Laser and Optical Disc

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1. Introduction
Blu-ray is a new optical disc standard based on the use of a blue laser rather than the red laser of today’s DVD players. The standard, developed collaboratively by Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and Thomson, threatens to make current DVD players obsolete. It is not clear whether new Blu-ray players might include both kinds of lasers in order to be able to read current CD and DVD formats.

The new standard, developed jointly in order to avoid competing standards, is also being touted as the replacement for writable DVDs The blue laser has a 405 nanometer (nm) wavelength that can focus more tightly than the red lasers used for writable DVD and as a consequence, write much more data in the same 12 centimeter space Like the rewritable DVD formats, Blu-ray uses phase change technology to enable repeated writing to the disc.

Blu-ray’s storage capacity is enough to store a continuous backup copy of most people’s hard drives on a single disc. The first products will have a 27 gigabyte (GB) single-sided capacity, 50 GB on dual-layer discs. Data streams at 36 megabytes per second (Mbps), fast enough for high quality video recording Single-sided Blu-ray discs can store up to 13 hours of standard video data, compared to single-sided DVD’s 133 minutes. People are referring to Blu-ray as the next generation DVD, although according to Chris Buma, a spokesman from Philips (quoted in New Scientist) “Except for the size of the disc, everything is different.”

Blu-ray discs will not play on current CD and DVD players, because they lack the blue-violet laser required to read them. If the appropriate lasers are included, Blu-ray players will be able to play the other two formats. However, because it would be considerably more expensive, most manufacturers may not make their players backward compatible. Panasonic, Philips, and Sony have demonstrated prototypes of the new systems.

Blu-ray Disc Key Characteristics
Large recording capacity up to 27GB
By adopting a 405nm blue-violet semiconductor laser, with a 0.85NA field lens and a 0.1 mm. optical transmittance protection disc layer structure, it can record up to 27GB video data on a single sided 12cm phase change disc. It can record over 2 hours of digital high definition video and more than 13 hours of standard TV broadcasting (VHS/standard definition picture quality, 3.8Mbps) High-speed data transfer rate 36Mbps

It is possible for the Blu-ray Disc to record digital high definition broadcasts or high definition images from a digital video camera while maintaining the original picture quality. In addition, by fully utilizing an optical disc’s random accessing functions, it is possible to easily edit video data captured on a video camera or play back pre-recorded video on the disc while simultaneously recording images being broadcast on TV. Easy to use disc cartridge

An easy to use optical disc cartridge protects the optical disc’s recording and playback phase from dust and fingerprints. Blue Laser
A blue laser is a laser (pronounced LAY-zer) with a shorter wavelength than the red laser used in today’s compact disc and laser printer technologies and the ability to store and read two to four times the amount of data. When available in the marketplace, personal computer users may be able to buy a laser printer with a resolution up to 2400 pixels or dots per inch at an affordable price. The same technology in CD and DVD players will provide a dramatic breakthrough in storage capability without an increase in device size.

A laser (an acronym for “light amplification by stimulated emission of radiation”) is a coherent (meaning all one wavelength, unlike ordinary light which shower on us in many wavelengths) and focused beam of photons or particles of light. The photo are produced as the result of a chemical reaction between special materials and then focused into a...
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