Organic light emitting diode OLED seminar or presentation report
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01-01-2010, 12:19 PM



.doc   light emiting polymers seminar report.doc (Size: 693 KB / Downloads: 1,319)
ABSTRACT
Organic light emitting diode (OLED) display technology has been grabbing headlines in recent years. Now one form of OLED displays, LIGHT EMITTING POLYMER (LEP) technology is rapidly emerging as a serious candidate for next generation flat panel displays. LEP technology promises thin, light weight emissive displays with low drive voltage, low power consumption, high contrast, wide viewing angle, and fast switching times.
One of the main attractions of this technology is the compatibility of this technology with plastic-substrates and with a number of printer based fabrication techniques, which offer the possibility of roll-to-roll processing for cost-effective manufacturing.
LEPs are inexpensive and consume much less power than any other flat panel display. Their thin form and flexibility allows devices to be made in any shape. One interesting application of these displays is electronic paper that can be rolled up like newspaper.
Cambridge Display Technology, the UK, is betting that its light weight, ultra thin light emitting polymer displays have the right stuff to finally replace the bulky, space consuming and power-hungry cathode ray tubes (CRTs) used in television screens and computer monitors and become the ubiquitous display medium of the 21st century.

INTRODUCTION
Light emitting polymers or polymer based light emitting diodes discovered by Friend et al in 1990 has been found superior than other displays like, liquid crystal displays (LCDs) vacuum fluorescence displays and electro luminescence displays. Though not commercialised yet, these have proved to be a mile stone in the filed of flat panel displays. Research in LEP is underway in Cambridge Display Technology Ltd (CDT), the UK.
In the last decade, several other display contenders such as plasma and field emission displays were hailed as the solution to the pervasive display. Like LCD they suited certain niche applications, but failed to meet broad demands of the computer industry.

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28-01-2010, 01:30 PM


.doc   LIGHT EMITTING POLYMER seminar.doc (Size: 850.5 KB / Downloads: 479)
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21-02-2010, 12:31 PM


.doc   OLED.doc (Size: 679.5 KB / Downloads: 694)
ORGANIC LIGHT EMITTING DIODE (OLED)


OLED is a solid state device composed of thin films of organic molecules that create light with the application of electricity.OLEDs can provide brighter.crisper displays on electronic devices and use less power than conventional light emitting diodes(LEDs)used today.
Like an LED,an OLED is a solid state semiconductor device that is 100 to 500 nanometres thick or about 200 times smaller than a human hair.OLEDs can have either two layers or three layers of organic material. An OLED consist of the following parts:
• Subtrate
• Anode
• Organic layers
• Cathode
OLEDS emit light through a process called electrophosphorescene. Different types of OLEDs are
• Passive-matrix OLED
• Active-matrix OLED
• Transparent OLED
• Foldable OLED
• Top-emitting OLED
• White OLED Applications
Currently.OLEDs are used in small-sreen devices such as cell phones,PDAs and digital cameras.Research and development in the field of OLEDs is proceeding rapidly now and may lead to future applications in heads-up displays,automotive dash boards etc.
INTRODUCTION
Can we just imagine of having a TV which can be rolled up? Would'nt you like to be able to read off the screen of your laptop in direct sunlight? Your mobile phone battery to last much, much longer? Or your next flat screen TVto be less expensive, much flatter, and even flexible? Well, now it is possible by an emerging technology based on the revolutionary discovery that, light emitting, fast switching diode could be made from polymers as well as semiconductors.

We know, ordinary LED emits light when electic current is passed through. Organic displays use a material with self luminous property that eliminates the need of a

back light. These result in a thin and compact display. While backlighting is a crucial component to improving brightness in LCDs, it also adds significant cost as well as requires extra power. With an organic display, your laptop might be less heavy to carry around, or your battery lasts much longer compared to a laptop equipped with a traditional LCD screen.

A screen based on PolyLEDs has obvious advantages: the screen is lightweight and flexible, so that it can be rolled up. With plastic chips you can ensure that the electronics driving the screen are integrated in the screen itself. One big advantage of plastic electronics is that there is virtually no restriction on size.

