Optical Disc Capacities/Layers: CD/DVD and Blu-ray

CD/DVD

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1. Polycarbonate Substrate: This is the bottom layer of the CD and serves as the foundation. It provides structural support to the disc.

2. Reflective Layer: This layer reflects the laser beam used to read the data encoded on the disc.

3. Data Layer: The data layer contains the encoded information stored in the form of pits and lands.

4. Protective Layer: This layer protects the data from scratches, dust, and other potential damage.

​4 Layers

Polycarbonate Substrate: This layer provides structural support to the disc.

Dielectric Layer: This layer helps to reduce reflections from the reflective layer and improves the focusing of the laser beam, contributing to better data reading accuracy.
Reflective Layer: This layer reflects the blue laser beam used to read the data encoded on the disc. The blue laser has a shorter wavelength than the red laser used in DVDs and CDs, allowing for higher data density and storage capacity.

Data Layer(s): Single-layer Blu-ray Discs have one data layer, while dual-layer Blu-ray Discs have two. Each data layer contains encoded information stored in the form of pits and lands.

Hardcoat Protection Layer: This layer provides enhanced durability and resistance to scratches, fingerprints, and other physical damage.

BLUE-RAY LAYERS

5 layers

​CD (Compact Disc) (650mb-795mb): 

Standard CD: Can hold up to 700 MB of data. 

CD-ROM/XA: Holds up to 795 MB of data. 

CD-R: Holds up to 700 MB of data. 

CD-RW: Holds up to 700 MB of data. 

​DVD (Digital Versatile Disc) (4.7gb-17gb):

DVD-5: Single-sided, single-layer DVD holds up to 4.7 GB of data. 

DVD-9: Single-sided, dual-layer DVD holds up to 8.5 GB of data. 

DVD-10: Double-sided, single-layer DVD holds up to 9.4 GB of data. 

DVD-18: Double-sided, dual-layer DVD holds up to 17 GB of data. 

Blu-ray Disc (25gb-128gb): 

Single-layer Blu-ray: Holds up to 25 GB of data. 

Dual-layer Blu-ray: Holds up to 50 GB of data. 

Triple-layer Blu-ray (BDXL): Holds up to 100 GB of data (in rewritable format). 

Quadruple-layer Blu-ray (BDXL): Holds up to 128 GB of data (in write-once format). 

Quintuple-layer Blu-ray (BDXL): Holds up to 128 GB of data (in rewritable format). 

Optical Disc Capacities: CD/DVD and Blu-ray

- compatibility for the older format
+ compatibility for newer format
-+ compatibility for both newer and older
RW = Rewritable