This section describes background subject matter related to the disclosed embodiments of the present invention. There is no intention, either express or implied, that the background art discussed in this section legally constitutes prior art.
Nanostructuring is necessary for many present applications and industries and for new technologies which are under development. Improvements in efficiency can be achieved for current applications in areas such as solar cells and LEDs, next generation data storage devices, architectural glass and bio- and chemical sensors, for example and not by way of limitation.
Nanostructured substrates may be fabricated using techniques such as e-beam direct writing, Deep UV lithography, nanosphere lithography, nanoimprint lithography, near-field phase shift lithography, and plasmonic lithography, for example.
There is a need to identify nanostructures produced using specific equipment and process in order to protect and enforce Intellectual Property (IP) rights. Some desirable features for anti-counterfeiting features/systems are a) they should be quite difficult to find and/or replicate; b) they should be manufactured using mass production methods in order to keep added cost down; and c) flexibility to change the anti-counterfeiting system frequently to avoid adoption of the method or system by counterfeiters.
Various approaches have been proposed for counterfeit prevention and for authentication of documents or valuable articles. Some of these methods are clearly visible to the naked eye and are intended for the general public, while others are hidden and only detectable by the competent authorities, or by automatic devices. For example, some methods use special paper, special inks, watermarks, micro-letters, security threads, holograms, etc. Nevertheless, there is still an urgent need to develop and or embed anti-counterfeiting features or systems to a nanostructured device seamlessly and non-intrusively.
It is within this context that the present invention arises.