LG Electronics GSA-4167B Disc Materials, CD-ROM disc, CD-R disc, Pigment, Reflective Layer, Color

3. Disc Materials

1)CD-ROM disc

•It is composed of Silver _ colored aluminum plate and Reflective layer.

•Groove (Pit) of aluminum plate make a track.

•Laser wavelength : 780 nm, Laser Power (Read): 0.5mW

•Signal is detected by the difference of reflective beam

intensity between “pit” and “Land” on the disc.

Label Printing

Protective Layer

Reflective Layer

Substrate (Polycarbonate)

Pit

Laser Beam

2)CD-R disc

•It is so-called WORM (Write Once Read Many) CD.

•It is composed of polycarbonate layer, Organic dye layer, Reflective layer, and Protective layer.Gold/Silver Reflective layer is used to enhance the reflectivity

•According to the kinds of Organic dye layer, it is divided by Green CD, Gold CD, Blue CD.

•Laser Wavelength : 780 nm, Laser Power (read) : 0.7 mW

•Recording Power : 8x(14~20mW), 16x(25~35mW)

•When some part of dye layer is exposed to laser heat, it’s color changs black.Therefore, writing and reading is enabled by the difference of reflectivity between changed part and unchanged part.

•Polycarbonate layer has Pre_Groove which make a Track.

Pigment	Reflective Layer	Color
Phtalocyanine	Gold/Silver	Yellow/White
Cyanine	Gold/Silver	Dark Green/Bright Green
Azo	Gold/Silver	Dark Blue

Label Printing

Protective Layer

Reflective Layer

Organic Dye Layer

Substrate (Polycarbonate)

Laser Beam Groove

21