HDTV Goes Blue?
According to the group, the Blu-ray Disc technology 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 405mm blue-violet laser. The companies that established the basic specifications for the Blu-ray Disc are: Hitachi, LG Electronics, Matsushita Electric Industrial, Pioneer, Philips Electronics, Samsung Electronics, Sharp, Sony, and Thomson Multimedia.
In addition to actively promoting the new format throughout the industry, the nine companies say they plan to begin licensing the format as soon as specifications are completed in the spring of 2002. Major obstacles remain, however, as Hollywood struggles with the CE industry over copyright and connection technology for high resolution content.
By employing a short-wavelength blue-violet laser, the group says, the Blu-ray Disc format successfully minimizes its beam spot size by .85, making the numerical aperture (NA) on a field lens that converges the laser. 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 better disc readout and an increased recording density." The Blu-ray Disc's tracking pitch is also said to be reduced to 0.32µm, almost half of that of a regular DVD, achieving up to 27GB of high-density recording on a single-sided disc.
The companies add that because the Blu-ray Disc utilizes standard "MPEG-2 Transport Stream" compression technology, which is 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 [to record] other data simultaneously with video data if they are received together," says the group. In addition, the new technology sports the adoption of a unique ID written on each Blu-ray Disc to "realize high quality copyright protection functions."
The nine companies involved in the announcement say they are all planning to develop products that take full advantage of Blu-ray Disc's large capacity and high-speed data transfer rate. They say they also aim to further enhance the appeal of the new format by developing a larger capacity, perhaps over 30GB on a single-sided single-layer disc and over 50GB on a single-sided double-layer disc. As a result, they say, adoption of the Blu-ray Disc is being considered in a variety of applications, including PC data storage and high definition video software.