Double-Layer DVD: Lite-On, LG and BenQ

Double-layer: The Latest Technology

Just as with improvements in speed, it is the format "+" that comes out the winner. That is mainly due to the number of manufacturers involved in the DVD+RW alliance. Thus, Pioneer has been almost alone in creating the products and requiring validation from the DVD Forum. In the meantime, all those who were working on improving the DVD+RW format have been taking an active part in validating the norms. Thus, for the moment, only discs that can be recorded a single time (+R) can benefit from double-layer (DL) technology. Burners that are capable of burning a double layer carry the following logos.

How Does It Work?

The true challenge for the research engineers was to create a recordable double-layer disc that was as close as possible to pressed double-layer discs to achieve compatibility.

Like the CD, the DVD is 1.2 mm thick. But if the CD consists of a single block, the DVD consists of two discs 0.6 mm thick, stuck together. To produce these discs, several successive layers are arranged according to the following diagram: