Disks, tape vie for DTV storage duties
By Yoshiko Hara, EE Times
Oct 6, 2000 (12:18 PM)
URL: eetimes.com
MAKUHARI, Japan — The technology war between optical disks and digital tape escalated this past week at the mammoth,
multi-industry Ceatec Japan 2000 trade show, with volleys launched from developers on both sides of the breach. Sony and Pioneer
showed prototypes of a capacious optical-disk storage system, DVR-Blue, aimed at recording digital satellite television broadcasts.
Using a violet laser from Nichia Chemical Industries and a thin, 0.1-mm recording layer, DVR-Blue can store 22.5 Gbytes on one side
of a 12-cm-diameter optical disk.
On the digital VHS front, Victor Company of Japan Ltd. (JVC) announced a D-VHS videotape recorder with a high-speed mode
capable of storing up to four hours of high-definition TV programming. The longest available tape can store 50 Gbytes of data in
high-speed mode at 28.2 Mbits per second.
Matsushita, Hitachi and Toshiba also showed prototype D-VHS digital tape recorders at the show. And hard-disk drives configured
for video recording and, in some cases, offered in tandem with recordable DVD drives or tape were shown at Ceatec by Sony,
Toshiba and others.
Japan, for the most part, lacks the cable TV infrastructure that exists in the United States and elsewhere, which biases the
consumer electronics industry here toward satellite broadcasting of not only digital movies and television but also data.
$1 billion question
That begs the billion-dollar question: What systems can record those digital high-definition programs?
The prototype DVR-Blue systems extend the format conflicts of the 1990s between the Sony- and Toshiba-led camps. The DVD
group, which includes most of Japan's largest companies, has a road map that calls for high-density recordable systems with 15
Gbytes or more of capacity. But most of the companies in the DVD camp are supporting D-VHS videotape recorders as the most
practical near-term means of recording high-definition programs digitally.
Meanwhile, the DVR-Blue prototypes developed by Sony and Pioneer have no compatibility with the mainstream DVD format, which
stores about 4.7 Gbytes per disk.
Pioneer and Sony initially had separate development programs for high-density disks but decided about a year ago to combine
resources. Sony has been pursuing a high-density disk technology with a shallow recording layer. Standard DVD-format disks are
made by bonding two 0.6-mm-thick disks, putting the recording layer 0.6 mm below the surface. For the DVR-Blue disk, the
recording layer is only 0.1 mm from the surface. That permits higher densities but requires more precise manufacturing techniques,
with smaller operational margins for error.
"Sony believes that the mainstream will move toward high-capacity, shallow disks," said a Sony spokesman.
For its part, Pioneer has been pursuing the use of blue lasers for high-density optical-disk systems, including prototypes based on a
Pioneer-developed second-harmonic-generation (SHG) laser. A prototype system based on Nichia's violet laser and achieving a
27.4-Gbyte capacity was shown at last year's Japan Electronics Show.
For DVR-Blue, Sony provided the laser pickup, including the lens subsystem, while Pioneer provided the electron-beam mastering
technology, which enables the fine-pitch cutting of the disks.
The DVR-Blue recorder uses a phase-change disk and a high-power violet laser from Nichia that began sampling only last month. The
laser emits 405-nanometer light, with 30 mW of power in continuous-drive mode. To focus the 405-nm laser on the recording layer
just beyond the 0.1-mm cover, Sony developed a set of two lenses that condense the laser spot in two steps. The recorder thus
can read and record in 0.3-micron-pitch tracks, at a density of 0.13 micron2 per bit, which is less than half of the current DVD
disks. The distance between the disk surface and the lens is just 150 microns.
"The disks have to be housed in a cartridge for dust protection and precise control," the Sony spokesman noted.
The 22.5-Gbyte capacity translates into 2 hours of recorded high-density programming, at a transfer rate of 24 Mbits/s, the rate
used for satellite TV broadcasting. Pioneer's recorder can go faster, up to 35 Mbits/s, a Pioneer spokesman said. The two companies
said that the prototypes are capable of recording, but they demonstrated only playback at the show.
JVC said its HD D-VHS system is the first to be able to record high-definition programs at their original definition. The VCR is also the
first video recorder to support the IEEE 1394 interface.
JVC formed the Digital Hi-Vision Video Initiative together with Hitachi Ltd., Matsushita Electric Industrial Co. Ltd., Mitsubishi Electric
Corp. and Toshiba Video Products Japan to promote high-speed mode D-VHS. Fuji Photo Film, Hitachi Maxell, LG Electronics, Philips,
Samsung, Sanyo, Sharp, Sony, TDK and Thomson Multimedia have endorsed the logo mark and the exchange of technical information
concerning the recorder format.
Hard-drive-based recorders also were prominent at Ceatec. Sony showed a 30-Gbyte hard drive that will debut in Japan in August
for home video recording. Toshiba showed a combo prototype that marries a DVD-RAM drive with a hard drive.
JVC is set to launch a combination VHS tape recorder and 20-Gbyte hard drive in November. And Sharp showcased a prototype that
puts a broadcast satellite tuner and a 30-Gbyte hard drive in a set-top box, enabling direct digital input.
Matsushita, Sony and Toshiba are working on draft specification for the use of hard drives in digital TV program recording. And the
Association of Radio Industries and Businesses (ARIB), an industry organization consisting of major manufacturers, broadcasters and
other concerns, is expected to create standards for HDD-based recorders for home use by next summer.
Nichia set to sample 400-nm laser diode
By Yoshiko Hara, EE Times
Jan 12, 1999 (12:15 PM)
URL: eetimes.com
ANAN, Japan — A short wavelength laser that could essentially double or triple the capacity of an optical disk will be available for
sampling from Nichia Chemical Industries Ltd. in February. Nichia, which expects to become the first volume supplier of InGaN-based
blue-violet laser diodes, next month will sample a 400-nanometer violet semiconductor laser with a lifetime of about 10,000 hours
and a constant output power of 5 milliwatts. Production is expected to begin soon after sampling commences.
Nichia has already presented papers on laser diodes with lifetimes of 10,000 hours when operating at 2 mW output power. For
commercialization, Nichia has improved the structure between the sapphire substrate and the laser diode structure.
The DVD Forum said a short wavelength laser in the blue or shorter range is the key component for a third-generation DVD-RAM disk
with a capacity above 15 Gbytes.
++++
Looks like the Nichia guys have got themselves a design win with the new recording technology. Sapphire based violet lasers, I believe, are not as cost effective as the SiC based CREE blue lasers. No pricing info on the Nichia, but this would seem to indicate that the life-cycle problems have been addressed.
Jim |
