Unrecordable media have a series of pits and lands on their tracks
as in the figures above. These pits and lands mean that already there
are recorded data in the media.
Contrary to unrecordable media, CD-ROM doesn't have pits or lands
on its track. Instead, there is guide groove where user's data are
written.
Cross Section Structure
CD-R Structure
CD-R is layered like this, from bottom to top:
Substrate to maintain the form,
Recording Layer to record signals,
Reflective Layer to reflect laser light during playback,
Protective Layer to protect the reflective coating, and
Label for brand name printing
Layer Materials & Their Main Features
Layers
Materials
Main Features
Label
UV Curable lnk
Printability
Lacquer
UV Curable Polyacrylate Resin
Resistance to environmental stress
cracking
Refle ctive layer
Gold or Silver
Reflectivity, Chemical stability
Recording layer
Organic dye compounds
Sensitivity, Stability
Substrate
Polycarbonate(PC) Resin
Transfer, Double refraction
Pre-groove
Width/Depth
Recording
Cross Section Structure of CD-RW
Layer Functions
Layer
Function
Recording Layer
Phase change recording or erasing
Dielectric Layer
Protecting recording layer /
Increasing signal amplitude
Reflective Layer
Heightening optical efficiency /
Preventing oxidation of recording layer
Substrate to maintain the form,
Layer Materials & Their Main Features
