpler individual lens production while assuring suitable thickness of the second lens element, thereby assuring image quality and improving yield rate of the product; preferably, the following relation is satisfied: 0.50&lt;CT 1 /CT 2 &lt;0.94. 
     When the relation of −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0 is satisfied, the spherical aberration of the system can be corrected favorably; preferably, the following relation is satisfied: −2.5&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;−0.5. 
     When the relation of 0.5&lt;T 12 /T 23 &lt;1.55 is satisfied, the space between lens elements of the lens system is proper, which is not only favorable for more efficiency in space arrangement of lens elements, for keeping the lens system compact. 
     In the aforementioned imaging lens system, the system further comprising a stop, an axial distance between the stop and the image-side surface of the third lens element is Sd, an axial distance between the object-side surface of the first lens element and the image-side surface of the third lens element is Td, and they preferably satisfy the following relation: 0.65&lt;Sd/Td&lt;0.90. When the above relation is satisfied, a good balance between telecentricity and wide field of view can be achieved. 
     In the aforementioned imaging lens system, a focal length of the second lens element is f 2 , the focal length of the third lens element is f 3 , and they preferably satisfy the following relation: 0&lt;f 2 /f 3 &lt;0.75. When the above relation is satisfied, the refractive power of the second lens element and the third lens element are more balanced for correcting the aberration and reducing the sensitivity. 
     In the aforementioned imaging lens system, a focal length of the imaging lens system is f, the focal length of the second lens element is f 2 , and they preferably satisfy the following relation: −0.70&lt;f/f 2 &lt;−0.25. When the above relation is satisfied, the refractive power of the second lens element is more appropriate. This feature allows aberrations produced by the first lens element to be corrected favorably while preventing the refractive power of the second lens element from becoming too large, so that the sensitivity of the system can be favorably reduced. 
     In the aforementioned imaging lens system, a curvature radius of the image-side surface of the third lens element is R 6 , the focal length of the imaging lens system is f, and they preferably satisfy the following relation: 0.1&lt;R 6 /f&lt;0.6. When the above relation is satisfied, suitable refractive power can be obtained by the configuration of the curvature radius of the image-side surface of the third lens element, and thereby the aberration of the system can be favorably corrected. 
     In the aforementioned imaging lens system, the central thickness of the first lens element is CT 1 , the central thickness of the second lens element is CT 2 , the central thickness of the third lens element is CT 3 , and they preferably satisfy the following relation: 0.80 mm&lt;CT 1 +CT 2 +CT 3 &lt;1.85 mm. When the above relation is satisfied, the central thickness sum of the first lens element, the second lens element and the third lens element is more appropriate, thereby facilitating the assembly of the lens elements and the space allocation within the imaging lens system. 
     Furthermore, the present disclosure provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element, the second lens element and the third lens element; and the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT 1 , a central thickness of the second lens element is CT 2 , a central thickness of the third lens element is CT 3 , a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of the image-side surface of the first lens element is R 2 , an Abbe number of the second lens element is V 2 , and they satisfy the following relations: 0.35&lt;CT 1 /CT 2 &lt;1.00; 0.35&lt;CT 3 /CT 2 &lt;1.00; −3.0&lt;(R 1 +R 2 )/(R 1 −R 2 )&lt;0; and 15&lt;V 2 &lt;24.5. 
     When the relations of 0.35&lt;CT 1 /CT 2 &lt;1.00 and 0.35&lt;CT 3 /CT 2 &lt;1.00 are satisfied, the central thickness ratio of the first lens element and the second lens element and the central thickness ratio of the second lens element and the third lens element are more appropriate for not only the efficient spatial arrangement of the lens assembly but also the simpler individual lens production while assuring suitable thickness of the second lens element, thereby assuring image quality and improving yield rate of the product; preferably, the following relation is satisfied: 0.50&lt;CT 1 /CT 2 &lt;0.94. 
     In the aforementioned imaging lens system, the central thickness of the first lens element is CT 1 , the central thickness of the second lens element is CT 2 , the central thickness of the third lens element is CT 3 , and they preferably satisfy the following relation: 0.80 mm&lt;CT 1 +CT 2 +CT 3 &lt;1.85 mm. When the above relation is satisfied, the central thickness sum of the first lens element, the second lens element and the third lens element is more appropriate, thereby facilitating the assembly of the lens elements and the space allocation within the imaging lens system. 
     In the aforementioned imaging lens system, an axial distance between the first lens element and the second lens element is T 12 , an axial distance between the second lens element and the third lens element is T 23 , and they preferably satisfy the following relation: 0.5&lt;T 12 /T 23 &lt;1.55. When the above relation is satisfied, the space between lens elements of the lens system is proper, which is not only favorable for more efficiency in space arrangement of lens elements, for keeping the lens system compact. 
     In the aforementioned imaging lens system, the lens elements can be made of glass or plastic material. If the lens elements are made of glass, the freedom for distributing the refractive power of the imaging lens system can be increased. If plastic material is adopted to produce the lens elements, the production cost will be reduced effectively. Additionally, the surfaces of the lens elements can be aspheric and easily made into non-spherical profiles, allowing more design parameter freedom which can be used to reduce aberrations and the required number of the lens elements used in an optical system. Consequently, the total track length of the imaging lens system can be effectively reduced. 
     In the present imaging lens system, if a lens element has a convex surface, it means the portion of the surface in proximity to the optical axis is convex; if a lens element has a concave surface, it means the portion of the surface in proximity to the optical axis is concave. 
     In the present imaging lens system, there can be at least one stop, such as an aperture stop, a glare stop, or a field stop. Said glare stop or said field stop can be provided for eliminating stray light and thereby improving image resolution thereof. In addition, in the present imaging lens system, an aperture stop can be configured as a front stop (in front of the first lens element), a middle stop (between the first lens element and an image plane) or in front of the image plane. The allocation of the stop is determined by the preference of the optical designer. 
     Preferred embodiments of the present disclosure will be described in the following paragraphs by referring to the accompanying drawings. 
     Embodiment 1 
       FIG. 1A  shows an imaging lens system in accordance with the first embodiment of the present disclosure, and  FIG. 1B  shows the aberration curves of the first embodiment of the present disclosure. The imaging lens system of the first embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  110  made of plastic with positive refractive power having a convex object-side surface  111  and a concave image-side surface  112 , the object-side and image-side surfaces  111  and  112  thereof being aspheric; 
     a second lens element  120  made of plastic with negative refractive power having a concave object-side surface  121  and a convex image-side surface  122 , the object-side and image-side surfaces  121  and  122  thereof being aspheric; and 
     a third lens element  130  made of plastic with negative refractive power having a convex object-side surface  131  and a concave image-side surface  132 , the object-side and image-side surfaces  131  and  132  thereof being aspheric, and at least one inflection point is formed on the object-side surface  131  and the image-side surface  132  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  110 , the second lens element  120  and the third lens element  130  respectively; and the second lens element  120  has the greatest central thickness among the three lens elements  110 ,  120  and  130 ; 
     wherein an aperture stop  100  is disposed between the first lens element  110  and the second lens element  120 ; 
     the imaging lens system further comprises an IR filter  140  disposed between the image-side surface  132  of the third lens element  130  and an image plane  150 , and the IR filter  140  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the first embodiment is shown in TABLE 1, and the aspheric surface data is shown in TABLE 2, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 (Embodiment 1) 
               
               
                 f = 2.85 mm, Fno = 2.50, HFOV = 31.2 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 1.090 
                 (ASP) 
                 0.427 
                 Plastic 
                 1.544 
                 55.9 
                 2.26 
               
