Phase change optical disks overview
(With thanks to Jay and Ray, and Tom Hoff for his trail of valuable posts on optical disks over the past years,
finally I take full credit for any errors.)
From Energy Conversion Device's 10-K SEC report filed 10/3/00:
"The international standards for rewritable DVD media and systems, designed by major optical disk manufacturers, specify the use of our phase-change optical memory technology." ECD's CEO and founder, Stan Ovshinsky, has said that ECD's optical phase change work originated from his work on amorphous and phase change chalcogenides in the 1950s and 60s. From Ovshinsky's article published in "Memoires Optique et Systemes' in 1994 he says: "In July 1969 at a Gordon Conference, I described an optical memory which utilized the phase change of the Ovonic electrical
memory except that it was laser controlled." Ovshinsky's ongoing work at ECD led to the technology underlying rewritable CDs and the current multiple formats for rewritable DVD including DVD-RAM, DVD-RW, DVD+RW, plus the recently announced UDO (ultra density optical) and ML (multilevel phase change recording).
CD stores 650 megabytes, DVD stores 4.7 gigabytes/side and UDO phase change optical from Sony will be introduced with 40 gigabytes per disk and Sony aims to double and triple that. ML will increase the existing CD RW disks capacity and transfer rate three fold to 2 gigabytes and increase write speed to 36X on a fresh disk. ML developers state that ML can and will be applied to DVD rewritables in the future. Technology is increasing the storage capacity and transfer rate of phase change media-based optical disks so that these disks can in the future offer recording speed and capacity sufficient for several hours of full resolution HDTV (1080i) recording for the consumer and large, fast data retrieval for commerce.
Phase change disks are coated with a special mixture of elements, chalcogenides, which can exist in an amorphous (disordered phase) or in a crystalline (ordered) phase. This mixture can be heated by a laser focussed on a spot on the disk to change that targetted spot of the mixture into the amorphous phase or, with lower heat, back into the crystalline phase. This reversal can occur thousands, in some formulations hundreds of thousands of times. It is this reversability that allows for rewritability. CD-R, a write-once-read-many disk media, undergoes a one time, irreversible, phase change of its recording substance, usually an organic dye, during recording while CD-ROMs are recorded by physically pitting the disks to alter reflectivity in a bulk recording/replicating process. Reading these disk media all depend on a difference in reflectivity of the written 'pit' versus the unwritten intervening space on the disk.
Data recorded on rewritable phase change optical disks is non-volatile and remains stable on the disk for 100 years or more. Prices for CD-RW quoted from disk-o-tape.com today are $1.58/disk for Sony 10-packs with CD-R quoted at $.74/disk for a Sony 10-pack. With current manufacturing costs and market pricing, CD- RW is priced slightly more than double CD-R and the price is dropping for both.
RW disks are made by sputtering the rewritable chalcogenide layer in its' amorphous phase on a polycarbonate disk substrate. Then a protective lacquer coating is applied and the disk is then subjected to heat to change the chalcogenide to its' crystalline phase for delivery to the user ready for recording/rewriting. This added heating step, called 'initialization', adds time to the manufacturing process compared to the CD-R organic dye disks, but newer chalcogenide formulations have been developed that require less initialization time and energy and should reduce cost further.
Writing to the disk involves quickly heating the crystalline phase to its' melting point and then quickly cooling it, called quenching, into its' amorphous phase. The amorphous phase is the written 'pit', it is stable and has low reflectivity. Erasing the disk is done by moderately heating the amorphous phase, called annealing, which then returns the chalcogenide recording layer to the crystalline phase which has high reflectivity. In practice, one recording laser does both in a direct overwrite pattern, oscillating between the higher temperature for melting to write and the lower temperature for erasure. A second and lower energy laser reads the recording by measuring the low reflectivity of the amorphous 'pits' and the high reflectivity of the crystalline 'lands' and registers them as 0s and 1s in a binary fashion. (Actually, the reading laser reads the edge transition from pits to land.) Current 4.7 GB (gigabyte) rewritable DVDs can be recorded to at 11 Mbps (11 million bits per second). Phase change in development, (see ML below) will give 30 Mbps, enough for HDTV recording. 100 Mbps is in advanced lab testing. In terms of minimum write pulse, current commercial units are 50-100 ns (nanoseconds), but the technology is readily capable of <10 ns at higher cost, and there are lab demos running even faster.
