Extreme ultraviolet laser marking fθ shot and laser processing device

Abstract

An Fθ lens for extreme ultraviolet laser marking assembly and a laser processing device are provided. The lens assembly includes a first lens (L), a second lens (L), a third lens (L), and a fourth lens (L) successively coaxially arranged along a transmission direction of an incident laser. The first lens (L) is a biconcave negative lens; the second lens (L) is a falcate negative lens; the third lens (L) is a falcate positive lens; and the fourth lens (L) is a biconvex positive lens; and an intermediate part of the second lens (L) and the third lens (L) are both convex toward a transmission direction of the laser. A proportion of the refractive index of the first, the second, the third and the fourth lenses to the abbe number is 1.476/68, with a tolerance of 5%. By means of the design of the four lenses and relative positions therebetween, astigmatism and distortion are effectively corrected, and the focusing degree of the energy is high. Imaging and marking of high quality are achieved; imaging quality is improved, and the structure of the lens assembly is simple, which is convenient for designing and appropriate for various laser processing devices.