A method of manufacturing a light guide in the form of a plate having a face with a plurality of diffusing patterns obtained by means of a laser beam, wherein said face is exposed to radiation of intensity lying in the range 104 W/cm2 to 107 W/cm2, in particular in the range 3104 W/cm2 to 3106 W/cm2,...http://www.google.com.au/patents/US6467922?utm_source=gb-gplus-sharePatent US6467922 - Method and apparatus for laser machining light guides, light guides obtained thereby, and back-lit screens incorporating such light guides