These advances illustrate the capacity for growth of ECD's phase change technology both in data density and data transfer speeds. Sony staunchly advanced magneto-optical (MO) 5.25" storage for the past decade, continually doubling capacity, but on November 1st, 2000 announced that a 40 GB UDO phase change 5.25" disk would be positioned as the successor to their MO disks, after the next MO upgrade to 9.1 GB. UDO will supercede MO using phase change media combined with violet lasers and improved near field optics and Sony will also work on development of 80 GB and 120 GB capacity disks. The next day, HP and Plasmon, the two main manufacturers for MO storage, stated they would adopt Sony's new UDO standard.
On October 31st, 2000 Calimetrics announced an alliance to launch ML (multilevel) disks which would initially allow CD-RW phase change disks to triple storage and transfer rates without violet lasers and without enhanced near field optics. CD-RW write speeds would increase from 12X to 36X with current optical disk drives just by adding an integrated circuit or two to read the multi-levels and "fine tuning" of the phase change disk media. Calimetrics and Energy Conversion Devices worked jointly on the ML project beginning in November 1997 aided by a $10 million grant from the Advanced Technology Program (ATP), a division of the National Institute of Standards & Technology (NIST) to increase DVD recordable capacity 10-fold and data transfer rates up to 5-fold.
ML is the fruitful outcome of this grant-supported collaboration. ML has at least 8 levels of reflectivity at each point/locus/cell on a phase change disk allowing for 3 bits/cell in binary terms. (Per their paper presented to the Optical Data Society in May 2000, Calimetrics' ML only uses 5/6 of the 3 bits available, or 2.5 bits/data cell for data encoding versus standard 1.4 bits/data cell (1.8 X multiplier) and combines this with decreases in cell size (1.4X multiplier) and increases in efficiency (1.2X multiplier) to net out to a three-fold gain in disk capacity and speed.) Instead of a 'black and white' recording of amorphous pits and crystalline lands, there is a 'gray scale' with 8 distinct levels of reflectivity created by continuous shifts in the relative proportions of the two phases. (This is analogous to the multilevel phase change in OUM, Ovonic Unified Memory, with varying proportions of electrically conductive crystalline chalcogenide and resistive amorphous chalcogenide for electronic computer memory. In the future, OUM could wind up in the chip circuitry of optical disk drivers... see the ECD/Ovonyx recent licensing with STMicroelectronics and STM's plans for chips in disk recorders.)
ML can be enhanced further by reducing the cell size using near field optics (technology acquired from the third ATP partner, Polaroid, by Calimetrics) to yield an overall 8-fold capacity increase for CD-RW to 5 GB, and a 5-fold increase for rewritable DVDs. Calimetrics states that adding blue lasers to all of the above provides "a clear path to 25 GBs/layer." Calimetrics' website currently has a cartoon pictorial showing progressive steps via ML to 250 GB DVD disks in 2006! ML technology clearly advances the performance of ECD's underlying optical phase change technology today and into the future.
ECD was the sole recipient of a second grant from the ATP in October 1997 "to apply its' expertise in roll-to-roll vacuum deposition manufacturing and phase change materials to develop a process technology that both formats and coats DVD disks as part of a continuous low cost manufacturing system. The major technical challenges are to emboss the substrate continuously and coat thin films in a series of high-rate vacuum deposition chambers, ending in deposition of a protective film. If successful this process will increase throughput ten-fold and reduce the unit manufacturing costs by a factor of two to four." This $2 million govt. grant out of a total budget of $5.9 million was scheduled for completion in Oct '99.
Five months later, in March 2000, GE formed a JV with ECD, GE Ovonic Media ( 51% GE, 49% ECD) to "design, develop, demonstrate and commercialize continuous web roll to roll technology for ultra high speed manufacture of optical media - primarily rewritable DVDs." GE Plastics manufactures Lexan, its' trademarked polycarbonate, which is used as a substrate in optical disks. (Sidenote: Bekaert steel would invest in ECD roll-to- roll solar thin film deposition onto a steel substrate the following month.) This JV is structured so that GE is funding the project and ECD is providing its' intellectual property, so costs are primarily borne by GE. ECD Chmn. Bob Stempel said in the 5/16/00 conference call, that it was the successful conclusion of ATP/NIST for development of a new, fast low cost manufacturing system for DVDs that led to this new agreement with GE Plastics. The new manufacturing process exceeded the goals of the ATP study with this new manufacturing process expected to have 10X lower costs and 30X the throughput of existing rewritable disk manufacturing processes.
In the Nov 2000 Conference Call, Bob Stempel gave the following update on GE Ovonic:
"Two of our key milestones were successfully met in October:
embossing, the principle has been demonstrated with good progress
towards actual disks. Deposition, the write and erase capability was good
and approaching the final specification." and that GE had
congratulated the ECD team on these accomplishments.
