Patent ID: 8581949

Claim:
A laser marking method of forming a marking pattern on a marking object by irradiating the marking object with pulses repeatedly outputted from a pulsed light source so that each spot size of the outputted pulses corresponds to one of dots constituting the marking pattern, comprising: preparing the pulsed light source of a master oscillator and power amplifier structure in which a semiconductor laser outputting for the pulses is used as a seed light source, repeatedly emitting first pulses each having a first pulse duration from the pulsed light source; sweeping the first pulses and irradiating a first region with the first pulses, the first region being a first marking region on the marking object; repeatedly emitting second pulses each having a second pulse duration from the pulsed light source, the second pulse duration being different from the first pulse duration; and sweeping the second pulses and irradiating a second region with the second pulses, the second region being a second marking region on the marking object, wherein the first and second pulse durations are changed in correspondence with a repetition frequency of the pulses outputted from the pulsed light source.