De La Rue International Limited

Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Cambridge Enterprise Limited

Götz Peter Hellmann

Jeremy John Baumberg

David Snoswell

Günther Vulpius

Peter Wolfgang Andreas Spahn

Christopher Finlayson

Qibin Zhao

Christian Gerhard SCHÄFER

A method of forming a film of photonic crystal material. A first process is performed upon a material capable of having a photonic crystal structure, this process causing deformation of the material so as to form a film in which incident light received by the material is selectively reflected or transmitted to generate a first optical effect in the film. A second process is performed upon substantially all of the film which applies a shear stress to the film. This causes a change in the material structure so as to generate a second optical effect in the film, different from the first optical effect, in response to incident light. Security films, devices, articles and documents formed using the method are also discussed.

Method of forming a photonic crystal material

Growing community of inventors

Mainz, Germany

Götz Peter Hellmann