Patent ID: 9507126
Filing Date: 2016-11-29
CPC Classification: G02B

Claim Text:
1. An optical imaging system comprising, in order from an object side to an image side: a first lens element with positive refractive power having an object-side surface being convex in a paraxial region thereof; a second lens element; a third lens element having positive refractive power; a fourth lens element; a fifth lens element having an image-side surface being concave in a paraxial region thereof, wherein both of an object-side surface and the image-side surface of the fifth lens element are aspheric; and a sixth lens element having an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the sixth lens element has at least one convex shape in an off-axis region thereof, and both of an object-side surface and the image-side surface of the sixth lens element are aspheric; wherein the optical imaging system has a total of six lens elements, the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element and the sixth lens element are all stationary relative to one another in a paraxial region thereof, an air gap in a paraxial region is between every two of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element and the sixth lens element that are adjacent to each other, the optical imaging system further comprises a stop located between an imaged object and the third lens element; wherein a maximum effective radius of the image-side surface of the sixth lens element is SD62, an entrance pupil diameter of the optical imaging system is EPD, a focal length of the first lens element is f1, a focal length of the third lens element is f3, an axial distance between the object-side surface of the first lens element and the image-side surface of the sixth lens element is Td, and the following conditions are satisfied: