http://www.pioneer.eu/eur/content/press ... luray.html
A 20-layer optical disc is now viable, following research by our team of engineers at Pioneer HQ, Tokyo. Each layer of the disc can store 25GB of information to provide a mammoth 500GB of storage.
The news follows the International Symposium on Optical Memory (ISOM) and Optical Data Storage, held during July in Hawaii, where Pioneer Corporation presented its research, defining draft specifications for the 500 GB disc.
The ISOM had previously outlined the industry objective of creating a 20-layer disc to be available between 2010-2012.
With its strong support among the gaming, movie and PC industries, Blu-ray has become the de facto next generation storage system. While Blu-ray discs (BD), offering both 25GB and 50BG, are sufficient for current demands, we see the need for a technology that can support far greater capacities as HD streaming in particular becomes commonplace and users build larger files of digital content.
The multi-layered method is compatible with Blu-ray devices providing a long term future for the technology and is more easily produced when compared to competing technologies such as holographic storage.
One of the technical issues addressed was the problem of ‘crosstalk’ between the separate layers of optical media. Due to the close proximity of the layers, data from one layer could interfere with that from another layer. By applying proprietary technology developed for its BD products and by stacking two different thickness of layers alternatively, interlayer crosstalk was reduced, thus further confirming the feasibility of 20-layer optical discs.