How does Blu-ray technology work?
A small introduction to Blu-ray
Blu-ray works in much the same way as DVD. Movies,
TV shows, and/or music are stored on a 12cm disc (the same diameter as a
standard CD). When you put the disc into a compatible player and press
play, a laser reads the data stored on the disc in the form of tiny
pits. The pitted and unpitted areas of the disc translate into digital
1s and 0s, which are decoded by the player into video, sound, menus, and
interactive bonus materials.
The most significant difference between DVD and Blu-ray is that the
latter features much tinier pits—0.15 microns long, as opposed to 0.4
microns for DVD. Thus, far more pits can be squeezed onto the same
surface area. Those tinier pits must be read by a more precise laser
than DVD’s relatively thick red beam, though, which is where the
shorter-wavelength, bluer laser of Blu-ray comes in. That’s also where
the format gets its name.
As you may have already guessed, more pits equals more bits, so a Blu-ray
Disc can hold a lot more information than a DVD—a single-layer Blu-ray
Disc holds 25 GB, compared to a single-layer DVD’s 4.7 GB; a dual-layer
Blu-ray tips the scales at 50 GB, while a dual-layer DVD holds roughly
8.5 GB.
