Patent ID: 9733453
Date: 2017-08-15
CPC Classifications: G02B

Claim:
1. An imaging optical system comprising, in order from an object side to an image side: a first lens element having positive refractive power in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof; a second lens element having negative refractive power in a paraxial region thereof; a third lens element; a fourth lens element with at least one of an object-side surface and an image-side surface thereof having at least one inflection point; a fifth lens element having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof; wherein both of the object-side surface and the image-side surface of the fifth lens element are aspheric; and a sixth lens element with positive refractive power in a paraxial region thereof having an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof; wherein both of the object-side surface and the image-side surface of the sixth lens element are aspheric, and the image-side surface of the sixth lens element has at least one inflection point; wherein the imaging optical system has a total of six lens elements; wherein a focal length of the imaging optical system is f, a curvature radius of the image-side surface of the fourth lens element is R8, an axial distance between the fourth lens element and the fifth lens element is T45, a central thickness of the fifth lens element is CT5, and the following conditions are satisfied: