What is DVD R ?

Thu, 14 Feb 2008 04:20:00 EST

DVD-R format was developed by Pioneer in 1997. It is supported by most DVD players, and is approved by the DVD Forum. The larger capacity of a DVDR (4.7GB) compared to a CD-R (700MB) is achieved through smaller pit size and smaller track pitch of the groove spiral which guides the laser beam. So, more can be written on the same physical sized disc. In order to write smaller pits onto the recording dye, a laser beam with a shorter wavelength to that of CDR is used. DVD-R and DVD+R use different dyes from CD-R to properly absorb this wavelength.

DVD-R discs are made of two thin polycarbonate discs, bonded together with an adhesive. One contains the laser guiding groove and is coated with the recording dye and a reflecting alloy. The other one (for single-sided discs) is an ungrooved "dummy" disc to assure mechanical stability and compatibility with the compact disc standard which requires a total disc thickness of 1.2 mm. This sandwich structure also helps protect the data layer from scratches by a thick "dummy" disc, a problem you get with CDs because they lack this structure.

Double-sided discs have two grooved, recordable disc sides, and require the user to flip the disc to access the other side. Compared to a CD's 1.2 mm of polycarbonate, a DVD laser beam only has to penetrate 0.6 mm of plastic in order to reach the dye recording layer, which allows the lens to focus the beam to a smaller size.

Blank DVD R in UK

Thu, 31 Jan 2008 09:43:00 EST

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What is DVD R ?

Blank DVD R in UK