Toshiba D-VR3SU, Service Manual

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2-1
2. Reference Information
2-1 Introduction to DVD
2-1-1 The Definition of DVD
DVD is the next generation medium and is the acronym of the Digital Versatile Disc or thr Digital Video Disc,
which maximizes the saving density of the disk surface using the MPEG-2 compression technology to enable the
storage of 17G bytes of data on the same size CD.
1) 7 times the storage capacity of the conventional CD
•
Minimized the track pitch and pit size to 1/2 of conventional CD.
•
Uses red laser with short-wavelenght of 650nm (635nm).
•
DVD Vs. CD-ROM
CD-ROM CD-R/RW DVD-ROM DVD-R/RW DVD-RAM
Disc Thickness 1.2mm 1.2mm 0.6*2mm 0.6*2mm 0.6*2mm
Lens NA 0.45 0.45(0.5) 0.6 0.6 0.6
Laser wavelenght 780um 780um 650um 650um 650um
Track pitch 1.6pm 1.6pm 0.74pm 0.74pm 0.615pm
Capacity 0.65GB 0.65GB 4.7GB 4.7GB 4.7GB
Track structure Pit train Groove Pit train Groove Land/Groove
2) Disc Formats
DVD consists of two 0.6mm discs attached together, enabling access to the upper and lower side of the disk,
and 4 sides could be used at maximum.
Single Layer : 4.7GByte
Polycarbonate
Label
Bonding layer
Reflective layer
Polycarbonate
Label
Polycarbonate
Bonding layer
Reflective layer
Semi-reflective layer
Polycarbonate
Dual Layer : 8.5GByte
Bonding layer
Reflective layer
Reflective layer
Polycarbonate
Polycarbonate
Dual Side Single Layer : 9.5GByte
Polycarbonate
Bonding layer
Reflective layer
Reflective layer
Semi-reflective layer
Semi-reflective layer
Polycarbonate
Dual Side Dual Layer : 17GByte