Blue Ray Disc- Engineering Seminar Paper

ABSTRACT

            Blu-ray, also known as Blu-ray Disc (BD) is the name of a next-generation optical disc video recording format jointly developed by nine leading consumer electronics companies. The format was developed to enable recording, rewriting and playback of high-definition video (HDTV). Blu-ray makes it possible to record over 2 hours of digital high-definition video (HDTV) or more than 13 hours of standard-definition video (SDTV/VHS picture quality) on a 27GB disc. There are also plans for higher capacity discs that are expected to hold up to 50GB of data.

            The Blu-ray Disc technology can store sound and video while maintaining high quality and also access the stored content in an easy-to-use way. Adoption of the Blu-ray Disc in a variety of applications including PC data storage and high definition video software is being considered.

Introduction

            Nine leading companies today announced that they have jointly established the basic specifications for a next generation large capacity optical disc video recording format called "Blu-ray Disc". The Blu-ray Disc enables the recording, rewriting and play back of up to 27 gigabytes (GB) of data on a single sided single layer 12cm CD/DVD size disc using a 405nm blue-violet laser.

            By employing a short wavelength blue violet laser, the Blu-ray Disc successfully minimizes its beam spot size by making the numerical aperture (NA) on a field lens that converges the laser 0.85. In addition, by using a disc structure with a 0.1mm optical transmittance protection layer, the Blu-ray Disc diminishes aberration caused by disc tilt. This also allows for disc better readout and an increased recording density. The Blu-ray Disc's tracking pitch is reduced to 0.32um, almost half of that of a regular DVD, achieving up to 27 GB high-density recording on a single sided disc.

            Because the Blu-ray Disc utilizes global standard "MPEG-2 Transport Stream" compression technology highly compatible with digital broadcasting for video recording, a wide range of content can be recorded. It is possible for the Blu-ray Disc to record digital high definition broadcasting while maintaining high quality and other data simultaneously with video data if they are received together. In addition, the adoption of a unique ID written on a Blu-ray Disc realizes high quality copyright protection functions.

            The Blu-ray Disc is a technology platform that can store sound and video while maintaining high quality and also access the stored content in an easy-to-use way. This will be important in the coming broadband era as content distribution becomes increasingly diversified. The nine companies involved in the announcement will respectively develop products that take full advantage of Blu-ray Disc's large capacity and high-speed data transfer rate. They are also aiming to further enhance the appeal of the new format through developing a larger capacity, such as over 30GB on a single sided single layer disc and over 50GB on a single sided double layer disc. Adoption of the Blu-ray Disc in a variety of applications including PC data storage and high definition video software is being considered.

Concept of the format establishment :

Ø    To realize the large capacity with 12cm disc

- More than 2-hour high definition video recording

- High capacity of more than 4-hour recording by double layer technology.

Ø    To cope with digital broadcasting

- High compatibility with digital broadcasting

- To prevent illegitimate duplication of contents

Ø    To enhance the Blu-ray Disc world

- Adoption of the Blu-ray Disc in variety of media and applications

Main Features of physical format:

Ø    Large recording capacity up to 27GB:

            By adopting a 405nm blue-violet semiconductor laser, with a 0.85NA field lens and a 0.1mm 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)

Ø     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

Ø     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.

Ø    Recording format:

            Like the DVD, the Blu-ray disc uses phase change recording. This must be good news for those who plan to make the new format compatible with its wildly popular predecessor. This recording format will also makes a two-sided disc easily realizable because both writing and reading can be executed by a single pickup.

Ø    Multiplexing:

            Blu-ray disc utilizes global standards like MPEG-2 Transport Stream compression technology for video and audio multiplexing. This makes it possible for a Blu-ray Disc to record high definition broadcasting and other data simultaneously with video data if they are received together. Data captured on a video camera while recording images being broadcast on TV can also be edited simultaneously.

Main Features Of Logical format :

Ø    Highly compatible with digital broadcasting  :

            MPEG2 transport stream compression technology for video recording can record digital broadcasting including HDTV while maintaining its original picture quality.

Ø    Best data structure for disc recording

            Achieving improvement of searching, easy editing functions and play a list playback functions by adapting logical data structure making the best use of

random accessing.

Ø    File system for HDTV real time recording

            Adapting the file system which can achieve high bit rate recording and playback of HDTV and best use of disc space

The Blue Laser

            A blue laser operates in the blue range of the light spectrum, ranging from about 405nm to 470nm. Most blue laser diodes use indium gallium nitride as the material to create the laser light, although the amount of indium included in the material varies. (Some blue laser diodes use no indium.) Some manufacturers create blue LEDs (light-emitting diodes), which create light in a manner similar to lasers with silicon carbide.

