Verbatim \ Blu-ray HD DVD - Manual (Page 4)

What is HD DVD?
High Density
HD DVD stands for ‘High-Density Digital Versatile Disc’. It
is promoted by Toshiba, NEC and others and is supported
by four major fi lm studios. Our parent company, Mitsubishi
Kagaku Media, is a member of the HD DVD development
technology group which means that Verbatim has access
to the latest in HD DVD technology.
The HD DVD disc, like the Blu-ray disc has a higher storage
capacity using the same blue laser of 405nm wavelength
compared to the standard red laser used in CD (780nm)
and DVD (650nm) technology. However, HD DVD uses a
lens system with a numerical aperture of 0.65 resulting in
a slightly bigger laser spot. This makes the laser and disc
less susceptible to scratches and fi ngerprints so that HD
DVD requires no hard coating on the disc surface.
How a HD DVD Disc Works
Red Laser (DVD)
technology Blue Laser (HD DVD)
technology
Data
Laser
Disc Label
Minimum pit length = 0.173μm Track pitch = 0.40μm Capacity = 15GB
Data
Polycarbonate Layer 1
Recording Layer
Refl ective Layer
Polycarbonate Layer 2
Disc Label
Minimum pit length = 0.4μm Track pitch = 0.74μm Capacity = 4.7GB
Polycarbonate Layer 1
Recording Layer
Refl ective Layer
Polycarbonate Layer 2