Optical recording looks bright: high-capacity, rewritable DVD is poised to be the future of optical storage. (Tape/Disk/Optical Storage).

DVD is one of the few technologies that has lived up to--and even surpassed-- the initial hype. The rapid acceptance of DVD as the new standard for home video players is spurring the next growth area for this technology: recordable DVD. In the consumer, broadcast, and data storage markets, recordable-DVD formats are poised to duplicate the success of the read-only video format. The rapid reduction in hardware costs, the emergence of industry-wide standards from the DVD Forum, and the insatiable demand for increased data-storage capacity and digital entertainment content have combined to make recordable DVD the format of choice for a wide range of applications.

DVD sales are growing at unprecedented rates. According to the DVD Entertainment Group, DVD player sales in North America have grown from approximately 9.8 million in 2000 to an estimated 20 million in 2002. The group estimates that nearly half of all U.S. homes will have DVD capability by the end of this year. Santa Clara Consulting Group (SCCG) projects the market for recordable DVD hardware will grow to more than 1.6 million units this year, with demand increasing dramatically for both DVD video recorders and DYD data drives. And Techno Systems Research estimates that by the end of 2002, the installed base of recordable DVD drives will grow to 4.9 million units.

The projected growth of recordable DVD is likely to come from three key areas: DVD-based personal video recorders, as a replacement for videotape in consumer and professional video production, and in computer data storage applications.

Recordable DVD is well-positioned to replace videotape for home-recording applications as the center of the next wave of personal video recorders (PVRs). First-generation PVRs such as TiVo and Replay use hard-disk storage, but offer no convenient way to archive content once the disk is filled up. DVD-based PVRs address that limitation, offering recordable formats that can be rewritten, just as with disk-based PVRs, and write-once formats that can be archived to preserve important programs.

Price reductions in digital camcorders and PC-based recordable DVD hardware, along with the arrival of easy-to-use editing and production software, has made digital production simple and affordable for both personal and business applications. Recordable-DVD discs are playable on virtually all DVD video players, enabling consumers to easily move their digital productions from the camcorder to the PC to the DVD video player. The arrival of the new mini DVD (8cm) DVD-R and DVD-RAM discs, developed for use in new digital camcorders, streamlines the digital editing process by eliminating the need to transfer video footage from digital tape into a computer-based editing system.

DVD recordable technology is also gaining popularity as a removable media data storage device. In fact, SCCG projects that more than 80% of the recordable DVD units sold this year will be data drives. In addition to conventional data backup and archiving storage applications, DVD discs also provide data portability and data distribution for contentrich applications such as digital video clips embedded in PowerPoint presentations.

To 100 Gigabytes and Beyond

While the 4.7GB capacity of a single-sided, single-layer DVD is a huge improvement compared to the 700 MB on a CD, it has already been deemed insufficient for the next generation of data storage and high-definition video applications. With 40GB and 60GB hard disks common on new PCs, DVD needs a capacity boost to keep pace as a viable backup medium. Additionally, DVD is not compatible with, nor does it have adequate capacity for, new high-definition television formats. A great appeal of DVD is that more than 90% of Hollywood movies can fit on a single 4.7GB disc; that is not the case with HD video. So as the first generation of record- able DVD technology is still gaining market momentum, the development is already underway on future generations that will expand DVD capacity to 100GB per disc by 2006.

To reach that objective, recordable DVD media will experience improvements in three critical areas: advanced stamper technology, advanced recording materials, and advanced molding technology. These media improvements will be accompanied by a transition to a new generation of laser technology. First, advanced stamper technology will enable higher track densities in next-generation DVD media. The stamper machines that actually produce the DVD discs will be modified to create smaller tracks on the disc, generating a capacity boost with higher track densities.

The increased track density will be complemented with higher bit densities made possible by advanced, high-density recording materials. New polymer dyes are being developed for the write-once DVD formats that will enable the laser recording of narrower and shallower pits on the disc, supporting increased bit densities and the potential for multiple layers. Similarly, new metal alloys will be required for phase-change-based rewritable media.

With increased track and bit densities, future DVD media will demand tighter tolerances for a more stable disc design. New molding technology will enable more precise substrate production. The tighter tolerances of next-generation DVD media place a premium on the accuracy of the molds and the ability to produce perfectly flat substrates to minimize jitter, tilt, and deformation to the disc that can impact read and write operations.

Along with the media improvements, the next evolution of DVD technology will likely incorporate blue-violet lasers to allow higher-density recording. The proposed blue lasers use a wavelength of 405 nanometers--compared to 650 nm for the red lasers used in current products--and a tighter 0.85 numerical aperture, allowing for a smaller spot to be recorded on the disc.

The potential for blue laser technology to play a key role in future DVD product has spurred the creation of yet another industry consortium, the Blu-Ray Disc group. The Blu-Ray proponents have issued a proposal for a next-generation DVD that has a capacity of up to 27GB per side and data rates of up to 36Mbps, three times the current standard. The Blu-Ray Disc proposal was created by a group of nine companies that include members of both the DVD Forum and the +RW Alliance. To date, the Blu-Ray proposal has not been endorsed by either group, although the DVD Forum has established a working group to consider blue-laser developments.

One issue not addressed by the Blu-Ray Disc proposal is the issue of backward read compatibility for next-generation DVD formats. While the blue laser can support vastly higher recording densities, it does not support the focus depth needed to accurately read the current generation DVD video, DVD-ROM, and DVD recordable discs. If the blue laser is adopted for use in next-generation DVD technology, it is likely that a dual-laser design--incorporating blue lasers for higher-capacity recording and red laser to read current discs-- will be implemented.

Recordable DVD is the future of optical storage. No other technology offers the capability to serve such a variety of diverse applications with a media format that provides almost universal compatibility for recorded media. The unprecedented acceptance of DVD video players, combined with the accelerating usage of recordable DVD, has created a solid a market position that should maintain DVD as the premiere optical format as the technology evolves to 100 gigabytes and beyond.

Dawn S. Wortman is senior marketing manager at Maxell (Fairlawn, N.J.)

www.maxell.com