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23-08-2010, 02:03 PM

can anyone send me a ppt on Organic LEDs??
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27-09-2010, 11:50 AM


.ppt   Organic Light Emitting Diodes.ppt (Size: 490.5 KB / Downloads: 580)


Organic Light Emitting Diodes(OLEDs)

presented by::-
Physics 496/487
Matt Strassler




abstract:-


Lighting efficiency
Incandescent bulbs are inefficient
Fluorescent bulbs give off ugly light
LEDs (ordinary light emitting diodes) are bright points; not versatile
OLEDs may be better on all counts

Displays: Significant advantages over liquid crystals
Faster
Brighter
Lower power

Cost and design
LEDs are crystals; LCDs are highly structured; OLEDs are not –
Malleable; can be bent, rolled up, etc.
Easier to fabricate

In general, OLED research proceeds on many fronts
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29-09-2010, 10:53 AM


.doc   MY OLED.doc (Size: 100.5 KB / Downloads: 210)
ORGANIC LIGHT EMITTING DIODE (OLED)


ABSTRACT
During the last two decades, organic light-emitting diodes (OLEDs) have attracted considerable interest owing to their promising applications in flat-panel displays by replacing cathode ray tubes (CRTs) or liquid crystal displays (LCDs).
Electroluminescence is the emission of light from materials in an electric field, and in the 1960s this phenomenon was observed from single crystals of anthracene. Despite the high quantum efficiency obtained with such organic crystals, no application has emerged owing to the high working voltage required as a result of the large crystal thickness and poor electrical contact quality. Nevertheless, these studies have led to a good understanding of the basic physical processes involved in organic electroluminescence, i.e. charge injection, charge transportation, exciton formation and light emission.
The need for new lightweight, low-power, wide viewing angled, handheld portable communication devices have pushed the display industry to revisit the current flat-panel digital display technology used for mobile applications.
A first breakthrough was achieved in 1987 by Tang and Van Slyke from Kodak when they reported efficient and low-voltage OLEDs from p-n heterostructure devices using thin films of vapour-deposited organic materials.
Struggling to meet the needs of demanding applications such as e-books, smart networked household appliances, identity management cards, and display-centric handheld mobile imaging devices, the flat panel industry is now looking at new displays known as Organic Light Emitting Diodes (OLED).

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14-10-2010, 12:12 PM


.ppt   Presentation on oled.ppt (Size: 3.53 MB / Downloads: 264)




ABSTRACT

Organic light emitting diode (OLED) display technology has been grabbing headlines in recent years. Now one form of OLED displays, LIGHT EMITTING POLYMER (LEP) technology is rapidly emerging as a serious candidate for next generation flat panel displays. LEP technology promises thin, light weight emissive displays with low drive voltage, low power consumption, high contrast, wide viewing angle, and fast switching times.
One of the main attractions of this technology is the compatibility of this technology with plastic-substrates and with a number of printer based fabrication techniques, which offer the possibility of roll-to-roll processing for cost-effective manufacturing.
LEPs are inexpensive and consume much less power than any other flat panel display. Their thin form and flexibility allows devices to be made in any shape. One interesting application of these displays is electronic paper that can be rolled up like newspaper.
Cambridge Display Technology, the UK, is betting that its light weight, ultra thin light emitting polymer displays have the right stuff to finally replace the bulky, space consuming and power-hungry cathode ray tubes (CRTs) used in television screens and computer monitors and become the ubiquitous display medium of the 21st century.

INTRODUCTION
Light emitting polymers or polymer based light emitting diodes discovered by Friend et al in 1990 has been found superior than other displays like, liquid crystal displays (LCDs) vacuum fluorescence displays and electro luminescence displays. Though not commercialised yet, these have proved to be a mile stone in the filed of flat panel displays. Research in LEP is underway in Cambridge Display Technology Ltd (CDT), the UK.
In the last decade, several other display contenders such as plasma and field emission displays were hailed as the solution to the pervasive display. Like LCD they suited certain niche applications, but failed to meet broad demands of the computer industry.


