Photonics Maintaining Competitiveness in the Information Era (1988) / Chapter Skim
Currently Skimming:
4. Opportunities in Storage and Display
4. Opportunities in Storage and Display
Pages 38-50
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 38... ...
As information-processing systems grow in complexity to handle an ever-broader range of applications as well as more sophisticated applications, the demand to store massive amounts of data and to display and print large amounts of data becomes critical. The optical technologies used in these subsystems promise the capability to store and display more information than their mechanical, electronic, and magnetic counterparts.
|
From page 39... ...
In this case, the larger storage capacity coupled with digital encoding has been utilized to improve audio fidelity. The exceptionally large storage capabilities of optical media make possible a third, unique application based on combining digital and video information on the same disk.
|
From page 40... ...
As mentioned above, optical storage has penetrated the audio application segment of this market and is starting to penetrate the printed paper segment. For the read/write applications, high storage density and data access speed comparable to those of the magnetic hard disk are key technical requirements, whereas in archival storage applications, the cost and permanence of the stored information are critical.
|
From page 41... ...
Key issues in the media today are the read and write optical power required, media lifetime, and media cost. Current methods for writing information on optical disks use the laser as a heat source for removing small spots of material (the ablative process)
|
From page 42... ...
Low manufacturing cost Potential for bit error Phase change Optical reflectivity Lower write power Lifetime change in contact Low SNR overcoat Reversible Magneto-optic Magnetic domain Reversibility Low SNR switching Most advanced technique Mcdia cxpcnsc Kerr effect readback Mcdia passivation Phase change Optical reflectivity High SNR (potential) Lin~itcd reversibility change Simpler optical system Higher write power Single-pass overwrite Dye polymer Materials flow Cost Limited reversibility Stability Lifetime Read/writc speed are critical for the writing process.
|
From page 43... ...
and European labs: Philips on laser tracking concepts and error correcting coding, INCA on high-powered lasers and archival systems, IBM on magnetooptic read/write media, and IBM/MCI and AT&T Bell Labs on ablative media. Products were developed but never introduced in the commercial marketplace (e.g., Storage Technology Corporation's gigabit file system)
|
From page 44... ...
Lasers with quantum well confinement, new alloy compositions, and nonabsorbing mirrors are being researched; the result could be lower laser threshold currents, improved efficiency, shorter wavelength, and the ability to operate a device at higher power without damage. Planar-processed laser structures might lead to better ways of coupling the optical beam from the laser or improving the beam properties.
|
From page 45... ...
Currently available systems are based on funs that can be cycled between stable and metastable phases with accompanying reflectivity or Magnetic Kerr effect changes. The quality of such funs is limiting current applications, and significant advances in the storage media would have a major impact on read/write technology.
|
From page 46... ...
Photonic displays are addressed by light beams. An example is a display where a laser beam writes on a liquid crystal cell (thermal writing process)
|
From page 47... ...
The liquid crystal display, matrix addressed, is the dominant flat panel technology (at about a 15 percent share of the total display market in 1987) , primarily in applications that cannot use CRTs.
|
From page 48... ...
panels are also present in the marketplace.9~0 Materials research directed toward improved EL efficiency, better reliability, and full color would benefit this technology. A common problem in the "gas" displays is the high cost of driver electronics.
|
From page 49... ...
The panel does not currently see any key enabling technology elements in photonic displays that would allow them to displace existing electronic display technologies or open new fields of application. Key Research Areas There should be continued research in new materials and subsystem conf~gurations, which might lead to a photonic display that is superior to its electronic counterpart in the long term.
|
From page 50... ...
1987. The picture brightens in flat panel technology.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.