Laser microperforation of thermoplastic or cellulosic films by means of optical fibres

摘要

A system has laser source(s) coupled to cable(s) with optical fibres. A matrix supports the other ends of the fibres so they form a line. The light from the fibres passes through a homogenising and focussing device in order to produce micro-perforations in a film. The laser light may be ultraviolet. The optical fibres have a cast silicon or quartz core, sheathed with doped silicon. Each sheath is 4 times larger than the micro-perforation produced by its fibre. The homogenising and focussing device may be a micro-lens adjacent the end of each fibre or a conical end to the fibre.