               
                 2 
                   
                 8.361 
                 (ASP) 
                 0.042 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.413 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −1.143 
                 (ASP) 
                 0.566 
                 Plastic 
                 1.634 
                 23.8 
                 −10.75 
               
               
                 5 
                   
                 −1.638 
                 (ASP) 
                 0.431 
                   
                   
                   
                   
               
               
                 6 
                 Lens 3 
                 1.330 
                 (ASP) 
                 0.464 
                 Plastic 
                 1.544 
                 55.9 
                 −23.6 
               
               
                 7 
                   
                 1.057 
                 (ASP) 
                 0.500 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.267 
                   
                   
                   
                   
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 −8.0031E−02 
                   0.0000E+00 
                   7.2447E−01 
                 −3.6823E+00 
                 −7.8188E+00 
                 −5.1165E+00 
               
               
                  A4 = 
                   1.0641E−02 
                 −8.3465E−02 
                 −9.7511E−02 
                 −2.6228E−01 
                 −3.1187E−01 
                 −2.2174E−01 
               
               
                  A6 = 
                 −1.5747E−01 
                   6.9562E−02 
                   1.2697E−01 
                   5.9457E−01 
                   2.1103E−01 
                   1.2520E−01 
               
               
                  A8 = 
                   3.7791E−01 
                 −1.1884E+00 
                   1.8885E+00 
                 −2.0606E−01 
                 −5.9100E−02 
                 −5.5857E−02 
               
               
                 A10 = 
                 −6.4855E−01 
                 −6.2387E−01 
                 −5.7166E+00 
                   1.9165E−01 
                   2.7403E−04 
                   1.1596E−02 
               
               
                 A12 = 
                 −1.4141E+00 
                   3.3805E+00 
                 −2.1631E+00 
                 −2.9121E−01 
                 −2.1912E−03 
                 −2.7258E−04 
               
               
                 A14 = 
                   
                   
                   7.2831E+00 
                   2.3209E−01 
                   1.7612E−03 
                 −3.9578E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles is expressed as follows: 
     
       
         
           
             
               X 
                
               
                 ( 
                 Y 
                 ) 
               
             
             = 
             
               
                 
                   ( 
                   
                     
                       Y 
                       2 
                     
                     / 
                     R 
                   
                   ) 
                 
                 / 
                 
                   ( 
                   
                     1 
                     + 
                     
                       sqrt 
                        
                       
                         ( 
                         
                           1 
                           - 
                           
                             
                               ( 
                               
                                 1 
                                 + 
                                 k 
                               
                               ) 
                             
                             * 
                             
                               
                                 ( 
                                 
                                   Y 
                                   / 
                                   R 
                                 
                                 ) 
                               
                               2 
                             
                           
                         
                         ) 
                       
                     
                   
                   ) 
                 
               
               + 
               
                 
                   ∑ 
                   i 
                 
                  
                 
                     
                 
                  
                 
                   
                     ( 
                     Ai 
                     ) 
                   
                   * 
                   
                     ( 
                     
                       Y 
                       i 
                     
                     ) 
                   
                 
               
             
           
         
       
     
     wherein: 
     X: the distance of a point on the aspheric surface at a distance Y from the optical axis relative to the tangential plane at the aspheric surface vertex; 
     Y: the distance from the point on the aspheric surface to the optical axis; 
     R: curvature radius; 
     k: the conic coefficient; 
     Ai: the aspheric coefficient of order i. 
     In the first embodiment of the present imaging lens system, the focal length of the imaging lens system is f, and it satisfies the following relation: f=2.85 (mm). 
     In the first embodiment of the present imaging lens system, the f-number of the imaging lens system is Fno, and it satisfies the relation: Fno=2.50. 
     In the first embodiment of the present imaging lens system, half of the maximal field of view of the imaging lens system is HFOV, and it satisfies the relation: HFOV=31.2 (degree). 
     In the first embodiment of the present imaging lens system, an Abbe number of the second lens element  120  is V 2 , and it satisfies the relation: V 2 =23.8. 
     In the first embodiment of the present imaging lens system, a central thickness of the first lens element  110  is CT 1 , a central thickness of the second lens element  120  is CT 2 , and they satisfy the relation: CT 1 /CT 2 =0.75. 
     In the first embodiment of the present imaging lens system, a central thickness of the third lens element  130  is CT 3 , the central thickness of the second lens element  120  is CT 2 , and they satisfy the relation: CT 3 /CT 2 =0.82. 
     In the first embodiment of the present imaging lens system, the central thickness of the first lens element  110  is CT 1 , the central thickness of the second lens element  120  is CT 2 , the central thickness of the third lens element  130  is CT 3 , and they satisfy the relation: CT 1 +CT 2 +CT 3 =1.46 (mm). 
     In the first embodiment of the present imaging lens system, an axial distance between the first lens element  110  and the second lens element  120  is T 12 , an axial distance between the second lens element  120  and the third lens element  130  is T 23 , and they satisfy the relation: T 12 /T 23 =1.06. 
     In the first embodiment of the present imaging lens system, the axial distance between the second lens element  120  and the third lens element  130  is T 23 , the central thickness of the third lens element  130  is CT 3 , and they satisfy the relation: T 23 /CT 3 =0.93. 
     In the first embodiment of the present imaging lens system, a curvature radius of the object-side surface  111  of the first lens element  110  is R 1 , a curvature radius of the image-side surface  112  of the first lens element  110  is R 2 , and they satisfy the relation: (R 1 +R 2 )/(R 1 −R 2 )=−1.30. 
     In the first embodiment of the present imaging lens system, a curvature radius of the image-side surface  132  of the third lens element  130  is R 6 , the focal length of the imaging lens system is f, and they satisfy the relation: R 6 /f=0.37. 
     In the first embodiment of the present imaging lens system, the focal length of the imaging lens system is f, a focal length of the second lens  120  element is f 2 , and they satisfy the relation: f/f 2 =−0.27. 
     In the first embodiment of the present imaging lens system, the focal length of the imaging lens system is f, a focal length of the third lens  130  element is f 3 , and they satisfy the relation: f/f 3 =−0.12. 
     In the first embodiment of the present imaging lens system, the focal length of the second lens  120  element is f 2 , the focal length of the third lens  130  element is f 3 , and they satisfy the relation: f 2 /f 3 =0.45. 
     In the first embodiment of the present imaging lens system, an axial distance between the stop  100  and the image-side surface  132  of the third lens element  130  is Sd, an axial distance between the object-side surface  111  of the first lens element  110  and the image-side surface  132  of the third lens element  130  is Td, and they satisfy the relation: Sd/Td=0.80. 
     Embodiment 2 
       FIG. 2A  shows an imaging lens system in accordance with the second embodiment of the present disclosure, and  FIG. 2B  shows the aberration curves of the second embodiment of the present disclosure. The imaging lens system of the second embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  210  made of plastic with positive refractive power having a convex object-side surface  211  and a convex image-side surface  212 , the object-side and image-side surfaces  211  and  212  thereof being aspheric; 
     a second lens element  220  made of plastic with negative refractive power having a concave object-side surface  221  and a convex image-side surface  222 , the object-side and image-side surfaces  221  and  222  thereof being aspheric; and 
     a third lens element  230  made of plastic with negative refractive power having a convex object-side surface  231  and a concave image-side surface  232 , the object-side and image-side surfaces  231  and  232  thereof being aspheric, and at least one inflection point is formed on the object-side surface  231  and the image-side surface  232  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  210 , the second lens element  220  and the third lens element  230  respectively; and the second lens element  220  has the greatest central thickness among the three lens elements  210 ,  220  and  230 ; 
     wherein an aperture stop  200  is disposed between the first lens element  210  and the second lens element  220 ; 
     the imaging lens system further comprises an IR filter  240  disposed between the image-side surface  232  of the third lens element  230  and an image plane  250 , and the IR filter  240  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the second embodiment is shown in TABLE 3, and the aspheric surface data is shown in TABLE 4, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 (Embodiment 2) 
               
