Laser marking

摘要

A method and apparatus is disclosed for producing precision marks (28) for a metrological scale in the form of a stainless steel ribbon (10). A laser (21) is used to produce ultra-short pulses, which have a fluence at the ribbon such that ablation takes place. The laser light can be scanned via scanner (25) and the pitch of the marks (28) can be controlled. The ablative technique causes little thermal input and improves the accuracy of the scale.