The writing process: CD-R


Digital information is written to the disc by burning (forming) pits in the recording layer.The energy of the laser beam - in the range 4 to 11 mW - causes limited heating of the substrate and recording layer to approximately 250C. At this temperature the recording layer melts, reducing its volume, while the substrate expands into the space that becomes available. By constant switching between writing and reading power, a pit pattern corresponding to that of a conventional CD is produced.

The write pulse initially has a higher power to produce the required heating of the dye. Subsequently, the power is reduced to a level that is sufficient to maintain the dye temperature at the desired level.

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