               
                 f = 3.22 mm, Fno = 2.40, HFOV = 28.6 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 1.501 
                 (ASP) 
                 0.555 
                 Plastic 
                 1.544 
                 55.9 
                 2.47 
               
               
                 2 
                   
                 −10.979 
                 (ASP) 
                 −0.031 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.478 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −1.299 
                 (ASP) 
                 0.616 
                 Plastic 
                 1.640 
                 23.3 
                 −8.54 
               
               
                 5 
                   
                 −2.020 
                 (ASP) 
                 0.517 
                   
                   
                   
                   
               
               
                 6 
                 Lens 3 
                 1.456 
                 (ASP) 
                 0.527 
                 Plastic 
                 1.535 
                 56.3 
                 −70.71 
               
               
                 7 
                   
                 1.225 
                 (ASP) 
                 0.500 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.446 
                   
                   
                   
                   
               
               
                 10 
                 Image 
                 Plano 
                 — 
                   
                   
                   
                   
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 −1.8825E−01 
                 −6.9293E+00 
                 −2.9444E−01 
                 −1.1502E+01 
                 −4.1874E+00 
                 −3.6626E+00 
               
               
                  A4 = 
                 −3.4158E−02 
                 −1.4540E−01 
                   2.0076E−03  
                 −2.0331E−01 
                 −2.0499E−01 
                 −1.4311E−01 
               
               
                  A6 = 
                 −1.5469E−01 
                   4.6512E−02 
                 −1.4032E−05 
                   4.9560E−01 
                   1.3488E−01 
                   6.0169E−02 
               
               
                  A8 = 
                   2.3163E−01 
                 −5.4690E−01 
                   1.1989E+00 
                 −2.8929E−01 
                 −6.0105E−02 
                 −1.5442E−02 
               
               
                 A10 = 
                 −4.8206E−01 
                   5.2039E−01 
                 −2.9166E+00 
                   1.2067E−01 
                   1.3269E−02 
                 −2.7435E−03 
               
               
                 A12 = 
                   
                   
                   2.7713E+00 
                   1.3781E−01 
                   1.4625E−03 
                   2.0170E−03 
               
               
                 A14 = 
                   
                   
                 −5.3313E−01 
                 −1.1198E−01 
                 −7.7268E−04 
                 −2.3704E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the second embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the second embodiment are listed in the following TABLE 5. 
     
       
         
           
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 Embodiment 2 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 3.22 
               
               
                   
                 Fno 
                 2.40 
               
               
                   
                 HFOV [deg.] 
                 28.6 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.90 
               
               
                   
                 CT3/CT2 
                 0.86 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.70 
               
               
                   
                 T12/T23 
                 0.86 
               
               
                   
                 T23/CT3 
                 0.98 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −0.76 
               
               
                   
                 R6/f 
                 0.38 
               
               
                   
                 f/f2 
                 −0.38 
               
               
                   
                 f/f3 
                 −0.05 
               
               
                   
                 f2/f3 
                 0.12 
               
               
                   
                 SD/TD 
                 0.80 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 3 
       FIG. 3A  shows an imaging lens system in accordance with the third embodiment of the present disclosure, and  FIG. 3B  shows the aberration curves of the third embodiment of the present disclosure. The imaging lens system of the third embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  310  made of plastic with positive refractive power having a convex object-side surface  311  and a concave image-side surface  312 , the object-side and image-side surfaces  311  and  312  thereof being aspheric; 
     a second lens element  320  made of plastic with negative refractive power having a concave object-side surface  321  and a convex image-side surface  322 , the object-side and image-side surfaces  321  and  322  thereof being aspheric; and 
     a third lens element  330  made of plastic with negative refractive power having a convex object-side surface  331  and a concave image-side surface  332 , the object-side and image-side surfaces  331  and  332  thereof being aspheric, and at least one inflection point is formed on the object-side surface  331  and the image-side surface  332  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  310 , the second lens element  320  and the third lens element  330  respectively; and the second lens element  320  has the greatest central thickness among the three lens elements  310 ,  320  and  330 ; 
     wherein an aperture stop  300  is disposed between the first lens element  310  and the second lens element  320 ; 
     the imaging lens system further comprises an IR filter  340  disposed between the image-side surface  332  of the third lens element  330  and an image plane  350 , and the IR filter  340  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the third embodiment is shown in TABLE 6, and the aspheric surface data is shown in TABLE 7, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 (Embodiment 3) 
               
               
                 f = 3.13 mm, Fno = 2.40, HFOV = 29.2 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 1.319 
                 (ASP) 
                 0.532 
                 Plastic 
                 1.544 
                 55.9 
                 2.49 
               
               
                 2 
                   
                 40.000 
                 (ASP) 
                 0.000 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.459 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −1.249 
                 (ASP) 
                 0.574 
                 Plastic 
                 1.640 
                 23.3 
                 −9.91 
               
               
                 5 
                   
                 −1.835 
                 (ASP) 
                 0.487 
                   
                   
                   
                   
               
               
                 6 
                 Lens 3 
                 1.388 
                 (ASP) 
                 0.491 
                 Plastic 
                 1.535 
                 56.3 
                 −88.31 
               
               
                 7 
                   
                 1.182 
                 (ASP) 
                 0.500 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.427 
                   
                   
                   
                   
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 −2.1909E−01 
                   5.0000E+01 
                   1.3265E−01 
                 −6.4148E+00 
                 −5.7788E+00 
                 −4.5007E+00 
               
               
                  A4 = 
                 −9.5164E−03 
                 −1.2096E−01 
                 −4.9637E−02 
                 −2.1854E−01 
                 −2.0436E−01 
                 −1.4367E−01 
               
               
                  A6 = 
                 −1.4330E−01 
                   5.9601E−02  
                   1.3914E−01 
                   5.1289E−01 
                   1.3463E−01 
                   5.8812E−02 
               
               
                  A8 = 
                   3.1678E−01 
                 −7.6228E−01 
                   7.0350E−01 
                 −3.0467E−01 
                 −5.9634E−02 
                 −1.5766E−02 
               
               
                 A10 = 
                 −6.2634E−01 
                   7.3072E−01 
                 −2.0442E+00 
                   1.2823E−01 
                   1.3326E−02 
                 −2.5177E−03 
               
               
                 A12 = 
                   
                   
                   2.0196E+00 
                   2.4972E−01 
                   1.4838E−03 
                   1.8430E−03 
               
               
                 A14 = 
                   
                   
                 −5.3313E−01 
                 −2.0392E−01 
                 −7.9376E−04 
                 −1.8629E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the third embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the third embodiment are listed in the following TABLE 8. 
     
