Are blue lasers used in DVDs?
The readout laser for DVDs is red, around 650 nm. This is similar in color to a typical red LED. Some people seem to think blue lasers are used for DVDs. One reason may be that manufacturers are putting blue illumination on the front panels and maybe even inside the disc compartment of DVD players – solely for marketing reasons. However, blue or UV lasers (e.g., argon or krypton ion) may be used to write the glass master for DVD (as well as CDs) where the shorter wavelength results in crisper more accurate rendition of the pits and lands of the information layer. Of course, these machines cost $250,000. Converting to a shorter wavelength laser for readout won’t help anything except the manufacturer’s bottom line assuming they could charge much more for the hype than the additional cost of the laser. Currently, the only viable option is the Nichia 400 nm violet laser diode which go for about $2K each! To take advantage of a shorter wavelength laser, the entire standard would need to be