            Blue laser beams have a smaller spot size and are more precise than red laser beams, which lets data on blue laser optical storage discs be stored more densely. The spot size of a laser beam is one determining factor, along with the materials in the optical disc and the way the laser is applied to the disc, in the size of the pits the laser makes on an optical disc. Laser beams with larger spot sizes typically create larger pits than those with smaller pit sizes. Blue lasers are desirable because blue light has the shortest wavelength among visible light.        

A blue laser operates at a shorter wavelength of about 405nm than a red laser at about 650nm. A nanometer (nm) is one-billionth of a meter, one-millionth of a millimeter, and one-thousandth of a micron. One inch is equal to about 25.4 million nanometers. A human hair is about 50,000nm wide.

Putting Blue Lasers to Work

            Blue lasers could appear in a variety of business applications, including high-density DVDs, laser printers, and lighting situations.

 HD DVDs : HD (high-definition) DVDs using blue laser light could lead to five or six  times the storage capacity possible using red laser light on a DVD. Blue laser light could create HD CDs, too.

            Because blue lasers can increase the capacity of optical discs by five-fold or more, they give manufacturers a few options for their digital files. Manufacturers could choose to burn additional data onto the disc while keeping the same digital quality, potentially making CDs containing 50 to 75 songs. Manufacturers also could choose to use blue laser to increase the quality level of the video or audio recording. Keep in mind that nearly all DVDs using the MPEG-2 standard automatically contain some compression of the video file, which allows the file to fit on the disc. With an HD DVD, manufacturers could choose to use no compression on the video file, which should improve file quality.

Light bulbs : With green and red lasers already available, development of a blue laser would be the final piece of the laser puzzle among primary colors. By using all three colors of lasers, a researcher could create a device that would mix the laser light and create white light, which, at some point, could replace the common light bulb. If you combine red, green, and blue laser light, you can produce light with greater brilliance and greater efficiency than currently is available with fluorescent lights.

            Creating LEDs in this manner can be of particular help in areas where light bulbs are expensive and difficult to replace. An LED can burn for several times as long as a light bulb for about one-fourth the operating cost because most of the LED’s energy is involved in creating light, rather than creating heat energy. Traditional light bulbs create a lot of heat along with the light.

            LEDs already are used in many traffic lights, where traditional bulbs usually last less than one year, can be tough to see in sunlight, and fail suddenly. LEDs in a traffic light should last at least five years, remain highly visible in sunlight, and gradually fade in intensity rather than failing suddenly.

Medicine : Scientists already are experimenting with blue lasers in discovering certain types of cancer. Using an endoscope, researchers have had some success finding tumors using a blue laser light inside the patient’s stomach and intestinal tract.

Printing : Laser printers using blue laser light would be smaller and more precise than today’s laser printers, which use red laser light. Because of blue laser light’s smaller wavelength, the laser mechanism inside a printer that uses blue laser light could be smaller, leading to smaller printers. Print resolution using blue lasers would be at least double that of today’s top laser printers, too; some researchers estimate resolution as sharp as 2,400dpi in a blue laser printer. Blue laser could play a role in full-color scanners and fax machines, too.

Security : After the terrorist attacks of Sept. 11, fears have increased over additional attacks using biological or chemical weapons. However, blue laser light causes some chemical and biological agents to give off light, even though those agents are invisible to the naked eye, which might let security screening personnel spot a biological agent during a routine search or as the agent comes through customs.

The Blu-ray Impact

            Blu-ray is expected to challenge DVD's run as the fastest selling consumer-electronics item in history. If that happens, the impact would be too big for the major players to discount. For example, the number of films sold on DVD more than doubled last year to over 37 million. In addition, almost 2.4 million DVD players were bought in the past year. As Blu-ray is not compatible with DVD, its success could upset the applecart of many players. If the new format turns out to be much popular, the demand for DVD players could come down drastically. Not withstanding the challenge to DVD makers, the new format is seen as a big step in the quest for systems offering higher data storage. It is expected to open up new opportunities for broadcasting industry. Recording of high-definition television video—an application in which more than 10GB of storage space is filled up with just one hour of video—will get a major boost. Conversely, the format could take advantage of the spread of high-definition television. As Blu-ray Disc uses MPEG-2 Transport Stream compression technology, recording for digital broadcasting would become easier. Its adoption will grow in the broadband era as it offers a technology platform to manage stored content. But the real action will begin when the companies involved develop products that take full advantage of Blu-ray Disc's large capacity and high-speed data transfer rate. As that happens, Blu-ray will move beyond being a recording tool to a variety of applications. Adoption of Blu-ray Disc in PC data storage is already being considered.