In late January 2001 in the WSCR.com, Stan Ovshinsky was quoted as saying: "With GE, we are going into manufacturing." And in the quarterly conference call of February 16th, 2001Stan spoke of ECD's broad emphasis beyond licensing and royalties towards direct manufacturing of ECD's products in joint ventures with world-class partners. Stan pointed out that ECD invents and designs the materials into useful product, then designs the proprietary manufacturing process and finally builds the actual manufacturing machinery.
While ECD and GE refine ultra high speed optical disk manufacturing capability, a format war between competing rewritable DVD disk formats rages on. The DVD Forum, an industry standards group, in 1997 adopted two formats DVD-RAM and
DVD-RW. Shortly thereafter, Sony and Philips, despite being members of the DVD Forum, backed a third competing format, DVD+RW, which is still not endorsed by the DVD Forum. These competing formats are all incompatible with one another and have varying degrees of backward compatibility with standard DVD players out on the market. DVD-RAM has the least compatibility with DVD players and can only be played on DVD players specifically modified to accept DVD-RAM disks. DVD-RW disks were designed to generally be playable on many newer DVD players. DVD+RW was designed to be playable on most DVD players. All formats are available now in 4.7GB disk capacity, approximating that of a standard format DVD movie for rent or purchase.
DVD-RAM was launched first in 1998, backed by Hitachi and Panasonic,, as a PC peripheral storage device, with 200,000 units shipped that year. DVD-RAM has the most flexible PC storage use of these formats and allows for easy 'drag and drop' of files on a PC or Mac and drives are available now well under $300. The DVD-RAM disk media is durable and can be rewritten to up to 100,000X.
DVD-RAM videorecorder units from Hitachi are just now being introduced in Japan priced at $4000. DVD-RAM uses rewritable media only and has no write once (-R) media that is available with DVD-RW. DVD-RAM is an option on the Apple PowerMac G4, some IBM , Dell computers and most recently Compaq computers. In 2000, with the only other competition being DVD-RW video recorders from Panasonic available in Japan at $2500 each and selling 6000 units/mo in the first four months after their November 1999 launch, DVD-RAM drives captured over 90% of the year 2000 DVD rewritable worldwide unit sales. In year 2000 this amounted to ~600,000 units. However, Panasonic had projected that 9 million DVD-RAM units would be shipped in 2000 and as recently as February 2001 their website still featured those overly optimistic projections.
What accounts for this disparity? Buyers didn't buy recordable DVD as expected despite DVD-RAM's 'here today technology'. Instead, CD-RW drive sales which were forecast to peak in 2000 with a shift towards DVD rewritables, continued to grow from 12.5 Million in 1999, to 30 Million in 2000 and were recently projected at 40-50 Million units in 2001. The public and the resellers are buying CD-RW's compatibility with existing CD players and foregoing higher storage/transfer rate of these competing DVD rewritable formats that are only variably backwards compatible DVD players at best for now. The recent ML multilevel technology is targetting this widely accepted rewritable CD market to launch its' tripling technology on first with 2GB CD rewritable disks while awaiting a victor in the DVD rewritable format war.
Meanwhile, DVD-RW the second DVD Forum approved format, backed by Pioneer and 27 other companies, has had a much slower launch (as mentioned above with the DVD-RW video recorder launch in November 1999 in Japan.) This format was designed for home video recording and the Forum settled on 1000X rewrite cycles as sufficient. In May 2000 in response to leading DVD-RAM sales, the DVD-RW backers decided to promote DVD-RW as a PC peripheral as well and to study improving its' future cross-compatibility with DVD+RW (note Sony, Ricoh are backers of both -RW & +RW formats.) DVD-RW has the ability to record to DVD-R, analogous to the widely popular CD-R, and Apple and Compaq announced in January 2001 that they would be adding DVD-R computer drive units. Pioneer announced in February 2001 that they would be offering a DVD-RW PC drive that would write on DVD-RW, DVD-R, CD-RW and CD-R priced at $995 and available by late February. These combination rewritable drives enhance DVD-RW's competitive stance because of the multiple media media that can be used for recording and the DVD-RW disks are playable in many of the standard DVD players.
DVD+RW was the third format, announced by Sony and backed by Philips,
Hewlett-Packard, Ricoh and others, and though not a specified format of the Forum, it was designed to be the most backward compatible with existing DVD players. Units were delayed until Nov 2000 when they were finally demonstrated at Comdex. Like all the competing DVD formats, 4.7 GB of disk storage is offered. DVD+RW can be rewritten up to 100,000X. DVD+RW like DVD-RW is designed for videorecording. DVD+RW does not require 'finalization,' a step that DVD-RW disks do require to make the contents of the disk readable on DVD players and that must be repeated each time additional recording is done on a DVD-RW disk. HP expects to have a DVD+RW PC drive by mid-2001 priced under $1000 and this driver is likely to be multi-function for CD-R and CD-RW as well. Philips DVDR 1000 recorder should be out mid-2001 priced between $2000-$3000.
