Infrared large-format telecentric laser marking f theta lens

Abstract

An Fθ lens for infrared large-format telecentric laser marking is disclosed, including a first lens element, a second lens element, a third lens element and a fourth lens element arranged sequentially along the propagation direction of an incident ray. The first lens element is a negative biconcave lens element including a first curved surface and a second curved surface. The second lens element is a positive meniscus lens element including a third curved surface and a fourth curved surface. The third lens element is a positive meniscus lens element including a fifth curved surface and a sixth curved surface. The fourth lens element is a plane lens adapted to play a role in protecting other lens elements. The first to third lens elements are arranged around a same axis along the propagation direction of the incident ray. The first to sixth curved surfaces are arranged sequentially along the propagation direction of the incident ray. The above Fθ lens for infrared large-format telecentric laser marking can be used as an Fθ lens for infrared laser marking, which can meet the telecentric requirement of the large-format laser marking, and control the volume of the lens within an acceptable and applicable range, to achieve miniaturizing of the whole optical system.