Blue Ray Disc

Blu-ray Disc

The Blu-ray Disc is an optical disc format which currently offers one of the highest data storage capacities so far, making it possible to store very large amounts of digital information, such as high-definition video, on a single disc.

The Blu-ray Disc Format: an Overview

Blu-ray Disc, or BD, is the term coined to refer to the next generation in optical disc formats.  This technology was developed in order to make the possibility of recording, playback, rewriting, and storage of very large amounts of digital information possible and practical, both for the industry and for the average consumer.  The coinage came from the type of laser on which the technology is based upon; a blue-violet laser for reading and writing information.  

Blue optical ray was contracted into the term Blu-ray, and the omission of the 'e' in 'blue' was intentional, for purposes involving trademark rights, since everyday words such as 'blue' are prohibited from intellectual ownership.  The technology was developed through the Blu-ray Disc Association, which is composed of the industry's foremost manufacturers of media, consumer electronics, and personal computers, with a current membership of 180 companies worldwide.

The Blu-ray Disc is touted to be the replacement to the current popular format, the DVD, since the industry, particularly the entertainment industry, is generally moving over towards high-definition video releases; video in high-definition requires huge amounts of data to be stored in media with very large storage capacities, a requirement which cannot be sufficed by the DVD.  A single-layered Blu-ray Disc can store up to five times the amount of data which a DVD can accommodate, thereby making the former the feasible and practical choice for such purposes.

The main use of the Blu-ray Disc for the average consumer is in its offering of very high quality video and audio, as the format uses sophisticated audio and video codec types; this, in combination with the format's immense storage capacity, can provide the consumer the practicality of the high-definition entertainment experience, right in the comfort of the home.  Blu-ray Discs are the next progressive step in the attempt to sate the consumer's need for unparalleled entertainment at an affordable cost.

Characteristics of the Format

Blu-ray Disc technology differs from DVD and CD formats because it uses a laser of a shorter wavelength.  The blue-violet laser reads or writes on the disc's surface at a wavelength of about 405nm, compared with the red or near infrared laser which are used by DVD and CD formats, with respective wavelengths of 650nm and 750nm. 

Optical discs are read or written on with a laser, on minute focus areas or spots, and is dependent on at least three factors: the wavelength of the laser light used, the numerical aperture provided by the lens for focusing the laser, and the data encoding technology employed to maximize storage capacity.  Blu-ray technology uses a laser of shorter wavelength, and an aperture which makes the surface layer 'thinner' as consequence, in order to prevent unnecessary optical effects during the reading and writing of data. 

These two improvements afford the laser the capability of focusing onto a smaller spot on the disc's surface, and allowing more data to be stored on a disc which has roughly the same physical size as that of a DVD or VCD.  Blu-ray discs also feature advancements in data encoding techniques, which enables even more data to be stored on the disc.  As a result, a single-layered Blu-ray disc can accommodate a maximum of 25 Gigabytes of information, while a dual-layered disc can hold up to 50 Gigabytes, storage capacities which exceed that of the DVD by about five times the amount. 

As if this wasn't enough, the developers of the technology provided a measure for the format to support discs of multiple layers, allowing the maximum storage capacity an upgrade of up to 200 Gigabytes of information on a single multi-layered disc (each layer may contain about 25 Gigabytes of information as a maximum capacity), thus ensuring that the Blu-ray Disc will remain a viable media format in the future.

Advantages of Blu-ray Technology

The Blu-ray Disc is indeed superior to the DVD in several ways.  The information which is stored or read from the surface of a Blu-ray disc is placed over a layer of polycarbonate material of about 1.1 mm thickness.  With the information placed on top, problems concerning disc readability or writability are efficiently eliminated.  Also, since the recording layer of the disc is appreciatively much closer to the reading mechanism's objective lens, any difficulties as caused by disc tilt is prevented. 

In order to protect the information which is stored much closer to the disc's surface from wear as caused by inevitable scratches and mishandling, a hard, top-layer coating is added as a final measure of maintaining the disc's durability.  This manufacturing process is more cost-effective compared to that involved with the DVD, which is produced by molding two separate discs, placing the recording layer on the surface of one of them, and the two separate discs are then glued together. 

