Image capturing system

摘要

An image capturing system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has a convex object-side surface at a paraxial region. The second lens element and the third lens element have refractive power. The fourth lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region. The fifth lens element with refractive power has an image-side surface, wherein the image-side surface changes from concave at a paraxial region to convex at a peripheral region, and an object-side surface and the image-side surface of the fifth lens element are aspheric. The image capturing system has a total of five lens elements with refractive power.

主权项

1. An image capturing system comprising, in order from an object side to an image side:
a first lens element with positive refractive power having a convex object-side surface at a paraxial region; a second lens element having refractive power; a third lens element having refractive power; a fourth lens element with negative refractive power having a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; and a fifth lens element with refractive power having a concave image-side surface at a paraxial region, wherein an object-side surface and the image-side surface of the fifth lens element are aspheric, and the shape of the image-side surface of the fifth lens element changes from concave at the paraxial region to convex at a peripheral region; wherein the image capturing system has a total of five lens elements with refractive power, an axial distance between the first lens element and the second lens element is T12, a central thickness of the second lens element is CT2, an axial distance between the third lens element and the fourth lens element is T34, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, and the following relationships are satisfied:
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