Optical imaging system, image capturing unit and electronic device

摘要

An optical imaging system includes, in order from an object side to an image side, a first lens element, a second lens element and a third lens element. The first lens element with positive refractive power has an object-side surface being convex and an image-side surface being convex in a paraxial region. The second lens element with positive refractive power has an object-side surface being concave and an image-side surface being convex in a paraxial region. The third lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the third lens element has at least one convex shape in an off-axis region thereof. The optical imaging system further comprises a stop between the image-side surface of the first lens element and the object-side surface of the second lens element. The lens elements are made of plastic material.

主权项

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 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 first lens element are aspheric, and the first lens element is made of plastic material; a second lens element with positive refractive power 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 second lens element are aspheric, and the second lens element is made of plastic material; and a third lens element with negative refractive power having an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the third lens element has at least one convex shape in an off-axis region thereof, both of an object-side surface and the image-side surface of the third lens element are aspheric, and the third lens element is made of plastic material; wherein the optical imaging system has a total of three lens elements with refractive power which are the first lens element, the second lens element and the third lens element, the optical imaging system further comprises a stop located between the image-side surface of the first lens element and the object-side surface of the second lens element; wherein a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, a central thickness of the first lens element is CT1, a central thickness of the third lens element is CT3, 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 the following conditions are satisfied:
|f3|