Fostex CR200 Service Manual page 6

CR200
1-4. CD-R Disc Structure and Bubbling Process
The materials of CD-R disc consists of label,
protective layer, reflective layer, organic dye
layer and transparent substrate.
During recording, the laser is tracing the wobbled groove. When a pit is to be recorded, the laser fires off a high power beam
and the organic dye will become black and deformed. This is the way a Ònon-reflectiveÓ part is created. When a groove is
to be recorded, the laser is not fired and the high-reflective surface is maintained. If the data word contains successive the
same information (e.g. 111 or 000), the pit will be continuous. When the data word contains changes, the pit - groove status
will also change.
• Recording Principle
• Playback Principle
1-5. Finalize
In order to be playable on an ordinal CD-player, the CD-R disc must have a corresponding data for TOC (Table Of Contents).
This area is not used until all the recording is completed. Instead, a special area called PMA (Program Memory Area) is used.
When the disk is full or all the recording is completed, the disk can be finalized. This means that the temporary information
in the PMA is checked and transferred to TOC. Now the disk is playable on an ordinal CD player but it will not be recordable
any more.
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Fig. 4 Cross Section of CD-R disc
A high power laser beam is shot.
NO PITS
A low power laser beam is shot
and high reflectance is obtained.
Fig. 5 Recording & Playback Principle
Label
UV protective layer
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
Refective layer
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
Organic dye layer
Transparent
substrate
Laser beam
Organic dye becomes black
and pit is created.
ON PITS
A low power laser beam is shot
and only low reflectance is obtained.
Land
Groove