       
         
           
               
             
               
                 TABLE 8 
               
               
                   
               
               
                 Embodiment 3 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 3.13 
               
               
                   
                 Fno 
                 2.40 
               
               
                   
                 HFOV [deg.] 
                 29.2 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.93 
               
               
                   
                 CT3/CT2 
                 0.86 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.60 
               
               
                   
                 T12/T23 
                 0.94 
               
               
                   
                 T23/CT3 
                 0.99 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −1.07 
               
               
                   
                 R6/f 
                 0.38 
               
               
                   
                 f/f2 
                 −0.32 
               
               
                   
                 f/f3 
                 −0.04 
               
               
                   
                 f2/f3 
                 0.11 
               
               
                   
                 SD/TD 
                 0.79 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 4 
       FIG. 4A  shows an imaging lens system in accordance with the fourth embodiment of the present disclosure, and  FIG. 4B  shows the aberration curves of the fourth embodiment of the present disclosure. The imaging lens system of the fourth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  410  made of plastic with positive refractive power having a convex object-side surface  411  and a concave image-side surface  412 , the object-side and image-side surfaces  411  and  412  thereof being aspheric; 
     a second lens element  420  made of plastic with negative refractive power having a concave object-side surface  421  and a convex image-side surface  422 , the object-side and image-side surfaces  421  and  422  thereof being aspheric; and 
     a third lens element  430  made of plastic with negative refractive power having a convex object-side surface  431  and a concave image-side surface  432 , the object-side and image-side surfaces  431  and  432  thereof being aspheric, and at least one inflection point is formed on the object-side surface  431  and the image-side surface  432  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  410 , the second lens element  420  and the third lens element  430  respectively; and the second lens element  420  has the greatest central thickness among the three lens elements  410 ,  420  and  430 ; 
     wherein an aperture stop  400  is disposed between an imaged object and the first lens element  410 ; 
     the imaging lens system further comprises an IR filter  440  disposed between the image-side surface  432  of the third lens element  430  and an image plane  450 , and the IR filter  440  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the fourth embodiment is shown in TABLE 9, and the aspheric surface data is shown in TABLE 10, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 (Embodiment 4) 
               
               
                 f = 3.16 mm, Fno = 2.80, HFOV = 28.9 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 −0.105 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 1.170 
                 (ASP) 
                 0.435 
                 Plastic 
                 1.544 
                 55.9 
                 2.22 
               
               
                 3 
                   
                 30.769 
                 (ASP) 
                 0.435 
               
               
                 4 
                 Lens 2 
                 −1.186 
                 (ASP) 
                 0.566 
                 Plastic 
                 1.650 
                 21.4 
                 −5.76 
               
               
                 5 
                   
                 −2.063 
                 (ASP) 
                 0.508 
               
               
                 6 
                 Lens 3 
                 1.378 
                 (ASP) 
                 0.501 
                 Plastic 
                 1.530 
                 55.8 
                 −48.23 
               
               
                 7 
                   
                 1.143 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.461 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −1.8517E+00 
                 −1.0000E+00 
                 −1.5418E+00 
                 7.7351E−01 
                 −3.8058E+00 
                 −4.2581E+00 
               
               
                 A4 = 
                 9.6082E−02 
                 −1.1647E−01 
                 −1.9539E−01 
                 −8.9776E−02 
                 −3.9833E−01 
                 −2.5586E−01 
               
               
                 A6 = 
                 6.2655E−02 
                 −4.0598E−01 
                 −5.9598E−02 
                 4.2295E−01 
                 2.8295E−01 
                 1.5345E−01 
               
               
                 A8 = 
                 −1.1310E+00 
                 8.5929E−01 
                 2.2186E+00 
                 1.9645E−01 
                 −1.0447E−01 
                 −6.9775E−02 
               
               
                 A10 = 
                 3.0852E+00 
                 −3.4641E+00 
                 −1.0184E+01 
                 −8.1994E−01 
                 −8.3496E−03 
                 1.1522E−02 
               
               
                 A12 = 
                 −5.5378E+00 
                 2.1337E+00 
                 1.6985E+01 
                 9.2953E−01 
                 1.0978E−02 
                 9.7546E−04 
               
               
                 A14 = 
                   
                   
                 −9.8944E+00 
                 −1.9445E−01 
                 1.7882E−04 
                 −6.2546E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the fourth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the fourth embodiment are listed in the following TABLE 11. 
     
       
         
           
               
             
               
                 TABLE 11 
               
               
                   
               
               
                 Embodiment 4 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 3.16 
               
               
                   
                 Fno 
                 2.80 
               
               
                   
                 HFOV [deg.] 
                 28.9 
               
               
                   
                 V2 
                 21.4 
               
               
                   
                 CT1/CT2 
                 0.77 
               
               
                   
                 CT3/CT2 
                 0.89 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.50 
               
               
                   
                 T12/T23 
                 0.86 
               
               
                   
                 T23/CT3 
                 1.01 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −1.08 
               
               
                   
                 R6/f 
                 0.36 
               
               
                   
                 f/f2 
                 −0.55 
               
               
                   
                 f/f3 
                 −0.07 
               
               
                   
                 f2/f3 
                 0.12 
               
               
                   
                 SD/TD 
                 0.96 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 5 
       FIG. 5A  shows an imaging lens system in accordance with the fifth embodiment of the present disclosure, and  FIG. 5B  shows the aberration curves of the fifth embodiment of the present disclosure. The imaging lens system of the fifth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  510  made of glass with positive refractive power having a convex object-side surface  511  and a convex image-side surface  512 , the object-side and image-side surfaces  511  and  512  thereof being aspheric; 
     a second lens element  520  made of plastic with negative refractive power having a concave object-side surface  521  and a convex image-side surface  522 , the object-side and image-side surfaces  521  and  522  thereof being aspheric; and 
     a third lens element  530  made of plastic with negative refractive power having a convex object-side surface  531  and a concave image-side surface  532 , the object-side and image-side surfaces  531  and  532  thereof being aspheric, and at least one inflection point is formed on the object-side surface  531  and the image-side surface  532  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  510 , the second lens element  520  and the third lens element  530  respectively; and the second lens element  520  has the greatest central thickness among the three lens elements  510 ,  520  and  530 ; 
     wherein an aperture stop  500  is disposed between the first lens element  510  and the second lens element  520 ; 
     the imaging lens system further comprises an IR filter  540  disposed between the image-side surface  532  of the third lens element  530  and an image plane  550 , and the IR filter  540  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the fifth embodiment is shown in TABLE 12, and the aspheric surface data is shown in TABLE 13, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 12 
               
             
            
               
                   
               
               
                 (Embodiment 5) 
               
               
                 f = 1.53 mm, Fno = 2.60, HFOV = 30.0 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 0.872 
                 (ASP) 
                 0.325 
                 Glass 
                 1.592 
                 67.0 
                 1.01 
               
               
                 2 
                   
                 −1.655 
                 (ASP) 
                 −0.017 
               
            
           
           
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.207 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −0.586 
                 (ASP) 
                 0.372 
                 Plastic 
                 1.640 
                 23.3 
                 −2.30 
               
               
                 5 
                   
                 −1.214 
                 (ASP) 
                 0.150 
               
               
                 6 
                 Lens 3 
                 0.761 
                 (ASP) 
                 0.304 
                 Plastic 
                 1.530 
                 55.8 
                 −26.64 
               
               
                 7 
                   
                 0.622 
                 (ASP) 
                 0.200 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.203 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −2.1125E+00 
                 −1.0000E+00 
                 −1.4270E+00 
                 7.5067E−01 
                 −1.2447E+01 
                 −5.9798E+00 
               
               
                 A4 = 
                 −3.3376E−01 
                 −1.3472E+00 
                 2.3859E−01 
                 −1.0560E+00 
                 −1.9305E+00 
                 −1.2735E+00 
               
               
                 A6 = 
                 −2.3705E+00 
                 −4.6384E+00 
                 −3.9682E+01 
                 1.9096E+01 
                 3.7774E+00 
                 2.1602E+00 
               
               
                 A8 = 
                 −1.3754E+01 
                 −2.4383E+01 
                 1.2086E+03 
                 −5.9527E+01 
                 −2.2878E+00 
                 −3.6014E+00 
               
               
                 A10 = 
                 −1.3439E+02 
                 2.5725E+02 
                 −1.3376E+04 
                 1.6568E+02 
                 1.3636E+00 
                 2.5473E+00 
               
               
                 A12 = 
                 −3.0564E+02 
                 6.5575E−03 
                 5.0977E+04 
                 4.2868E+01 
                 −1.8737E+01 
                 −9.0509E−02 
               
               
                 A14 = 
                   
                   
                 2.6045E−02 
                 −1.3980E+03 
                 3.1181E+01 
                 −1.2436E+00 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the fifth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the fifth embodiment are listed in the following TABLE 14. 
     