Sony expects to release a rewritable DVD by mid-2002 and promises that this model will read and write in both DVD+RW and DVD-RW. This will be almost five years after Sony originally announced the DVD+RW format prompting one industry observer to quip: "It's like waiting for Godot." But such cross compatibility if available today would likely be a powerful incentive to buyers and resellers.
In sum, these three formats are incompatible with one another, though some -RW and +RW OEM backers may link these two in future designs. These three formats backward compatibility with existing DVD players ranges from nil with DVD-RAM (save for its' backers own new DVD players) to fair with DVD-RW and good with DVD+RW but their availability on the current market is the inverse of this compatibility! To reduce some roadblocks, the DVD Forum proposed the 'DVD-Multi' specification last July. Only DVD players capable of reading DVD-ROM, -RAM, -RW and -R disks could be designated as "DVD Multi' players and similarly only DVD recorders capable of writing to -RAM, -RW and -R disks could be designated as 'DVD Multi' recorders. All this is doable but at added cost and the manufacturering members of the Forum must decide individually if they will build such drives.
Behind all this competitive chaos looms further improvements which might render the victor of the first DVD war obsolete... blue lasers and higher aperture near field optics yielding smaller spot sizes and 50 GB disks with even faster data transfer rates. Toshiba and Hitachi are forecasting such disks and drivers by 2005, probably just in time for digital recording of high definition television. While the overall CD/DVD recordable market is expected to have 45% growth compounded annually through 2004, competing HDTV broadcast standards are still being debated in Congress. Another unresolved issue is digital copy protection standards... they aren't set yet and a full high definition DVD copy is almost as good as what is projected at the local cinema, so the Entertainment Industry wants a copy protection that prevents making full definition copies or ensures payment for and limited use of such copies. Hollywood and the DVD recording industry will need to find a common ground.
If you have a satellite or cable connection, most inputs are analog, so full digital
copies are not possible and giving full HDTV bandwidth on cable would reduce the cable operator's number of channels and revenue. However, PCs with IEEE 1394 "Firewire"
do have high bandwidth digital input and with HDTV tuner cards fed from good old rooftop antennas, well.... full digital copies on disk will be possible.
Will DVD-R be the trojan horse for DVD-RW to ultimately win the battle? Will Sony's dual backing of -RW and +RW with promised compatibility come too late? Will DVD-RAM be able to succeed in entering the home recording market and grow its' current lead in PC peripheral storage?
My take on this is that DVD-RAM is a great buy for PC storage now (so is ML's upcoming triple CD-RW) and that DVD video recorders are now or are soon to be available in all 3 formats for $2000, likely to fall to $1000 next year and $500 in 2003.
In 2003/4, with DVD players already the greatest selling consumer electronics device ever, I expect $400-$500 DVD rewritables to surpass VCRs and never look back. And whichever format wins, ECD's phase change optical disks will be inside.
Al
Nagging loose ends:
1. Royalty rate just isn't clear but thanks to Tom Hoff, here is the best post I can find #3560 from this board:
To:fred whitridge who wrote (3559)
From: Tom Hoff
Friday, Apr 16, 1999 9:28 AM
View Replies (1) | Respond to of 5925
Fred, the 1.5% up to a million dollars and 1% there after has been confirmed in two
conference calls by Nancy Bacon.
2. Which major rewritable disk manufacturers are not licensed and where are we in negotiations? Mitsubishi is not last I checked and they are cited as THE tech partner to provide the disk media for ML.
3. Tom Hoff, as I revisited today, cited Stempel at the time of the GE Ovonic merger as
predicting we would have disk product in two years. I didn't hear this call but if Tom
is correct, then a buildout of disk producing plant should be imminent.
3. Did we broadly license optical disks to ITRI such that they could sublicense this tech
as I think retiarius raises this possible scenario?
4. Where is ECD today with the 'Optical Royalty Trust' that was formed as an outgrowth of the Manning and Napier settlement back around 1990(?) was to set aside 25% of the optical royalties in this trust? Is there a cap? How much remains to be deposited and for how long? Would it even apply to profits from our own manufacturing of disks?
5. Can our high speed roll to roll produce the 'fine tuned' phase change media used in
upcoming multilevel rewritable disks? |
