Polymeric optical disk recording media

Abstract

Abstract High-speed, instantaneous optical recording by use of a laser is finally emerging from the laboratory as a powerful new technology for information storage. The technique offers the capability for low-cost, high-capacity data storage with rapid. random-access retrieval. Materials that have been evaluated for laser marking vary from thin metal films (particularly tellurium [Te] and its alloys) to organiclpolymeric-based systems. The challenge to find appropriate materials is a significant one — high marking sensitivity at an appropriate wavelength coupled with long-term stability of the recording medium and the recorded information. The medium must support several other important performance considerations. The signal-to-noise ratio (SNR) of recorded information should be high to facilitate data retrieval, and the defect density level should be extremely low to minimize errors. It is desirable for the medium to be read immediately (microseconds) after the marking event (direct read after write [DRAW]). and this eliminates materials requiring postimage proc- essing or slow image development. The DRAW capability is particularly important in pro- viding relief from the stringent reliability demands (< 1 error in 1013 bits) since data signals can be verified during the record cycle and immediately corrected in some preselected segment o f the disk surface.