       
         
           
               
             
               
                 TABLE 14 
               
               
                   
               
               
                 Embodiment 5 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 1.53 
               
               
                   
                 Fno 
                 2.60 
               
               
                   
                 HFOV [deg.] 
                 30.0 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.87 
               
               
                   
                 CT3/CT2 
                 0.82 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.00 
               
               
                   
                 T12/T23 
                 1.27 
               
               
                   
                 T23/CT3 
                 0.49 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −0.31 
               
               
                   
                 R6/f 
                 0.41 
               
               
                   
                 f/f2 
                 −0.66 
               
               
                   
                 f/f3 
                 −0.06 
               
               
                   
                 f2/f3 
                 0.09 
               
               
                   
                 SD/TD 
                 0.77 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 6 
       FIG. 6A  shows an imaging lens system in accordance with the sixth embodiment of the present disclosure, and  FIG. 6B  shows the aberration curves of the sixth embodiment of the present disclosure. The imaging lens system of the sixth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  610  made of glass with positive refractive power having a convex object-side surface  611  and a convex image-side surface  612 , the object-side and image-side surfaces  611  and  612  thereof being aspheric; 
     a second lens element  620  made of plastic with negative refractive power having a concave object-side surface  621  and a convex image-side surface  622 , the object-side and image-side surfaces  621  and  622  thereof being aspheric; and 
     a third lens element  630  made of plastic with negative refractive power having a convex object-side surface  631  and a concave image-side surface  632 , the object-side and image-side surfaces  631  and  632  thereof being aspheric, and at least one inflection point is formed on the object-side surface  631  and the image-side surface  632  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  610 , the second lens element  620  and the third lens element  630  respectively; and the second lens element  620  has the greatest central thickness among the three lens elements  610 ,  620  and  630 ; 
     wherein an aperture stop  600  is disposed between the first lens element  610  and the second lens element  620 ; 
     the imaging lens system further comprises an IR filter  640  disposed between the image-side surface  632  of the third lens element  630  and an image plane  650 , and the IR filter  640  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the sixth embodiment is shown in TABLE 15, and the aspheric surface data is shown in TABLE 16, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 15 
               
             
            
               
                   
               
               
                 (Embodiment 6) 
               
               
                 f = 1.89 mm, Fno = 2.60, HFOV = 32.0 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 0.992 
                 (ASP) 
                 0.342 
                 Glass 
                 1.592 
                 67.0 
                 1.31 
               
               
                 2 
                   
                 −3.057 
                 (ASP) 
                 −0.017 
               
            
           
           
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.258 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −0.708 
                 (ASP) 
                 0.386 
                 Plastic 
                 1.640 
                 23.3 
                 −4.41 
               
               
                 5 
                   
                 −1.145 
                 (ASP) 
                 0.288 
               
               
                 6 
                 Lens 3 
                 0.999 
                 (ASP) 
                 0.336 
                 Plastic 
                 1.544 
                 55.9 
                 −8.03 
               
               
                 7 
                   
                 0.717 
                 (ASP) 
                 0.300 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.210 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 16 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −1.9288E+00 
                 −1.0000E+00 
                 −8.7507E−01 
                 −1.6927E+00 
                 −1.4655E+01 
                 −7.0112E+00 
               
               
                 A4 = 
                 −1.2968E−01 
                 −7.3966E−01 
                 −2.6410E−02 
                 −3.1760E−01 
                 −8.5897E−01 
                 −5.7935E−01 
               
               
                 A6 = 
                 −1.2132E+00 
                 −2.1876E+00 
                 −3.3985E+00 
                 5.6920E+00 
                 1.0416E+00 
                 5.8255E−01 
               
               
                 A8 = 
                 −5.7863E−01 
                 −6.9411E+00 
                 1.2063E+02 
                 −7.5732E+00 
                 −2.9820E−01 
                 −5.6258E−01 
               
               
                 A10 = 
                 −4.3581E+01 
                 4.3635E+01 
                 −8.9215E+02 
                 1.0679E+01 
                 −3.0940E−01 
                 2.5940E−01 
               
               
                 A12 = 
                 −1.2927E+01 
                 8.9300E−04 
                 2.1530E+03 
                 −2.8703E+00 
                 −1.2072E+00 
                 −9.9029E−02 
               
               
                 A14 = 
                   
                   
                 2.1197E−03 
                 −3.3283E+01 
                 1.5355E+00 
                 −5.1280E−03 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the sixth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the sixth embodiment are listed in the following TABLE 17. 
     
       
         
           
               
             
               
                 TABLE 17 
               
               
                   
               
               
                 Embodiment 6 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 1.89 
               
               
                   
                 Fno 
                 2.60 
               
               
                   
                 HFOV [deg.] 
                 32.0 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.89 
               
               
                   
                 CT3/CT2 
                 0.87 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.06 
               
               
                   
                 T12/T23 
                 0.84 
               
               
                   
                 T23/CT3 
                 0.86 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −0.51 
               
               
                   
                 R6/f 
                 0.38 
               
               
                   
                 f/f2 
                 −0.43 
               
               
                   
                 f/f3 
                 −0.24 
               
               
                   
                 f2/f3 
                 0.55 
               
               
                   
                 SD/TD 
                 0.80 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 7 
       FIG. 7A  shows an imaging lens system in accordance with the seventh embodiment of the present disclosure, and  FIG. 7B  shows the aberration curves of the seventh embodiment of the present disclosure. The imaging lens system of the seventh embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  710  made of plastic with positive refractive power having a convex object-side surface  711  and a convex image-side surface  712 , the object-side and image-side surfaces  711  and  712  thereof being aspheric; 
     a second lens element  720  made of plastic with negative refractive power having a concave object-side surface  721  and a convex image-side surface  722 , the object-side and image-side surfaces  721  and  722  thereof being aspheric; and 
     a third lens element  730  made of plastic with negative refractive power having a convex object-side surface  731  and a concave image-side surface  732 , the object-side and image-side surfaces  731  and  732  thereof being aspheric, and at least one inflection point is formed on the object-side surface  731  and the image-side surface  732  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  710 , the second lens element  720  and the third lens element  730  respectively; and the second lens element  720  has the greatest central thickness among the three lens elements  710 ,  720  and  730 ; 
     wherein an aperture stop  700  is disposed between the first lens element  710  and the second lens element  720 ; 
     the imaging lens system further comprises an IR filter  740  disposed between the image-side surface  732  of the third lens element  730  and an image plane  750 , and the IR filter  740  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the seventh embodiment is shown in TABLE 18, and the aspheric surface data is shown in TABLE 19, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 18 
               
             
            
               
                   
               
               
                 (Embodiment 7) 
               
               
                 f = 3.21 mm, Fno = 2.40, HFOV = 28.6 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 Lens 1 
                 1.467 
                 (ASP) 
                 0.517 
                 Plastic 
                 1.544 
                 55.9 
                 2.48 
               
