Beam scanning type laser marking device

Abstract

A beam scanning type laser marking device suitable for forming minute dot marks which can ensure the visibility is provided. In this beam scanning type laser marking device which performs a marking on a surface to be marked through a convergence lens system by scanning laser beams irradiated from a laser oscillator in a given pattern using a scanning mirror, the convergence lens system is comprised of three or more convergence lenses, a focal length of an fθ lens which is arranged at a position closest to the scanning mirror side is set to a distance which prevents the fθ lens from interfering with a first scanning mirror which is arranged to face the fθ lens in an opposed manner, and the center of the first scanning mirror is arranged to coincide with a front-side focal position of the fθ lens, and the convergence lens system has lenses thereof sequentially arranged in a telecentric relationship. As a result, an offset amount of a formed image can be minimized so that a dot interval which does not give an influence to the visibility even with dot marks of minute configuration can be ensured.

Dependencies are inferred from the claim text.