| 摘要 |
A transparent thermoplastic part (12) is welded by a laser beam (16) to an absorbent thermoplastic part (14). In order to produce markings, e.g. a barcode, the wavelength is then changed so that it is largely absorbed by the first part (12). The first part (12) can contain a dye so that it absorbs visible light but transmits light in the infra-red region. An Independent claim is also included for an arrangement for welding and marking that includes a laser and optics (40) and means to alter the wavelength of the beam (16), e.g. for doubling (54) or tripling the frequency. The mirror (50) can be replaced by a scanner to produce an extended weld zone and provide markings. |