               
                 2 
                   
                 −14.756 
                 (ASP) 
                 −0.025 
               
            
           
           
               
               
               
               
               
            
               
                 3 
                 Ape. Stop 
                 Plano 
                 0.488 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 4 
                 Lens 2 
                 −1.395 
                 (ASP) 
                 0.647 
                 Plastic 
                 1.640 
                 23.3 
                 −7.92 
               
               
                 5 
                   
                 −2.273 
                 (ASP) 
                 0.474 
               
               
                 6 
                 Lens 3 
                 1.529 
                 (ASP) 
                 0.593 
                 Plastic 
                 1.535 
                 56.3 
                 −204.73 
               
               
                 7 
                   
                 1.304 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.300 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.416 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 19 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −2.1408E−01 
                 −2.0000E+01 
                 −1.8564E−01 
                 −1.4667E+01 
                 −5.1379E+00 
                 −3.8197E+00 
               
               
                 A4 = 
                 −2.9157E−02 
                 −1.3079E−01 
                 −7.3048E−03 
                 −2.1476E−01 
                 −1.9450E−01 
                 −1.3768E−01 
               
               
                 A6 = 
                 −1.6514E−01 
                 3.7672E−02 
                 2.8153E−02 
                 5.0286E−01 
                 1.2949E−01 
                 5.6260E−02 
               
               
                 A8 = 
                 2.7742E−01 
                 −5.3640E−01 
                 9.2834E−01 
                 −3.1312E−01 
                 −6.1270E−02 
                 −1.3962E−02 
               
               
                 A10 = 
                 −5.6145E−01 
                 4.6400E−01 
                 −2.4148E+00 
                 9.9979E−02 
                 1.4813E−02 
                 −3.3126E−03 
               
               
                 A12 = 
                   
                   
                 2.4232E+00 
                 1.9006E−01 
                 1.9191E−03 
                 2.1738E−03 
               
               
                 A14 = 
                   
                   
                 −5.3313E−01 
                 −1.3261E−01 
                 −1.0531E−03 
                 −2.5159E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the seventh embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the seventh embodiment are listed in the following TABLE 20. 
     
       
         
           
               
             
               
                 TABLE 20 
               
               
                   
               
               
                 Embodiment 7 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 3.21 
               
               
                   
                 Fno 
                 2.40 
               
               
                   
                 HFOV [deg.] 
                 28.6 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.80 
               
               
                   
                 CT3/CT2 
                 0.92 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.76 
               
               
                   
                 T12/T23 
                 0.98 
               
               
                   
                 T23/CT3 
                 0.80 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −0.82 
               
               
                   
                 R6/f 
                 0.41 
               
               
                   
                 f/f2 
                 −0.41 
               
               
                   
                 f/f3 
                 −0.02 
               
               
                   
                 f2/f3 
                 0.04 
               
               
                   
                 SD/TD 
                 0.82 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 8 
       FIG. 8A  shows an imaging lens system in accordance with the eighth embodiment of the present disclosure, and  FIG. 8B  shows the aberration curves of the eighth embodiment of the present disclosure. The imaging lens system of the eighth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  810  made of plastic with positive refractive power having a convex object-side surface  811  and a convex image-side surface  812 , the object-side and image-side surfaces  811  and  812  thereof being aspheric; 
     a second lens element  820  made of plastic with negative refractive power having a concave object-side surface  821  and a convex image-side surface  822 , the object-side and image-side surfaces  821  and  822  thereof being aspheric; and 
     a third lens element  830  made of plastic with negative refractive power having a convex object-side surface  831  and a concave image-side surface  832 , the object-side and image-side surfaces  831  and  832  thereof being aspheric, and at least one inflection point is formed on the object-side surface  831  and the image-side surface  832  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  810 , the second lens element  820  and the third lens element  830  respectively; and the second lens element  820  has the greatest central thickness among the three lens elements  810 ,  820  and  830 ; 
     wherein an aperture stop  800  is disposed between an imaged object and the first lens element  810 ; 
     the imaging lens system further comprises an IR filter  840  disposed between the image-side surface  832  of the third lens element  830  and an image plane  850 , and the IR filter  840  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the eighth embodiment is shown in TABLE 21, and the aspheric surface data is shown in TABLE 22, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 21 
               
             
            
               
                   
               
               
                 (Embodiment 8) 
               
               
                 f = 2.61 mm, Fno = 2.72, HFOV = 33.3 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 −0.093 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 0.987 
                 (ASP) 
                 0.410 
                 Plastic 
                 1.530 
                 55.8 
                 1.85 
               
               
                 3 
                   
                 −100.000 
                 (ASP) 
                 0.322 
               
               
                 4 
                 Lens 2 
                 −0.985 
                 (ASP) 
                 0.496 
                 Plastic 
                 1.650 
                 21.4 
                 −8.16 
               
               
                 5 
                   
                 −1.450 
                 (ASP) 
                 0.477 
               
               
                 6 
                 Lens 3 
                 1.126 
                 (ASP) 
                 0.401 
                 Plastic 
                 1.530 
                 55.8 
                 −6.33 
               
               
                 7 
                   
                 0.739 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.206 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 22 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −1.4900E+00 
                 −1.0000E+00 
                 −3.8768E−01 
                 1.3348E−01 
                 −1.2630E+01 
                 −5.9590E+00 
               
               
                 A4 = 
                 1.1522E−01 
                 −2.3930E−01 
                 −3.3708E−01 
                 −1.1208E−01 
                 −4.6258E−01 
                 −2.9224E−01 
               
               
                 A6 = 
                 −9.0178E−02 
                 −9.0803E−01 
                 1.4159E+00 
                 9.9235E−01 
                 3.04628E−01 
                 2.0636E−01 
               
               
                 A8 = 
                 −2.0128E−01 
                 1.0110E+00 
                 −4.3515E+00 
                 −1.4592E−01 
                 −8.0806E−02 
                 −1.3645E−01 
               
               
                 A10 = 
                 −3.6364E+00 
                 −8.9255E+00 
                 −4.8097E+00 
                 −8.9992E−01 
                 −2.4213E−02 
                 3.6357E−02 
               
               
                 A12 = 
                 −5.3426E+00 
                 2.3413E+00 
                 1.6791E+01 
                 2.7428E+00 
                 7.6497E−03 
                 2.2923E−03 
               
               
                 A14 = 
                   
                   
                 −9.5474E+00 
                 −2.1961E+00 
                 5.0261E−03 
                 −2.8121E−03 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the eighth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the eighth embodiment are listed in the following TABLE 23. 
     
