FOCUS ADJUSTING OPTICAL LENS ASSEMBLY

摘要

A focus adjusting optical lens assembly 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. The second lens element has negative refractive power. The third lens element has refractive power. The fourth lens element with negative refractive power has a concave object-side surface and a convex image-side surface. The fifth lens element with refractive power has a concave image-side surface at a paraxial region, wherein the image-side surface of the fifth lens element changes from concave at the paraxial region to convex at a peripheral region, and both of an object-side surface and the image-side surface of the fifth lens element are aspheric.

主权项

1. A focus adjusting optical lens assembly 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; a second lens element having negative refractive power; a third lens element having refractive power; a fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface; and a fifth lens element with refractive power having a concave image-side surface at a paraxial region, wherein the image-side surface of the fifth lens element changes from concave at the 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; wherein an object moves closer towards or further away the focus adjusting optical lens assembly, the focusing adjustment is performed by adjusting an axial distance between the first lens element and the second lens element along an optical axis; the focus adjusting optical lens assembly has a total of five lens elements with refractive power, a difference of an axial distance between the first lens element and the second lens element of the focus adjusting optical lens assembly focused on the object at a close distance and infinity is ΔT12, a central thickness of the second lens element is CT2, and the following relationship is satisfied:
0.05<|ΔT12|/CT2<0.80.