The effect of microscopic features upon the transmissivity of enclosed laser ablated laminated metallised polymer films

Abstract

A vacuum-deposited aluminium layer (∼20 nm) is sandwiched between two layers of laminated oriented polypropylene (OPP) film whose thickness varies from 20 to 40 μm . Selected areas of this sealed system were transparentised by the redistribution of the aluminium layer without breaking the seal or causing damage to the OPP film using a 75 W Q-switched Nd:YAG laser. The resultant transparentised films contain aluminium particles, distorted polymer areas and intact areas of the vacuum-coated aluminium layer. This paper investigates the effect of microscopic features upon the overall transmissivity of the laser-treated films and hence the quality of the transparentisation process.