Image pickup optical lens assembly

Abstract

This invention discloses an image pickup optical lens assembly, sequentially arranged from an object side to an image side along an optical axis, comprising: the first lens element with positive refractive power having a convex object-side surface, the second lens element with negative refractive power, the third lens element with refractive power, the fourth lens element with positive or negative refractive power having a concave object-side surface and a convex image-side surface with both being aspheric, and the fifth lens element with positive or negative refractive power having a convex object-side surface and a concave image-side surface with both being aspheric. Additionally, the image pickup optical lens assembly satisfies conditions related to the reduction of the total length and the sensitivity of the image pickup optical lens assembly for compact cameras and mobile phones with camera functionalities.

What is claimed is: 
     
         1 . An image pickup optical lens assembly from an object side to an image side comprising:
 a first lens element with positive refractive power;   a second lens element having a convex object-side surface;   a third lens element;   a fourth lens element with negative refractive power having a concave object-side surface, and both the object-side surface and an image-side surface thereof being aspheric; and   a fifth lens element having a concave image-side surface, the image-side surface of the fifth lens element having at least one inflection point, and both an object-side surface and the image-side surface thereof being aspheric;   wherein the image pickup optical lens assembly has a total of five lens elements, CT 4  is a thickness of the fourth lens element near the optical axis, CT 5  is a thickness of the fifth lens element near the optical axis, f is a focal length of the image pickup optical lens assembly, f 4  is a focal length of the fourth lens element, f 5  is a focal length of the fifth lens element, and the following relations are satisfied:
   0.2< CT   4   /CT   5 <0.9; and 
   | f/f 4|+| f/f 5|<0.6. 
   
     
     
         2 . The image pickup optical lens assembly of  claim 1 , wherein the second lens element has negative refractive power, and the second lens element has a concave image-side surface. 
     
     
         3 . The image pickup optical lens assembly of  claim 1 , wherein the third lens element has positive refractive power. 
     
     
         4 . The image pickup optical lens assembly of  claim 1 , wherein the fifth lens element has negative refractive power, and the fifth lens element is made of plastic. 
     
     
         5 . The image pickup optical lens assembly of  claim 1 , wherein the fourth lens element has a convex image-side surface. 
     
     
         6 . The image pickup optical lens assembly of  claim 1 , further comprising a stop, wherein the fifth lens element has a convex object-side surface, Sd is an axial distance from the stop to the image-side surface of the fifth lens element, Td is an axial distance from an object-side surface of the first lens element to the image-side surface of the fifth lens element, and the following relation is satisfied:
   0.75< Sd/Td< 1.2.   
     
     
         7 . The image pickup optical lens assembly of  claim 1 , further comprising a stop disposed between the first lens element and an object to be photographed, wherein Sd is an axial distance from the stop to the image-side surface of the fifth lens element, Td is an axial distance from an object-side surface of the first lens element to the image-side surface of the fifth lens element, and the following relation is satisfied:
   0.9< Sd/Td< 1.1.   
     
     
         8 . The image pickup optical lens assembly of  claim 1 , further comprising an image sensor at an image plane, wherein TTL is an axial distance from an object-side surface of the first lens element to the image plane, ImgH is half of the diagonal length of an effective photosensitive area of the image sensor, and the following relation is satisfied:
     TTL/ImgH≦ 1.75.   
     
     
         9 . The image pickup optical lens assembly of  claim 1 , wherein v 1  is an Abbe number of the first lens element, v 2  is an Abbe number of the second lens element, and the following relation is satisfied:
   28< v   1   −v   2 <42.   
     
     
         10 . The image pickup optical lens assembly of  claim 1 , wherein CT 4  is the thickness of the fourth lens element near the optical axis, CT 5  is the thickness of the fifth lens element near the optical axis, and the following relation is satisfied:
   0.2< CT   4   /CT   5 <0.7.   
     
     
         11 . The image pickup optical lens assembly of  claim 1 , wherein CT 4  is the thickness of the fourth lens element near the optical axis, CT 5  is the thickness of the fifth lens element near the optical axis, and the following relation is satisfied:
   0.2< CT   4   /CT   5 <0.55.   
     
     
         12 . The image pickup optical lens assembly of  claim 1 , wherein the thickness of the fifth lens element near the optical axis is the largest among thicknesses near the optical axis of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element; both of the object-side surface and the image-side surface of the fifth lens element have at least one inflection point. 
     
     
         13 . The image pickup optical lens assembly of  claim 1 , wherein an axial distance between the third lens element and the fourth lens element is the largest among axial distances between every two of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element that are adjacent to each other. 
     
