A recordable compact disc comprises a 0.6 millimeter clear plastic or glass substrate on which is grown a thin-film image layer having several distinct recording planes. Each recording plane is separated from the next by a clear plastic layer. Each recording plane includes an organic dye ...http://www.google.com.hk/patents/US5669995?utm_source=gb-gplus-share專利 US5669995 - Method for writing and reading data on a multi-layer recordable interferometric optical disc and method for fabricating such 
