OPTICAL LENS ASSEMBLY FOR IMAGE TAKING

摘要

An optical lens assembly for image taking includes a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element with positive refractive power includes a convex object-side surface at a paraxial region. The second lens element with negative refractive power includes a concave object-side surface at a paraxial region. The third lens element with refractive power includes a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region. The fourth lens element made of plastic with negative refractive power includes a concave object-side surface at a paraxial region and an image-side surface. Both of the object-side surface and the image-side surface of the fourth lens element are aspheric, and the image-side surface of the fourth lens element is concave at a paraxial region and convex at a peripheral region.

主权项

1. An optical lens assembly for image taking comprising, in order from an object side to an image side:
a first lens element with positive refractive power comprising a convex object-side surface at a paraxial region and an image-side surface; a second lens element with negative refractive power comprising a concave object-side surface at a paraxial region and an image-side surface; a third lens element with refractive power comprising a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; and a fourth lens element made of plastic with negative refractive power comprising a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region wherein both of the object-side surface and the image-side surface are aspheric, and the image-side surface is convex at a peripheral region; wherein the optical lens assembly for image taking has a total of four lens elements with refractive power, T23 is an axial distance between the second lens element and the third lens element, CT3 is a central thickness of the third lens element, R1 is a curvature radius of the object-side surface of the first lens element, R2 is a curvature radius of the image-side surface of the first lens element, Dr1r4 is an axial distance between the object-side surface of the first lens element and the image-side surface of the second lens element, and the optical lens assembly for image taking satisfies the following conditions:
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