Iranian Company Takes Advantage of Nanocoating to Improve DVD Quality
Nanocoating is an ultra-thin layer or a chemical structure that is built upon surfaces by a variety of methods. Typically, nanocoating is used to impart a particular chemical or physical function to a surface.
The company has produced a 120 mm digital versatile disc (DVD9) with a capacity of 9 GB using nanometer coating.
The use of nanocoating has improved the quality of the product.
Compact disks (CDs) and DVDs are used in data storage, in which the information is stored by means of a laser and creating small holes in the spiral tracks on its surface.
The data is coded as zeros and ones (binary) on the disk and read by a weaker laser and an electric eye (photocell) in optical disk drives.
There are different types of discs, including CD, DVD, and DVD9, which are categorized based on the storage capacity for data.
These disks are similar to each other in dimension, and the production process and the type of materials used are almost the same.
A DVD is usually made of four layers and has a thickness of 1.2 mm. In order to increase the storage capacity of DVDs, various methods are used.
One of the methods is to change the number of DVD layers. Accordingly, there are three types of DVDs: single-sided-single-layer (4.7 GB), single-sided-double-layer (8.5 GB), and double-sided-double-layer (17 GB).
DVD9 is composed of two layers, active and dummy, the active layer is metalized at approximately 15 nm and the dummy layer is metalized at 42 nm.
The capacity of DVD9 is twice the capacity of other DVDs and it has information on both layers so that the operators first read the active layer information at one frequency and then read the dummy layer information by changing the frequency.
Another method for increasing the DVD capacity is to apply a nanometer coating on the surface of the disk, which improves features such as light reflection and readability.
The DVD produced by the Iranian company has a coating with a thickness of less than 70 nanometers, which is made of polycarbonate. These disks have a capacity of 8.5 GB.
The CDs produced by the company have a coating with a thickness of less than 100 nanometers and a capacity of 700 MB.
Applying a nanocoating using the sputtering method on the surface of the CD has improved the quality of the product. Also, reducing the thickness of the coating applied on the surface of the disk has decreased its price.
The national document on promoting the application of nanotechnology has outlined the path to achieving the major goals of the development of nanotechnology in the country.
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