LG CED-8081B Service Manual page 32

5. Writing Process of CD-R Disc
Incident
Laser
Power
(Read)
Laser
Spot
Recorded
Mark
Reflected
Light
Signal
6. Writing process of CD-RW Disc
Crystal phase
quenching
gradual cooling
Erased state
(higher reflectivity)
18
(Write)
(Read)
a b c d e f g
a
b
c
d
e
f
a b c d e f g
Amorphous
Melting/
Heating/
Recorded state
(lower reflectivity)
Laser Spot
Position
(Time)
Reflected
Light
Signal
g
Laser Spot
Position
(Time)
Write Power
Erase Power
Read Power
Groove
Below "ORP"– Mark Too Short
At Optimum Record Power ("ORP")
Above "ORP" – Mark Too Long
Time
Crystal
Amorphous