Imaging lens having four lens elements, and electronic apparatus having the same

Abstract

An imaging lens includes a first lens element, a second lens element, a third lens element, and a fourth lens element arranged from an object side to an image side in the given order. The first lens element has positive refractive power and an image-side surface with a concave portion in the vicinity of an optical axis. The object-side surface of the third lens element has a concave portion in a vicinity of an optical axis of the imaging lens. The object-side surface of the fourth lens element has a convex portion in a vicinity of the optical axis of the imaging lens. The imaging lens does not have any lens element with refractive power other than the first, second, third, and fourth lens elements.

What is claimed is: 
     
         1 . An imaging lens comprising a first lens element, a second lens element, a third lens element, and a fourth lens element arranged from an object side to an image side in the given order, each of the first, second, third, and fourth lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein:
 the first lens element has positive refractive power;   the image-side surface of the first lens element comprises a concave portion in a vicinity of an optical axis of the imaging lens;   the object-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis;   the object-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis; and   the imaging lens does not include any lens element with refractive power other than the first, second, third, and fourth lens elements,   wherein the imaging lens satisfies 1.900≤ALT/(G 34 +T 4 )≤2.614, where ALT represents a sum of thicknesses of all four lens elements along the optical axis, G 34  represents a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis, and T 4  represents a distance between the object-side surface and the image-side surface of the fourth lens element at the optical axis.   
     
     
         2 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 0.882≤(G 23 +G 34 )/T 4 ≤2.116, where G 23  represents a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis. 
     
     
         3 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 1.308≤(T 1 +G 12 +G 34 )/G aa ≤2.219, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, G 12  represents a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, and G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis. 
     
     
         4 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 1.942≤(BFL+EFL)/ALT≤2.593, where BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis, and EFL represents a system focal length of the imaging lens. 
     
     
         5 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 2.255≤(EFL+T 1 )/BFL≤3.278, where EFL represents a system focal length of the imaging lens, T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, and BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis. 
     
     
         6 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 2.733≤ALT/T 1 ≤3.311, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis. 
     
     
         7 . The imaging lens of  claim 1 , wherein the imaging lens further satisfies 1.417≤(G aa +ALT)/BFL≤2.513, where G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis, and BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis. 
     
     
         8 . An imaging lens comprising a first lens element, a second lens element, a third lens element, and a fourth lens element arranged from an object side to an image side in the given order, each of the first, second, third, and fourth lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein:
 the image-side surface of the first lens element comprises a concave portion in a vicinity of an optical axis of the imaging lens;   the second lens element has negative refractive power;   the object-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis;   the object-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis; and   the imaging lens does not include any lens element with refractive power other than the first, second, third, and fourth lens elements,   wherein the imaging lens satisfies 1.900≤ALT/(G 34 +T 4 )≤2.614, where ALT represents a sum of thicknesses of all four lens elements along the optical axis, G 34  represents a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis, and T 4  represents a distance between the object-side surface and the image-side surface of the fourth lens element at the optical axis.   
     
     
         9 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 2.831≤(ALT+T 1 )/T 3 ≤5.843, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, and T 3  represents a distance between the object-side surface and the image-side surface of the third lens element at the optical axis. 
     
     
         10 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 1.733≤(T 2 +T 3 +T 4 )/T 1 ≤2.311, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, T 2  represents a distance between the object-side surface and the image-side surface of the second lens element at the optical axis, and T 3  represents a distance between the object-side surface and the image-side surface of the third lens element at the optical axis. 
     
     
         11 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 1.205≤(T 1 +G 12 )/(T 2 +G 23 )≤2.110, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, G 12  represents a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, T 2  represents a distance between the object-side surface and the image-side surface of the second lens element at the optical axis, and G 23  represents a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis. 
     
     
         12 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 1.523≤BFL/G aa ≤3.327, where BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis, and G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis. 
     
     
         13 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 2.365≤(ALT+G 12 )/G aa ≤4.650, where G 12  represents a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, and G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis. 
     
     
         14 . The imaging lens of  claim 8 , wherein the imaging lens further satisfies 1.079≤(T 1 +T 2 +T 4 )/(T 3 +G 34 )≤2.174, where T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, T 2  represents a distance between the object-side surface and the image-side surface of the second lens element at the optical axis, and T 3  represents a distance between the object-side surface and the image-side surface of the third lens element at the optical axis. 
     
     
         15 . An imaging lens comprising a first lens element, a second lens element, a third lens element, and a fourth lens element arranged from an object side to an image side in the given order, each of the first, second, third, and fourth lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein:
 the image-side surface of the first lens element comprises a concave portion in a vicinity of an optical axis of the imaging lens;   the object-side surface of the third lens element comprises a concave portion in a vicinity of the optical axis;   the fourth lens element has positive refractive power;   the object-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis; and   the imaging lens does not include any lens element with refractive power other than the first, second, third, and fourth lens elements, wherein the imaging lens satisfies 1.900≤ALT/(G 34 +T 4 )≤2.614, where ALT represents a sum of thicknesses of all four lens elements along the optical axis, G 34  represents a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis, and T 4  represents a distance between the object-side surface and the image-side surface of the fourth lens element at the optical axis.   
     
     
         16 . The imaging lens of  claim 15 , wherein the imaging lens further satisfies 2.699≤(BFL+G aa )/(G 12 +T 4 )≤4.451, where BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis, G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis, and G 12  represents a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis. 
     
     
         17 . The imaging lens of  claim 15 , wherein the imaging lens further satisfies 3.525≤EFL/G aa ≤6.481, where EFL represents a system focal length of the imaging lens, and G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis. 
     
     
         18 . The imaging lens of  claim 15 , wherein the imaging lens further satisfies 1.451≤(BFL+T 1 )/(T 2 +G 34 )≤2.737, where BFL represents a distance between the image-side surface of the fourth lens element and an image plane of the imaging lens at the optical axis, T 1  represents a distance between the object-side surface and the image-side surface of the first lens element at the optical axis, and T 2  represents a distance between the object-side surface and the image-side surface of the second lens element at the optical axis. 
     
     
         19 . The imaging lens of  claim 15 , wherein the imaging lens further satisfies 3.112≤EFL/(G 23 +T 3 )≤4.837, where EFL represents a system focal length of the imaging lens, G 23  represents a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and T 3  represents a distance between the object-side surface and the image-side surface of the third lens element at the optical axis. 
     
     
         20 . The imaging lens of  claim 15 , wherein the imaging lens further satisfies 1.740≤(ALT+G 12 )/(G 34 +G aa )≤3.550, where G 12  represents a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, and G aa  represents a sum of a distance between the image-side surface of the first lens element and the object-side surface of the second lens element at the optical axis, a distance between the image-side surface of the second lens element and the object-side surface of the third lens element at the optical axis, and a distance between the image-side surface of the third lens element and the object-side surface of the fourth lens element at the optical axis.