06_Part_03_Dipsplay And Photosensing Systems

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DISPLAY SYSTEMS AND PHOTOSENSORS
(PART 3)
LCD
TFT
LED-OLED
CCD
CMOS
Introduction to:
OLED
and
PLED
Mehdi.SHarif
 Organic light-emitting diodes (OLEDs) have made great progress since the first
presentation of thin film devices based on small molecule organic materials by
Tang and VanSlyke in 1987.
 The OLED performance and stability have been rapidly increased over the last
years.

Also, the size of the devices is growing and several applications like displays
and general lighting are produced.

The developments for lighting applications will reach high efficiencies and low
cost production to replace fluorescent and phosphorescent lamps.
 Because of very thin active layers (several 10–100 nm), the low material
amount used for the production of OLED results in cheap and lightweight
products
• An organic light emitting diode (OLED) is a light
emitting diode
• In OLED the emissive electroluminescent layer is a film
of organic compounds .
• There are two main families of OLEDs: those based upon
small molecules and those employing polymers.
• Adding mobile ions to an OLED creates a Light-emitting
Electrochemical Cell or LEC, which has a slightly
different mode of operation.
• An OLED display functions without a backlight. Thus, it
can display deep black levels and can be thinner and
lighter than liquid crystal display (LCD).
•
Bottom or top emission:
•
Transparent OLEDs: it much easier to view displays in bright
sunlight
•
Inverted OLED:
 STACKED OLEDS :
Molecules commonly used in OLEDs include organometallic chelates
chelate
Alq3
Tris(8-hydroxyquinolinato)aluminium
Perylene
Alq3 has been used as a green emitter, electron transport material and as a host for
yellow and red emitting dyes.
 Polymer light-emitting diodes (PLED), also light-emitting
polymers (LEP), involve an electroluminescent conductive
polymer that emits light when connected to an external
voltage.
derivatives of poly(p-phenylene vinylene) and polyfluorene
poly(p-phenylene vinylene)
The first blue light emitting polymer diode was produced with a substituted
polyfluorene
polyfluorene
 vapor thermal evaporation (VTE)
 Color patterning
• Vacuum deposition is not a suitable method for forming
thin films of polymers.
• Polymers can be processed in solution, and spin coating is
a common method of depositing thin polymer films.
• The metal cathode may still need to be deposited by
thermal evaporation in vacuum.
 Lower cost in the future:
 Light weight & flexible plastic
substrates:
 Wider viewing angles & improved
brightness:

Better power efficiency:
LCDs filter the light emitted
 Response time
Disadvantages
Lifespan: The biggest technical problem for OLEDs was the limited
lifetime of the organic materials
a lifetime of around 14,000
Color balance issues
Water damage
UV sensitivity
MANUFACTURERS AND
COMMERCIAL USES
•
Samsung applications
•
Sony applications
•
LG applications
15 inch 15EL9500
REFERENCES:
• http://en.wikipedia.org/wiki/Organic_light-emitting_diode
• http://en.wikipedia.org/wiki/Chelation
• http://electronics.howstuffworks.com/oled1.htm
• http://www.jbibbs.com/hdtutorial/futuretech.htm
• http://www.oled-display.net
• Sung-Jin Kim ,Yadong Zhang,Organic Electronics 12 (2011)
492–496
• M. Eritt , C. May a, K. Leo et al Thin Solid Films 518 (2010)
3042–3045
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