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Structure and Mechanism of recording and playback

Recording format using organic dye material
(DVD-R and DVD+R)
The format that records data through the creation of recorded marks by changing the organic dye material with a laser beam.

-Disc structure
DVD-R/DVD+R Conceptual drawing
< Conceptual drawing >

-Recording principles
[ Recording ]
Recording is done by changing the organic dye layer and the substrate with a laser. When a strong laser is applied to a disc, the temperature of the organic dye material goes up, the dye is decomposed. At this time, a durable pit is created as is the case with a DVD-ROM.

[ Playback ]
Signals are read with the differences of the reflection of a laser from pits.
Conceptual drawing
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Recording format using phase-change recording material
(DVD-RW and DVD+RW)
Data is recorded by changing the recording layer from the amorphous status to the crystalline status, and played back by reading the difference of the reflection coefficient.
* Amorphous: Non-crystalline

-Disc structure
DVD-RW/DVD+RW Conceptual drawing
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-Recording principles
[ Recording ]
When a high-power laser is applied to the recording material, it melts and then becomes amorphous with a low reflection coefficient when it quickly cools off. When a mid-power laser is applied to heat gradually the recording material and then gradually cools it off, it becomes crystal with a high reflection coefficient.

[ Playback ]
A low-power laser is used for playback. The amount of reflected light depends on the status (amorphous or crystalline) of the recording material. This is detected by an optical sensor.
Recording principles

Conceptual drawing

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