       
         
           
               
             
               
                 TABLE 23 
               
               
                   
               
               
                 Embodiment 8 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 2.61 
               
               
                   
                 Fno 
                 2.72 
               
               
                   
                 HFOV [deg.] 
                 33.3 
               
               
                   
                 V2 
                 21.4 
               
               
                   
                 CT1/CT2 
                 0.83 
               
               
                   
                 CT3/CT2 
                 0.81 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.31 
               
               
                   
                 T12/T23 
                 0.68 
               
               
                   
                 T23/CT3 
                 1.19 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −0.98 
               
               
                   
                 R6/f 
                 0.28 
               
               
                   
                 f/f2 
                 −0.32 
               
               
                   
                 f/f3 
                 −0.41 
               
               
                   
                 f2/f3 
                 1.29 
               
               
                   
                 SD/TD 
                 0.96 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 9 
       FIG. 9A  shows an imaging lens system in accordance with the ninth embodiment of the present disclosure, and  FIG. 9B  shows the aberration curves of the ninth embodiment of the present disclosure. The imaging lens system of the ninth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  910  made of plastic with positive refractive power having a convex object-side surface  911  and a concave image-side surface  912 , the object-side and image-side surfaces  911  and  912  thereof being aspheric; 
     a second lens element  920  made of plastic with negative refractive power having a concave object-side surface  921  and a convex image-side surface  922 , the object-side and image-side surfaces  921  and  922  thereof being aspheric; and 
     a third lens element  930  made of plastic with negative refractive power having a convex object-side surface  931  and a concave image-side surface  932 , the object-side and image-side surfaces  931  and  932  thereof being aspheric, and at least one inflection point is formed on the object-side surface  931  and the image-side surface  932  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  910 , the second lens element  920  and the third lens element  930  respectively; and the second lens element  920  has the greatest central thickness among the three lens elements  910 ,  920  and  930 ; 
     wherein an aperture stop  900  is disposed between an imaged object and the first lens element  910 ; 
     the imaging lens system further comprises an IR filter  940  disposed between the image-side surface  932  of the third lens element  930  and an image plane  950 , and the IR filter  940  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the ninth embodiment is shown in TABLE 24, and the aspheric surface data is shown in TABLE 25, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 24 
               
             
            
               
                   
               
               
                 (Embodiment 9) 
               
               
                 f = 3.16 mm, Fno = 2.80, HFOV = 28.9 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 −0.104 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 1.170 
                 (ASP) 
                 0.467 
                 Plastic 
                 1.544 
                 55.9 
                 2.22 
               
               
                 3 
                   
                 30.769 
                 (ASP) 
                 0.425 
               
               
                 4 
                 Lens 2 
                 −1.149 
                 (ASP) 
                 0.549 
                 Plastic 
                 1.650 
                 21.4 
                 −5.74 
               
               
                 5 
                   
                 −1.974 
                 (ASP) 
                 0.510 
               
               
                 6 
                 Lens 3 
                 1.389 
                 (ASP) 
                 0.503 
                 Plastic 
                 1.530 
                 55.8 
                 −48.11 
               
               
                 7 
                   
                 1.152 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.455 
               
               
                 10 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 25 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 −1.8460E+00 
                 −1.0000E+00 
                 −1.3298E+00 
                 9.2205E−01 
                 −3.6175E+00 
                 −4.3872E+00 
               
               
                 A4 = 
                  9.8716E−02 
                 −1.2242E−01 
                 −1.9827E−01 
                 −8.8045E−02  
                 −4.0544E−01 
                 −2.4812E−01 
               
               
                 A6 = 
                  7.0786E−02 
                 −4.0822E−01 
                 −9.5763E−02 
                 4.1830E−01 
                  2.8734E−01 
                  1.4354E−01 
               
               
                 A8 = 
                 −1.1355E+00 
                  8.7071E−01 
                  2.3661E+00 
                 2.4071E−01 
                 −1.0418E−01 
                 −6.3755E−02 
               
               
                 A10 = 
                  3.1732E+00 
                 −3.5002E+00 
                 −1.0369E+01 
                 −8.4200E−01  
                 −8.8760E−03 
                  1.0584E−02 
               
               
                 A12 = 
                 −5.3578E+00 
                  2.3896E+00 
                  1.6656E+01 
                 9.0885E−01 
                  1.0902E−02 
                  5.3981E−04 
               
               
                 A14 = 
                   
                   
                 −9.4081E+00 
                 −1.6664E−01  
                  2.1158E−04 
                 −4.8292E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the ninth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the ninth embodiment are listed in the following TABLE 26. 
     
       
         
           
               
             
               
                 TABLE 26 
               
               
                   
               
               
                 Embodiment 9 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 3.16 
               
               
                   
                 Fno 
                 2.80 
               
               
                   
                 HFOV [deg.] 
                 28.9 
               
               
                   
                 V2 
                 21.4 
               
               
                   
                 CT1/CT2 
                 0.85 
               
               
                   
                 CT3/CT2 
                 0.92 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.52 
               
               
                   
                 T12/T23 
                 0.83 
               
               
                   
                 T23/CT3 
                 1.01 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −1.08 
               
               
                   
                 R6/f 
                 0.37 
               
               
                   
                 f/f2 
                 −0.55 
               
               
                   
                 f/f3 
                 −0.07 
               
               
                   
                 f2/f3 
                 0.12 
               
               
                   
                 SD/TD 
                 0.96 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 10 
       FIG. 10A  shows an imaging lens system in accordance with the tenth embodiment of the present disclosure, and  FIG. 10B  shows the aberration curves of the tenth embodiment of the present disclosure. The imaging lens system of the tenth embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  1010  made of plastic with positive refractive power having a convex object-side surface  1011  and a concave image-side surface  1012 , the object-side and image-side surfaces  1011  and  1012  thereof being aspheric; 
     a second lens element  1020  made of plastic with negative refractive power having a concave object-side surface  1021  and a convex image-side surface  1022 , the object-side and image-side surfaces  1021  and  1022  thereof being aspheric; and 
     a third lens element  1030  made of plastic with negative refractive power having a convex object-side surface  1031  and a concave image-side surface  1032 , the object-side and image-side surfaces  1031  and  1032  thereof being aspheric, and at least one inflection point is formed on the object-side surface  1031  and the image-side surface  1032  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  1010 , the second lens element  1020  and the third lens element  1030  respectively; and the second lens element  1020  has the greatest central thickness among the three lens elements  1010 ,  1020  and  1030 ; 
     wherein an aperture stop  1000  is disposed between an imaged object and the first lens element  1010 ; 
     the imaging lens system further comprises an IR filter  1040  disposed between the image-side surface  1032  of the third lens element  1030  and an image plane  1050 , and the IR filter  1040  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the tenth embodiment is shown in TABLE 27, and the aspheric surface data is shown in TABLE 28, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 27 
               
             
            
               
                   
               
               
                 (Embodiment 10) 
               
               
                 f = 2.51 mm, Fno = 2.72, HFOV = 34.4 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 −0.092 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 0.968 
                 (ASP) 
                 0.389 
                 Plastic 
                 1.544 
                 55.9 
                 1.83 
               
               
                 3 
                   
                 30.558 
                 (ASP) 
                 0.277 
               
               
                 4 
                 Lens 2 
                 −1.025 
                 (ASP) 
                 0.514 
                 Plastic 
                 1.640 
                 23.3 
                 −5.08 
               
               
                 5 
                   
                 −1.790 
                 (ASP) 
                 0.413 
               
               
                 6 
                 Lens 3 
                 1.083 
                 (ASP) 
                 0.455 
                 Plastic 
                 1.530 
                 55.8 
                 −57.60 
               
               
                 7 
                   
                 0.894 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.200 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.261 
               
               
                 10 
                 Image 
                 Plano 
                 0.000 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 28 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −1.2751E+00 
                 −1.0000E+00 
                 −6.8914E−01 
                 3.0080E−01 
                 −5.7201E+00 
                 −4.5160E+00 
               
               
                 A4 = 
                 1.4135E−01 
                 −1.8418E−01 
                 −2.9820E−01 
                 −1.1140E−01 
                 −3.7950E−01 
                 −2.5761E−01 
               
               
                 A6 = 
                 5.7109E−02 
                 −6.1219E−01 
                 1.3327E+00 
                 9.4231E−01 
                 2.9635E−01 
                 1.5535E−01 
               
               
                 A8 = 
                 −4.0546E−01 
                 −1.1894E−01 
                 −4.1887E+00 
                 5.0448E−02 
                 −9.7440E−02 
                 −7.5035E−02 
               
               
                 A10 = 
                 −3.2133E+00 
                 −1.1526E+01 
                 −1.4291E+01 
                 −1.2902E+00 
                 −1.5874E−02 
                 1.5048E−02 
               
               
                 A12 = 
                 −5.3426E+00 
                 2.3413E+00 
                 1.6791E+01 
                 1.4906E+00 
                 7.6239E−03 
                 −5.4880E−04 
               
               
                 A14 = 
                   
                   
                 −9.5474E+00 
                 −4.0852E−01 
                 1.9822E−03 
                 −6.2454E−04 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the tenth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the tenth embodiment are listed in the following TABLE 29. 
     