Reference: topicideashow-to-organic-light-emitting-diode-oled-seminar and presentation-report#ixzz12JOtNxV8
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16-10-2010, 05:07 PM


.docx   Organic Electro-Luminescence.docx (Size: 1.07 MB / Downloads: 150)
This article is presented by:
K.SUMANTH
K.V.CHANUKYA
Organic Electro-Luminescence


Introduction:
An organic light emitting diode (OLED) is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compounds which emits light in response to an electric current. This layer of organic semiconductor material is sandwiched between two electrodes. Generally, at least one of these electrodes is transparent.
OLEDs are used in television screens, computer monitors, small, portable system screens such as mobile phones and PDAs, watches, advertising, information and indication; they can also be used in light sources for general space illumination and in large-area light-emitting elements. Due to their comparatively early stage of development, they typically emit less light per unit area than inorganic solid-state based LEDs point-light sources.
An OLED display functions without a backlight. Thus, it can display deep black levels and can be thinner and lighter than established liquid crystal displays. Similarly, in low ambient light conditions such as dark rooms, an OLED screen can achieve a higher contrast ratio than an LCD screen using either cold cathode fluorescent lamps or the more recently developed LED backlight.
There are two main families of OLEDs. These are 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.
OLED displays can use either passive-matrix or active-matrix addressing schemes. Active-matrix OLEDs (AMOLED) require a thin-film transistor backplane to switch each individual pixel on or off, and can make higher resolution and larger size displays possible.
What is an OLED:
Organic Light Emitting Diode, or OLED, is a technology that uses carbon-based organic material in a process that converts electric energy into light. This light is used to illuminate the screen and produce the most astounding results ever seen on a Display.

Like an LED, an OLED is a solid-state semiconductor device that is 100 to 500 nanometers thick or about 200 times smaller than a human hair. OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. In this article, we'll be focusing on the two-layer design
How do OLEDs work?


An OLED is made by placing a series of organic thin films between two conductors. When electrical current is applied, a bright light is emitted. An OLED is made by placing a series of organic thin films between two conductors. When electrical current is applied, a bright light is emitted.
Types of OLEDs:
There are several types of OLEDs,
• Passive-matrix OLED
• Active-matrix OLED
• Transparent OLED
• Top-emitting OLED
• Foldable OLED
• White OLED
Each type has different uses.
Passive-matrix OLED (PMOLED):
PMOLEDs have strips of cathode, organic layers and strips of anode. The anode strips are arranged perpendicular to the cathode strips. The intersections of the cathode and anode make up the pixels where light is emitted. External circuitry applies current to selected strips of anode and cathode, determining which pixels get turned on and which pixels remain off. Again, the brightness of each pixel is proportional to the amount of applied current.

PMOLEDs are easy to make, but they consume more power than other types of OLED, mainly due to the power needed for the external circuitry. PMOLEDs are most efficient for text and icons and are best suited for small screens (2- to 3-inch diagonal) such as those you find in cell phones, PDAs and MP3 players. Even with the external circuitry, passive-matrix OLEDs consume less battery power than the LCDs that currently power these devices.

Active-matrix OLED (AMOLED) :

AMOLEDs have full layers of cathode, organic molecules and anode, but the anode layer overlays a thin film transistor (TFT) array that forms a matrix. The TFT array itself is the circuitry that determines which pixels get turned on to form an image.

AMOLEDs consume less power than PMOLEDs because the TFT array requires less power than external circuitry, so they are efficient for large displays. AMOLEDs also have faster refresh rates suitable for video. The best uses for AMOLEDs are computer monitors, large-screen TVs and electronic signs or billboards.
Transparent OLED :
Transparent OLEDs have only transparent components (substrate, cathode and anode) and, when turned off, are up to 85 percent as transparent as their substrate. When a transparent OLED display is turned on, it allows light to pass in both directions. A transparent OLED display can be either active- or passive-matrix. This technology can be used for heads-up displays.

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19-10-2010, 02:53 PM



.ppt   OLED 2.ppt (Size: 3.32 MB / Downloads: 214)
Organic Light Emitting Diodes and Displays
Miss Aastha .M. Gupta
Instructed by: Komal Goenka


Contents


Introduction
Birth of OLEDs
Current OLEDs
Different types of OLEDs
Advancements
Future of OLEDs
Conclusion

Introduction

Technology based on electroluminescence
Light is emitted when current flows through organic material
Luminescent materials have great potential
Fireflies utilize process with nearly 100% efficiency

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03-03-2011, 03:16 PM

Presented By:
PRATYUSH MISHRA


.ppt   PRATYUSH PPT-OLED.ppt (Size: 4.02 MB / Downloads: 195)
What is an OLED?
OLED - Organic Light Emitting Diode

