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Cnt application in fed
This document discusses the use of carbon nanotubes in field emission displays. It begins with an introduction to carbon nanotubes, explaining their hexagonal structure and strong yet lightweight properties. It then discusses field emission displays and how they work using electron emission from microtips. The document proposes using carbon nanotubes as the electron emitters in field emission displays due to their high aspect ratio and ability to emit electrons at low voltages. The remainder of the document discusses the components and working principles of field emission displays, compares their attributes to other display technologies, and presents images of carbon nanotube field emission displays.
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Cnt application in fed
- 1. Carbon NanoTube Applications inFED- Device Hersh Jalil MSc. student L/O/G/O www.themegallery.com 1
- 2. Content I What is carbonnanotube (CNT)? II Application to field emission display 2
- 3. Introduction: CARBON NANOTUBES • Carbonnanotubes are hexagonally shaped arrangements of carbon atoms that have been rolled into tubes. • These tiny straw-like cylinders of pure carbon have useful electrical propeties. They have already been used to make tiny transistor and one-dimentional copper wire 3
- 4. CARBON NANOTUBES • Carbonnanotubes, composed of interlocking carbon atoms, are 1000x thinner than an average human hair – but can be 200x stronger than steel. ~10 nm
- 5. Introduction: common facts • • • • Discoveredin 1991 by Iijima Unique material properties Nearly one-dimensional structures Single- and multi-walled
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- 7. What is FED? A f i el d em s s i on di s pl ay ( FED i s a i ) di s pl ay t ec hnol ogy t hat i nc orporat es f l at panel di s pl ay t ec hnol ogy t hat us es l argearea f i el d el ec t ron em s s i on s ourc es t o i provi de el ec t rons t hat s t ri ke c ol ored phos phor t o produc e a c ol or i m age as an el ec t roni c vi s ual di s pl ay. 7
- 8. FED Principles Field emissiondisplays, electrons coming from millions of tiny microtips pass through gates and light up pixels on a screen. This principle is similar to that of cathode-ray tubes in television sets. The difference: Instead of just one "gun" spraying electrons against the inside of the screens face, there are as many as 500 million of them (microtips).
- 9. Cathode The cathode/backplate isa matrix of row and column traces. Each crossover lays the foundation for an addressable cathode emitters. Each crossover has up to 4,500 emitters, 150 nm in diameter. This emitter density assures a high quality image through manufacturing redundancy, and long-life through low operational stress.
- 10. Emission Emitters generate electrons whena small voltage is applied to both row (base layer) and column (top layer).
- 11. Pixels Faceplate picture elements (pixels)are formed by depositing and patterning a black matrix, standard red, green, and blue TV phosphors and a thin aluminum layer to reflect colored light forward to the viewer.
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- 15. Carbon Nanotube Characterised by •Superior mechanical strength (bending modulus 1 TPa) • Low weight • Good heat conductance • Ability to emit a cold electron at relatively low voltages due to high aspect ratios (102–104) and nanometer size tips (1 – 50 nm).
- 16. ATTRIBUTES HIGH RESOLUTION HIGH BRIGHTNESS LARGEVIEWING ANGLE HIGH WRITING SPEEDS LARGE COLOUR GAMUT HIGH CONTRAST LESS WEIGHT AND SIZE LOW POWER CONSUMPTION LOW COST
- 17. The development ofDisplay FED PDP LCD CRT Cathode Ray Tube Liquid Crystal Display Field Emission Display Plasma Display Panel The LCD is the major display technology, and focused in Japan, Korea and Taiwan. Then, the others nations want to catch this market, the FED is more popular in next five 17 years.
- 18. FED advantages Inherently highluminous efficiency • high contrast levels • very fast response times • Lower Power Consumption • about half that of an LCD system – Cold Cathode Emission – Distance between cathode and screen ~0.2–5mm Technology CRT (at 30KV) Luminous Efficiency (Lm/W) 3 PDP 0.8 LCD 3 OLED / PLED 5 FED at 8 KV • Capital investment for manufacturing VLS TV with printable CNT FEDs - 1/10th of LCD • Cost advantage over LCD could be 40% 7
- 19. FED Technology Roadblocks •Spindt type FED – Yield problems – Tip wear off, high vacuum – High cost of submicron technology for Spindt type emitters – High Voltage Breakdown due to electron bombardment and spacer charging – Phosphor decay in case anode is at low voltage to counter the above problem – Backscatter from anodes at high anode voltages leading to cross talk
- 20. TECHNOLOGY ATTRIBUTES Attribute Size Brightness nits Resolution InherentVA Efficiency lm/w Colour gamut Manuf. cost Cost pid Market presence PMLCD < 15” < 100 Medium Small 6 Good Medium 1 AMLCD <15” <100 High Small 6 Good V.High 5 LCOS < 1” <100 High Medium Good High 5 PDP >30” <500 High Large 1 Good Medium 1 Established Established Established Entering FED <15” <500 High Large 5 Good Medium 2 ? DLP > 60” <500 Medium Large 6 Good High 3 Established OLED No limit >10000 High Large 50 Good Low <1 In 2 years
- 21. The SEM imageof CNT-FED Zoom in 21
- 22. Carbon Nanotube FieldEmission Display (CNT-FED) FED Principle -FOWLER-NORDHEIM THEORY Mo tip 1μm Emission strongly depends on • Tip height and sharpness • Position in the well Display Technology ITRI Proc Int Disp Workshops VOL.10th;NO.;PAGE.1195-1198(2003) SEM images showing a triode type FEA with a tip radius ,400 Å J. Vac. Sci. Technol. B, Vol. 18, No. 2, MarÕApr 2000 22
- 23. Features of CNT-FED Featuresof CNT-FED ： • Ultra Thin Structure • Wide Viewing Angle • See-Through Vision • Light Self Emission • Low Power Consumption • Fast Response Time Decrease 1.Deflectiom film 2.Brightness enhancer film 3.Diffusion film 23
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Editor's Notes
- #16 APL901