       
         
           
               
             
               
                 TABLE 29 
               
               
                   
               
               
                 Embodiment 10 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 2.51 
               
               
                   
                 Fno 
                 2.72 
               
               
                   
                 HFOV [deg.] 
                 34.4 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.76 
               
               
                   
                 CT3/CT2 
                 0.89 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.36 
               
               
                   
                 T12/T23 
                 0.67 
               
               
                   
                 T23/CT3 
                 0.91 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −1.07 
               
               
                   
                 R6/f 
                 0.36 
               
               
                   
                 f/f2 
                 −0.49 
               
               
                   
                 f/f3 
                 −0.04 
               
               
                   
                 f2/f3 
                 0.09 
               
               
                   
                 SD/TD 
                 0.96 
               
               
                   
                   
               
            
           
         
       
     
     Embodiment 11 
       FIG. 11A  shows an imaging lens system in accordance with the eleventh embodiment of the present disclosure, and  FIG. 11B  shows the aberration curves of the eleventh embodiment of the present disclosure. The imaging lens system of the eleventh embodiment of the present disclosure comprises three lens elements, in order from an object side to an image side: 
     a first lens element  1110  made of plastic with positive refractive power having a convex object-side surface  1111  and a concave image-side surface  1112 , the object-side and image-side surfaces  1111  and  1112  thereof being aspheric; 
     a second lens element  1120  made of plastic with negative refractive power having a concave object-side surface  1121  and a convex image-side surface  1122 , the object-side and image-side surfaces  1121  and  1122  thereof being aspheric; and 
     a third lens element  1130  made of plastic with negative refractive power having a convex object-side surface  1131  and a concave image-side surface  1132 , the object-side and image-side surfaces  1131  and  1132  thereof being aspheric, and at least one inflection point is formed on the object-side surface  1131  and the image-side surface  1132  thereof; 
     wherein there are three lens elements with refractive power in the imaging lens system, which are the first lens element  1110 , the second lens element  1120  and the third lens element  1130  respectively; and the second lens element  1120  has the greatest central thickness among the three lens elements  1110 ,  1120  and  1130 ; 
     wherein an aperture stop  1100  is disposed between an imaged object and the first lens element  1110 ; 
     the imaging lens system further comprises an IR filter  1140  disposed between the image-side surface  1132  of the third lens element  1130  and an image plane  1150 , and the IR filter  1140  is made of glass and has no influence on the focal length of the imaging lens system. 
     The detailed optical data of the eleventh embodiment is shown in TABLE 30, and the aspheric surface data is shown in TABLE 31, wherein the units of the curvature radius, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view. 
     
       
         
           
               
             
               
                 TABLE 30 
               
             
            
               
                   
               
               
                 (Embodiment 11) 
               
               
                 f = 1.54 mm, Fno = 2.46, HFOV = 36.4 deg. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                 Focal 
               
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Ape. Stop 
                 Plano 
                 −0.045 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 0.740 
                 (ASP) 
                 0.339 
                 Plastic 
                 1.544 
                 55.9 
                 1.40 
               
               
                 3 
                   
                 23.529 
                 (ASP) 
                 0.241 
               
               
                 4 
                 Lens 2 
                 −0.755 
                 (ASP) 
                 0.363 
                 Plastic 
                 1.640 
                 23.3 
                 −9.04 
               
               
                 5 
                   
                 −1.032 
                 (ASP) 
                 0.183 
               
               
                 6 
                 Lens 3 
                 0.664 
                 (ASP) 
                 0.324 
                 Plastic 
                 1.544 
                 55.9 
                 −59.91 
               
               
                 7 
                   
                 0.539 
                 (ASP) 
                 0.200 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 IR-filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 9 
                   
                 Plano 
                 0.160 
               
               
                 10 
                 Image 
                 Plano 
               
               
                   
               
               
                 * Reference wavelength is d-line 587.6 nm 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 31 
               
             
            
               
                   
               
               
                 Aspheric Coefficients 
               
            
           
           
               
               
            
               
                   
                 Surface # 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 k = 
                 −1.1092E+00 
                 −1.0000E+00 
                 −3.8605E−01 
                 1.2788E+00 
                 −3.7394E+00 
                 −3.0923E+00 
               
               
                 A4 = 
                 1.2654E−01 
                 −7.1739E−01 
                 −5.5079E−01 
                 −1.4519E+00 
                 −2.3553E+00 
                 −1.2931E+00 
               
               
                 A6 = 
                 −5.5814E−01 
                 −4.5742E+00 
                 −2.5688E+01 
                 8.1134E+00 
                 5.6135E+00 
                 2.6392E+00 
               
               
                 A8 = 
                 7.3215E+00 
                 6.2863E+00 
                 2.7819E+02 
                 −2.6388E+01 
                 −8.1451E+00 
                 −3.4433E+00 
               
               
                 A10 = 
                 −1.3923E+02 
                 −2.1386E+02 
                 −1.7984E+03 
                 9.1722E+01 
                 6.6607E+00 
                 4.6098E−01 
               
               
                 A12 = 
                 1.4674E+02 
                 4.7403E+02 
                 4.3152E+03 
                 −9.1281E+01 
                 −2.1925E+00 
                 −1.0981E+00 
               
               
                 A14 = 
                   
                   
                   
                 4.0462E+01 
                   
                 4.1312E−01 
               
               
                   
               
            
           
         
       
     
     The equation of the aspheric surface profiles of the eleventh embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the eleventh embodiment are listed in the following TABLE 32. 
     
       
         
           
               
             
               
                 TABLE 32 
               
               
                   
               
               
                 Embodiment 11 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 f [mm] 
                 1.54 
               
               
                   
                 Fno 
                 2.46 
               
               
                   
                 HFOV [deg.] 
                 36.4 
               
               
                   
                 V2 
                 23.3 
               
               
                   
                 CT1/CT2 
                 0.93 
               
               
                   
                 CT3/CT2 
                 0.89 
               
               
                   
                 CT1 + CT2 + CT3 [mm] 
                 1.03 
               
               
                   
                 T12/T23 
                 1.32 
               
               
                   
                 T23/CT3 
                 0.56 
               
               
                   
                 (R1 + R2)/(R1 − R2) 
                 −1.06 
               
               
                   
                 R6/f 
                 0.35 
               
               
                   
                 f/f2 
                 −0.17 
               
               
                   
                 f/f3 
                 −0.03 
               
               
                   
                 f2/f3 
                 0.15 
               
               
                   
                 SD/TD 
                 0.97 
               
               
                   
                   
               
            
           
         
       
     
     It is to be noted that TABLES 1-32 show different data of the different embodiments, however, the data of the different embodiments are obtained from experiments. Therefore, any imaging lens system of the same structure is considered to be within the scope of the present disclosure even if it uses different data. The embodiments depicted above and the appended drawings are exemplary and are not intended to limit the scope of the present disclosure.