- Surface-conduction electron-emitter display
A surface-conduction electron-emitter display (SED) is a
flat panel displaytechnology that uses surface conduction electronemitters for every individual display pixel. The surface conduction emitter emits electrons that excite a phosphorcoating on the display panel, the same basic concept found in traditional cathode ray tube(CRT) televisions. This means that SEDs use tiny cathode ray tubes behind every single pixel (instead of one tube for the whole display) and can combine the slim form factor of LCDs and plasma displays with the superior viewing angles, contrast, black levels, color definition and pixel response time of CRTs. Canon also claims that SEDs consume less power than LCD displays.
The surface conduction electron emitter apparatus consists of a thin slit across which electrons tunnel when excited by moderate
voltages(tens of volts). When the electrons cross electric poles across the thin slit, some are scattered at the receiving pole and are accelerated toward the display surface by a large voltage gradient (tens of thousands of volts) between the display panel and the surface conduction electron emitter apparatus. Canon Inc.working with Toshibauses inkjet printing technology to spray phosphors onto the glass. The technology has been in development since 1986.
A related technology also currently in development is
Field Emission Display(FED) which uses multiple redundant emitters per area of display rather than a single emitter. SED is generally considered the more commercially viable of the two.
Canon began SED research in 1986 and, in 2004,
Toshibaand Canon announced a joint development agreement originally targeting commercial production of SEDs by the end of 2005. The 2005 target was not met, and several new targets since then have also slipped by. This failure to meet mass-production deadlines goes as far back as 1999, when Canon first told investors of its intentions to immediately begin mass-producing the technology. The lack of tangible progress has worried many investors and has prompted many critics. One critic called SED “the best display technology you’ve ever seen that may be stillborn.”cite web|url=http://gear.ign.com/articles/679/679235p1.html|title=CES 2006: Toshiba's Plasma/LCD Killer|publisher=ign.com|date=|accessdate=] Toshiba and Canon again delayed their plan to sell the television sets to the fourth quarter of 2007.cite web|url=http://www.twit.tv/24|title=this WEEK in TECH Episode 84: Hahn, I'm Home!|publisher=Leo Laporte|date=January 15, 2007]
In October 2006, Toshiba's president announced the company plans to begin full production of 55-inch SED TVs in July 2007 at its recently built SED volume-production facility in Himeji.cite web|url=http://online.wsj.com/article/SB116672776608256958.html|title= Toshiba, Canon work on displays|publisher=Dow Jones & Company, Inc.|date=
2006-12-22|accessdate=2006-12-22] but they do not expect SED displays to become a commodity and will not release the technology to the consumer market because of its expected high price, reserving it solely for professional broadcasting applications. [http://techon.nikkeibp.co.jp/english/NEWS_EN/20061225/125850/ SED Won't Become Commodity -- Toshiba's President Nishida Said at Year-End Press Gathering] December 25, 2006 Masao Oonishi, Nikkei Microdevices]
Also in December 2006, it was revealed that the delays in SED TV mass production were caused by litigation between
Applied Nanotech, a subsidiary of Nano-Proprietary, and Canon. Nano-Proprietary claims that Canon broke an exclusivity agreement by sharing information related to electron emissions from carbon nanotubeswith Toshiba. The litigation has been reportedly ongoing since April 2006.
January 12, 2007, Toshiba announcedcite web|url=http://gear.ign.com/articles/755/755742p1.html|title=Canon Buys Toshiba Out of SED|publisher=IGN|date= 2007-01-16|accessdate=2007-01-18] The company must purchase 50% of Toshiba shares to produce SED TVs on its own.cite web|url=http://www.yepeoo.com/canon-p.html|title=Canon wants its own TVs|publisher=Yepeoo.com|date=|accessdate=] Canon was still planning a release of SED displays in Japan during the 4th quarter of 2007, while 'reassessing' its future mass-production plans for SED panels.
February 22, 2007, Federal Judge Samuel Sparks, with the U.S. District Court for the Western District of Texas, ruled in a summary judgment that Canon violated its agreement with Texas-based Nano-Proprietary by forming a joint television venture with Toshiba.cite web|url=http://news.com.com/2100-1047_3-6161591.html?part=rss&tag=2547-1_3-0-5&subj=news|title=Judge rules against Canon in nanotube TV case|publisher=CNET|date= 2007-02-22|accessdate=2007-02-23] However, on May 3, 2007, a jury ruled that no additional damages beyond the $5.5m fee for the original licensing contract were due.cite web|url=http://www.marketwire.com/mw/release_html_b1?release_id=247962|title=Nano-Proprietary, Inc. Announces Verdict in Canon Litigation|date= 2007-05-03|accessdate=2007-05-06] cite web|url=http://www.canon.com/press/2007/sed2007may4.html|title=Notice Regarding Litigation with Nano-Proprietary Involving SED|date= 2007-05-07|accessdate=2007-05-07]
May 25, 2007, Canon again announced due to prolonged litigation, it will postpone the launch of SED televisions, originally planned for October-December 2007. The company said it will announce a new launch date in the future.cite web|url=http://www.ca5.uscourts.gov/opinions/pub/07/07-50640-CV0.wpd.pdf|title=Appeal's Court Ruling] .
contrast ratio. According to IGN at the 2006 CES show, Canon's final versions of SEDs will ship with a contrast ratio of 100,000:1.
Brightnessof 450 cd/m2.screen burn-in. This was a constant problem for people using CRT television monitors for security camera systems. Early plasmas also had this problem, but with phosphor development, the problem has largely been reduced.Fact|date=August 2008
Comparison of display technology
* [http://www.oled-display.info SED-TV News and Information]
* [http://www.canon.com/technology/canon_tech/explanation/sed.html Canon Technology SED showcase]
* [http://techon.nikkeibp.co.jp/english/NEWS_EN/20050421/104026/ SED News - April 2005]
* [http://www.toshiba.co.jp/about/press/2006_03/pr0801.htm Toshiba Press Release]
* [http://www.sed-tv-reviews.com SED TV Reviews]
* [http://gear.ign.com/articles/679/679235p1.html IGN: CES 2006 preview - Jan 2006]
* [http://www.soundandvisionmag.com/article.asp?section_id=7&article_id=1203 Sound and Vision - Jan 2006]
* [http://www.behardware.com/articles/593-1/close-encounters-of-the-third-kind-sed.html Close Encounters of the Third Kind: SED - Jan 2006]
* [http://www.hdtvexpert.com/pages_b/sedtech.html Standing in the shadows - March 2006]
* [http://www.nature.com/nmat/journal/v4/n12/full/nmat1516.html Identifying and counting point defects in carbon nanotubes ...] - Nature Photonics
* [http://www.nature.com/nphoton/journal/v1/n5/full/nphoton.2007.65.html Funding for organic-LED technology, patent disputes, and more ...] - Nature Materials
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Surface-conduction electron-emitter display — Pour les articles homonymes, voir Surface (homoymie). Surface conduction Electron emitter Display (SED) désigne une technologie d affichage destinée aux écrans plats, développée conjointement par … Wikipédia en Français
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