     
         14 . The image pickup optical lens assembly of  claim 1 , wherein the focal length of the fourth lens element has the largest magnitude among focal lengths of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element. 
     
     
         15 . The image pickup optical lens assembly of  claim 1 , wherein a focal length of the third lens element has smaller magnitude than the focal lengths of the fourth lens element and the fifth lens element. 
     
     
         16 . An image pickup optical lens assembly from an object side to an image side comprising:
 a first lens element with positive refractive power;   a second lens element having a convex object-side surface;   a third lens element;   a fourth lens element with negative refractive power having a concave object-side surface, and both object-side surface and image-side surface thereof being aspheric; and   a fifth lens element having a concave image-side surface, the image-side surface of the fifth lens element having at least one inflection point, and both object-side surface and image-side surface thereof being aspheric;   wherein the image pickup optical lens assembly has a total of five lens elements, CT 4  is a thickness of the fourth lens element near the optical axis, CT 5  is a thickness of the fifth lens element near the optical axis, f is a focal length of the image pickup optical lens assembly, f 4  is a focal length of the fourth lens element, f 5  is a focal length of the fifth lens element, and the following relations are satisfied:
   0.2< CT   4   /CT   5 <0.7; and 
   | f/f 4|+| f/f 5|<1.8. 
   
     
     
         17 . The image pickup optical lens assembly of  claim 16 , wherein the second lens element has negative refractive power, and the second lens element has a concave image-side surface. 
     
     
         18 . The image pickup optical lens assembly of  claim 17 , wherein f is the focal length of the image pickup optical lens assembly, f 4  is the focal length of the fourth lens element, f 5  is the focal length of the fifth lens element, and the following relation is satisfied:
   | f/f 4|+| f/f 5|<0.6.   
     
     
         19 . The image pickup optical lens assembly of  claim 17 , wherein v 1  is an Abbe number of the first lens element, v 2  is an Abbe number of the second lens element, and the following relation is satisfied:
   28< v   1   −v   2 <42.   
     
     
         20 . The image pickup optical lens assembly of  claim 16 , wherein the third lens element has positive refractive power and a convex image-side surface. 
     
     
         21 . The image pickup optical lens assembly of  claim 16 , wherein the fifth lens element has a convex object-side surface, and the fifth lens element is made of plastic. 
     
     
         22 . The image pickup optical lens assembly of  claim 16 , wherein the fourth lens element has a convex image-side surface. 
     
     
         23 . The image pickup optical lens assembly of  claim 16 , further comprising a stop, wherein Sd is an axial distance from the stop to the image-side surface of the fifth lens element, Td is an axial distance from an object-side surface of the first lens element to the image-side surface of the fifth lens element, and the following relation is satisfied:
   0.75< Sd/Td< 1.2.   
     
     
         24 . The image pickup optical lens assembly of  claim 16 , further comprising a stop disposed between an object to be photographed and the first lens element, wherein Sd is an axial distance from the stop to the image-side surface of the fifth lens element, Td is an axial distance from an object-side surface of the first lens element to the image-side surface of the fifth lens element, and the following relation is satisfied:
   0.9< Sd/Td< 1.1.   
     
     
         25 . The image pickup optical lens assembly of  claim 16 , further comprising an image sensor at an image plane, wherein TTL is an axial distance from an object-side surface of the first lens element to the image plane, ImgH is half of the diagonal length of an effective photosensitive area of the image sensor, and the following relation is satisfied:
     TTL/ImgH≦ 1.75.   
     
     
         26 . The image pickup optical lens assembly of  claim 16 , wherein CT 4  is the thickness of the fourth lens element near the optical axis, CT 5  is the thickness of the fifth lens element near the optical axis, and the following relation is satisfied:
   0.2< CT   4   /CT   5 <0.55.   
     
     
         27 . The image pickup optical lens assembly of  claim 16 , wherein the thickness of the fifth lens element near the optical axis is the largest among thicknesses near the optical axis of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element; both of the object-side surface and the image-side surface of the fifth lens element have at least one inflection point. 
     
     
         28 . The image pickup optical lens assembly of  claim 16 , wherein an axial distance between the third lens element and the fourth lens element is the largest among axial distances between every two of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element that are adjacent to each other. 
     
     
         29 . The image pickup optical lens assembly of  claim 16 , wherein the focal length of the fourth lens element has the largest magnitude among focal lengths of the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element. 
     
     
         30 . The image pickup optical lens assembly of  claim 16 , wherein a focal length of the third lens element has smaller magnitude than the focal lengths of the fourth lens element and the fifth lens element, a focal length of the second lens element has smaller magnitude than the focal length of the third lens element, and a focal length of the first lens element has smaller magnitude than the focal length of the second lens element.