How does a CD Writer Write CDs?
First of all we need to understand how a CD (compact disc) works, a good place to look at is How Stuff Works: http://www.howstuffworks.com/cd1.htm Then we need to think about how a CD-R (CD – Recordable) works. These are written in a different way to factory ‘burned’ CDs. Again try http://www.howstuffworks.com/question287.htm for a more detailed explanation, but basically CD-R’s have an extra layer made of dye between the plastic bottom protective layer and the reflective aluminium or gold layer, which can be modified by a laser to create non-reflective areas or dots on the disc. The laser writes these dots onto the disc by heating up the dye which causes it to change and so it nolonger allows the light to be reflected. These areas that do not reflect the light is what both CD and CD-R machine read to get the information from the CD. When you write data to a CD-R, the writing laser (which is much more powerful than the reading laser) heats up the dye layer and changes its transparency.
