Micro-lens group for obtaining adjustable annular light beam

Abstract

The invention discloses a micro-lens group for obtaining an adjustable annular light beam. The micro-lens group comprises a plano-concave micro-lens and a plano-convex micro-lens, is novel in structural design. According to the micro-lens obtained based on combination of axicon light splitting and angular light splitting, under incidence of parallel or nearly parallel circular light beams, one micro-lens is rotated by a small angle along a light beam transmission axis, and a focusing lens is matched to obtain a focusing light beam, so that a solid light spot of a focusing focus is converted into an annular light spot, and the diameter of the annular light spot is continuously adjustable; while the spot diameter and the edge energy distribution are increased, the focal depth length of a focused light beam section can be greatly increased, the plate cutting speed, the section quality, the perpendicularity and the cutting thickness can be improved, and the method is particularly suitablefor medium and thick plate cutting application of a continuous fiber laser with the fiber core diameter of 50 microns or above.

Description

technical field [0001] The invention relates to the technical field of fiber laser cutting, in particular to a microlens group for obtaining an adjustable ring beam. Background technique [0002] Due to the advantages of high electro-optical conversion efficiency, good fiber flexibility, high coupling efficiency, and good beam quality, as well as the emergence of high-power lasers, fiber lasers have made their market share increasingly prominent. At present, fiber-coupled output lasers of kilowatt level are quite popular. Watt-level lasers are gradually released to the market, making fiber laser processing more and more common. [0003] The laser cutting application of fiber laser covers various metal processing markets such as stainless steel, carbon steel, aluminum, copper, etc. With the increase of laser power, the cutting thickness of plates of different materials becomes thicker. [0004] As we all know, although the conventional aberration-absorbing optical configurat...

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Problems solved by technology

The single-piece axicon lens cannot realize the adjustable annular spot, which is not conducive to the process optimization of plates with different thicknesses; the HighYAG free-form surface lens group requires multi-dimensional coordination and adjustment of the double-piece free-form surface lens group, and additionally requires the movement of the collimator or focusing lens to cooperate with compensation The focus position increases the difficulty of mechanical design and control, and the mirror surface processing is very difficult; the Pr

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