With Blu-ray Discs, the recording layer is injection-molded on just a single 1.1mm disc, reducing production costs significantly.  The addition of the final protection layer offsets the savings from the previous procedure, resulting in an end manufacturing cost which is roughly the same as that of a regular DVD.  Blu-ray discs can also be recorded with a faster pace than current DVDs, since the superior data transfer rate of the former (36 megabits/second) is more than three times the speed of the latter (10 megabits/second). 

Blu-ray discs can be recorded with 25 Gigabytes of information, in a relatively short period of less than two hours.    To say that Blu-ray technology is revolutionary and superior is an understatement; it offers storage capacities and recording speeds which are larger and faster than the current standard format, this being done with an accompanying end cost which is very affordable, both for the manufacturer and the consumer.

Features and Types of the Blu-ray Disc and Player Format

Blu-ray Discs are also provided with an additional protective measure against video piracy or violations of copyright.  These are produced with an equipped secure encryption system, which is a more complex and unique identification device, protecting it from such mentioned infractions.  They may also be encoded with region codes, a measure which restricts them to a certain area for playback.  This means that the Blu-ray players which are sold in a specific region may only play Blu-ray discs which are specifically encoded for that particular region. 

This affords the motion picture companies control of the different aspects of a film release to suit the region, such as content and price.  Blu-ray discs can also be made without region coding, enabling playback on all Blu-ray players.  In order to keep the transition from DVD to Blu-ray as smooth as possible, the industry's leading electronic companies have shown support by putting out products which are backward compatible, able to read and write Blu-ray discs, Compact discs, and DVDs with the use of a multipurpose optical head; since Blu-ray titles are, at present, scarce, and may take some time to flourish, consumers will have the convenience of playing DVD titles on the same Blu-ray disc player. 

Recent versions of the product even provide an enhancement of DVDs, by upscaling the resolution to 1080p/1080i, so the videos in DVD format will have a digital retouch, and will look sharper and clearer than ever.  Blu-ray technology is also offering a variety of formats to support data storage needs, including BD-Rom, which is a read-only format used for the distribution of software, movies, and games; BD-R, a recordable format for recording high-definition video, and also for PC information storage; and BD-RE, a rewritable format for the same purposes as those with BD-R, except that data can be written over the disc multiple times.

Competitors and Availability

At present, there is mounting industry support for Blu-ray technology, even with the presence of a rival format, in the form of HD-DVD, an optical format which employs similar technology.  Actually, as of this writing, Blu-ray and DVD are not alone in the industry, as several other companies are putting out formats which intend to rival Blu-ray in terms of data storage capacity and affordability.  HD-DVD-9, which is developed by Warner Bros. Pictures, employs a superior compression rate, allowing up to two hours of HD video to be written on a standard, single-sided DVD. 

Forward Versatile Disc, which is an upgrade of the DVD, also affords for more storage capacity on a DVD (up to 5.4 Gigabytes for a single-sided DVD, and up to 9.8 Gigabytes for a double-sided DVD.  Another variant is the Enhanced Video Disc, introduced by China and affords for storage of HD video on a single disc.  Probably the biggest threat to Blu-ray technology is that which is currently being developed by Pioneer, which is rumored to accommodate as much as 500 Gigabytes of information, with the use of a laser wavelength which is far shorter than that employed by Blu-ray – ultraviolet.  Those who are considering an investment in Blu-ray players and discs should have no reason for worries, however, as the prospects for the technology is promising for years to come. 

Since it is a relatively new product, initial prices are quite steep; but these are bound to fall as mass production and industry acceptance is established.  At present, there are a lot of products slated for launch which is related to Blu-ray, including media, players, writers, recorders and drives.  Blu-ray players and discs are currently very available in the United States and Canada, from electronic giants like Pioneer, Samsung, Philips, Panasonic, and Sony, as well as from Sharp and LG.  The first wave of Blu-ray technology is now also available in most European countries.  Prices range depending on the features of the player, and the storage capacity and function of the disc.