Disks, tape via for DTV storage duties
By Yoshiko Hara
EE Times
(10/06/00, 3:18 p.m. EST)
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.
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