Quote:
Originally Posted by KiwiJochen
Really?
"First off, yes, the CD laser and the DVD laser are different. The light
from a DVD laser has a wavelength of 640 nanometers where the light from a
CD laser is 780 nanometers. The smaller DVD laser wavelength allows it to
focus on the smaller pits in the DVD disk. Thus, accounting for the
increase in storage capacity."
You cannot generate light of 2 different wavelengths from one laser
ergo: there are two lasers, one for CD @ 790nm, one for DVD @ 640nm
This is why when the DVD laser fails, the CDs can still be read. Because there are two different lasers
When you replace the laser, you replace the laser "assembly", which is a unit made up of both lasers and the necessary optics.
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Jochen. Yes you are right. It is always a bit confusing to talk about the laser unit. The only thing we can exchange is (as you wrote) the "laser assembly" which consist of 2 different laser diodes (for DVDs and CDs) plus optics plus.....