An OLED is any light emitting diode (LED) in which emissive electroluminescent layer is film of organic compounds.
 Birth of OLEDs
 First successfully created by Ching Tang and Steve Van Slyke in 1987 at Kodak Labs.
 First tests – very efficient, simple to make
 Showed potential for displays
History of OLEDs
 First developed in the early 1950s in France
Architecture of OLEDs
 SUBSTRATE
 ANODE
 CONDUCTING LAYER
 EMISSIVE LAYER
 CATHODE
How OLED Works
1. Voltage applied across Cathode and Anode
1. Typically 2V-10V
2. Current flows from cathode to anode
1. Electrons flow to emissive layer
2. Electrons removed from conductive layer leaving holes
3. Holes jump into emissive layer
3. Electron and hole combine and light emitted
Types of OLEDs
 Passive-matrix OLED
 Active-matrix OLED
 Transparent OLED
 Top-emitting OLED
 Foldable OLED
 White OLED
 1. Passive-Matrix OLED (PMOLED)
 Perpendicular cathode/anode strip orientation
 Light emitted at intersection (pixels)
 External circuitry
 Turns on/off pixels
 External circuitry
 Large power consumption
 Used on 1-3 inch screens
 Alphanumeric displays
 2. Active-Matrix OLED
(AMOLED)
 Full layers of cathode, anode, organic molecules
 Thin Film Transistor matrix (TFT) on top of anode
 Internal circuitry to determine which pixels to turn on/off
 Less power consumed then PMOLED
 Used for larger displays
 3. Transparent OLED
TOLED
 Transparent substrate, cathode and anode
 Bi-direction light emission
 Passive or Active Matrix OLED
 Useful for heads-up display
 Transparent project and implimentationor screen
 glasses
 4. Top-emitting OLED
TEOLED
 Non-transparent or reflective substrate
 Transparent Cathode
 Used with Active Matrix Device
 Smart card displays
 5. Foldable OLED
 Flexable metalic foil or plastic substrate
 Lightweight and durable
 Clothing OLED
 6. White OLED
 Emits bright white light
 Replace fluorescent lights
 Reduce energy cost for lighting
 Advantages of OLEDs
 Much faster response time
 Consume significantly less energy
 Able to display "True Black" picture
 Thinner display
 Better contrast ratio
 Safer for the environment
 OLEDs refresh almost 1,000 times faster then LCDs
 New design concepts for interior lighting
 Disadvantages of OLEDs
 Cost to manufacture is high
 Easily damaged by water
 Limited market availability
 Not as easy as changing a light bulb
 Current Research for OLEDs
• Manufacturers focusing on finding a cheap way to produce
o "Roll-to-Roll" Manufacturing
• Increasing efficiency of blue luminance
 Applications of OLEDs
• TVs
• Cell Phone screens
• Computer Screens
• Keyboards (Optimus Maximus)
• Lights
• Portable Device displays
 OLEDs as a Light Source
 OLED Televisions
• Released XEL-1 in February 2009.
• First OLED TV sold in stores.
• 11'' screen, 3mm thin
• Weighs approximately 1.9 kg
• Wide 178 degree viewing angle
• Optimus Maximus Keyboard
Lighting
• Flexible / bendable lighting
• Wallpaper lighting defining new ways to light a space
• Transparent lighting doubles as a window
Cell Phones
• Nokia 888
Future Uses for OLED
Transparent Car Navigation System on Windshield
• Using Samsungs' transparent OLED technology
Scroll Laptop
• Nokia concept OLED Laptop



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09-03-2011, 04:41 PM

Submitted by
Deepika Jaswal


.docx   SEMINAR REPORT-Print.docx (Size: 2.52 MB / Downloads: 139)
ABSTRACT
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry.
1.0 INTRODUCTION
Since the breakthrough by Kodak in 1987, organic light-emitting diodes (OLEDs) have been seen as one of the most promising technologies for future displays. Like an LED, an OLED is a solid-state semiconductor device that is 100 to 500 nanometers thick or about 200 times smaller than a human hair.
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry. The circuitry for driving the pixels can be adapted to the OLED, sometimes at the expense of the simplicity of the display, but bearing in mind that the fabrication process must remain industrially viable.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
Emerging organic light emitting diode (OLED) based displays obviate external lighting; and consume drastically different power when displaying different colors, due to their emissive nature. This creates a pressing need for OLED display power models for system energy management, optimization as well as energy efficient GUI design, given the display content or even the graphical user interface (GUI) code.
2.0 HISTORY
These were first developed in the early 1950’s in France by applying a high-voltage alternating current field to crystalline thin films of acridine orange and quinacrine. The first diode device with organic materials was invented at Eastman Kodak in the 1980’s by Dr. Ching Tang and Steven Van Slyke.
Today OLED is used in television screens, computer displays, portable system screens, advertising, information and indication. It is also used in light sources for general space illumination, and large-area light-emitting elements.
3.0 BASIC OF ORGANIC SEMICONDUCTORS:
(STRUCTURE AND GRAPHS)