Comparison of Storage Technologies

            While current optical disc technologies such as CD, DVD, DVD-R, DVD+R, DVD-RW and DVD+RW use a red laser to read and write data, the new format uses a blue laser instead, hence the name Blu-ray. The benefit of using a blue laser is that it has a shorter wavelength (405 nanometer) than a red laser (650 nanometer), which means that it's possible to focus the laser beam with even greater precision. This allows data to be packed more tightly on the disc and makes it possible to fit more data on the same size disc. Despite the different type of lasers used, Blu-ray Disc Recorders will be made compatible with current red-laser technologies and allow playback of CDs and DVDs.

      The following diagram shows the comparison between different storage Technologies.

How does Blu-ray disc work?

History of Technology

1.                  The challenge to write more information on disk

2.                  Shiju Nakamura is credited with inventing the blue diode laser and

            blue, green, and white LEDs.

3.                  Nakamura was working at Nichia Chemical Industries in Japan

            when he developed the blue laser in 1995.

Description of how this technology works.

            Blue lasers have a wavelength of 405 nanometers, shorter than that of red lasers, which have a wavelength of around 650 nanometers and are used for reading and writing DVD and CD discs. The shorter wavelength means that the laser can register smaller dots on a disc and more data can be stored. As a result, blue laser technology has been adopted for the development of next-generation optical discs.

1. Using double infrared frequency to create the wavelength for blue light.

2. A blue laser operates in the blue range of the light spectrum, ranging from about 405nm to 470nm.

3. Most blue laser diodes use indium gallium nitride as the material to create the laser light.

4. Blue laser beams have a smaller spot size and are more precise than red laser beams, which lets data on blue laser optical storage discs be stored more densely.

5. The spot size of a laser beam is one determining factor, along with the materials in the optical disc and the way the laser is applied to the disc, in the size of the pits the laser makes on an optical disc.

6. Laser beams with larger spot sizes typically create larger pits than those with smaller pit sizes.

Future Developments

            Despite the impending tug-of war, the industry is excited about the future prospects of this technological innovation. The industry is of the view that Blu-ray has the potential to replicate, if not better, the DVD success story. The expected upswing in high-definition television adoption and broadband implementation could act as the catalyst. Aware that the recession in economies across the globe could come in the way of high-definition television broadband penetration, major players are exploring the ways to make Blu-ray compatible with DVDs. Cost can dampen the sales in the first year. Owing to the patent and the technology involved, Blu-ray is likely to cost more than DVDs. But sooner than later, it will move towards commodity pricing. Once that happens, Blu-ray holds the promise to steal a march over its immediate predecessor.

Conclusion

            In conclusion the Blue-ray Disc is a technology platform that can store sound and video while maintaining high quality and also access the stored content in an easy-to-use way.  Blue lasers have a shorter wavelength, which means the laser beam can be focused onto a smaller area of the disc surface. In turn, this means less real estate is needed to store one bit of data, and so more data can be stored on a disc.  This will be important in the coming broadband era as content distribution becomes increasingly diversified.  Companies involved in the development will respectively make products that take full advantage of Blue-ray Disc's large capacity and high-speed data transfer rate. They are also aiming to further enhance the appeal of the new format through developing a larger capacity, such as over 30GB on a single sided single layer disc and over 50GB on a single sided double layer disc. Adoption of the Blue-ray Disc in a variety of applications including PC data storage and high definition video software is also being considered.  There is a lot of talk about blue-laser-based systems being focused around high-definition television, which has heavy data needs. But Blue-ray Disc groups are also considering development of write-once and read-only formats for use with PCs.

            Prototype blue-laser-based optical disc systems have been around for more than a year. However, one problem has hampered development of commercial systems: cost. A sample blue-laser diode currently costs around $1000, making consumer products based on the parts unrealistic. However, Nichia, the major source for blue lasers, is expected to begin commercial production this year and the price of a blue-laser diode is expected to tumble once the company begins turning them out in volume.  The DVD forum may or may not invite the blue-ray light into is era but the 27GB disc is not far off in practically disturbing the DVD wave.