Recording process of recordable compact disc

Abstract

A recordable compact disc (CD-R), developed by the authors in 1988, is now widely used for professional audio and data applications. It is a write-once optical disc consisting of a polycarbonate substrate, a light absorbing layer of dyes, a light reflecting layer of metal, and a protective layer. The main features of CD-R compared with other recordable optical discs are its high reflectivity of more than 70% and a large modulation amplitude of around 75% for compatibility with existing compact disc (CD) systems. The disc structure for achieving such high reflectivity and some analyses of the recording mechanism were reported by the authors in 1989. Further discussions on the recording mechanism were made by Holtslag et. al. in 1991. However, those papers did not clarify the mechanism of obtaining the large signal modulation. This paper reports that both the decomposition of dye in the light absorbing layer during recording and the deformation of the substrate surface are the key factors causing the large modulation of the CD-R.