DVD (Digital Versatile Disk) (page 3)

• Introduction
• DVD Formats
• DVD Configurations and Basic design
• DVD-R and DVD-RW or RAM
• DVD-ROM
• DVD-Video and DVD-Audio
• Red laser vs. Blue laser
• DVD--> VHS
• DVD--> DVD
• DVD R/RW Format Compatibility
• White Papers

All DVD-5 to DVD-18, like a CD, store pre-recorded information, which can not be changed. DVD-5, shown in the next figure is basically a sandwich  of two layers of 0.6 mm thick, one of which has the data and another is blank.  A thin metal layer reflects the laser beam back to the detector in a way quite similar to a CD. The difference here is in a smaller spot size, smaller bits and tighter tracks.  The label is attached to the label side in a fashion similar to a CD label.

The similarity between the DVD and the CD gets smaller with the next configuration used, DVD-9, which utilizes two layers to store the information and two laser beams to retrieve the data. Although 4.7 GB stores more data than 7 compact disks, even higher storage capacity is achieved in DVD-9 by going 3D.  The first layer is semi-reflective, which allows the second beam to reach the second layer, which is fully reflective. The disk is made by bonding together two 0.6 mm thick substrates using transparent (with no internal defects or bubbles) UV-cured (UV = ultra-violet) lacquer. This disk design allows almost twice as much data to be stored as DVD-5.  Labels are printed on the other side of the disk conventionally.

Page [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

 Back to Top