In the figures below , figure a and b show Locus electrical curves of the OLET in n-polarization in figure (a)while (b) shows p-polarization.
During the n-polarization the electroluminescence output power (magenta) is also collected. Figure c shows the transfer characteristic curves, the source–drain current (IDS) is measured keeping the drain–source potential constant at 90 V, while sweeping the gate-source potential from 0 to 90 V.
In figure d, AFM image of a 7-nm-thick DFH-4T film grown on glass/ITO/PMMA substrate.
e, AFM image of a 40-nm-thick film of Alq3Sad3%)DCM blend grown on top of the DFH-4T thin film reported in d. f, AFM image of a 15-nm-thick DH-4T film grown on top of the Alq3Sad3%)DCM film reported in e. For ease of comparison the same z-axis colour scale is used for both images e and
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26-03-2011, 12:18 PM


.docx   oled report.docx (Size: 196.52 KB / Downloads: 79)
INTRODUCTION
An organic light emitting diode (OLED) is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes. Generally, at least one of these electrodes is transparent.
OLEDs are used in television screens, computer monitors, small, portable system screens such as mobile phones and PDAs, watches, advertising, information and indication. OLEDs are also used in light sources for space illumination and in large-area light-emitting elements. Due to their early stage of development, they typically emit less light per unit area than inorganic solid-state based LED point-light sources.
An OLED display functions without a backlight. Thus, it can display deep black levels and can be thinner and lighter than liquid crystal displays. In low ambient light conditions such as dark rooms, an OLED screen can achieve a higher contrast ratio than an LCD using either cold cathode fluorescent lamps or the more recently developed LED backlight.
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.
OLED displays can use either passive-matrix (PMOLED) or active-matrix addressing schemes. Active-matrix OLEDs (AMOLED) require a thin-film transistorbackplane to switch each individual pixel on or off, and can make higher resolution and larger size displays possible.
The first observations of electroluminescence in organic materials were in the early 1950s by A. Bernanose and co-workers at the Nancy-Université, France. They applied high-voltage alternating current(AC) fields in air to materials such as acridine orange, either deposited on or dissolved in cellulose or cellophane thin films. The proposed mechanism was either direct excitation of the dye molecules or excitation of electrons.
In 1960, Martin Pope and co-workers at New York University developed ohmic dark-injecting electrode contacts to organic crystals. They further described the necessary energetic requirements (work functions) for hole and electron injecting electrode contacts. These contacts are the basis of charge injection in all modern OLED devices. Pope's group also first observed direct current (DC) electroluminescence under vacuum on a pure single crystal of anthracene and on anthracene crystals doped with tetracene in 1963 using a small area silver electrode at 400V. The proposed mechanism was field-accelerated electron excitation of molecular fluorescence.
Pope's group reported in 1965 that in the absence of an external electric field, the electroluminescence in anthracene crystals is caused by the recombination of a thermalized electron and hole, and that the conducting level of anthracene is higher in energy than the exciton energy level. Also in 1965, W. Helfrich and W. G. Schneider of the National Research Council in Canada produced double injection recombination electroluminescence for the first time in an anthracene single crystal using hole and electron injecting electrodes, the forerunner of modern double injection devices. In the same year, Dow Chemical researchers patented a method of preparing electroluminescent cells using high voltage (500–1500 V) AC-driven (100–3000 Hz) electrically-insulated one millimetre thin layers of a melted phosphor consisting of ground anthracene powder, tetracene, and graphite powder. Their proposed mechanism involved electronic excitation at the contacts between the graphite particles and the anthracene molecules.
Device performance was limited by the poor electrical conductivity of contemporary organic materials. This was overcome by the discovery and development of highly conductive polymers. For more on the history of such materials, see conductive polymers.
Electroluminescence from polymer films was first observed by Roger Partridge at the National Physical Laboratory in the United Kingdom. The device consisted of a film of poly(n-vinylcarbazole) up to 2.2 micrometres thick located between two charge injecting electrodes. The results of the project and implimentation were patented in 1975 and published in 1983.
The first diode device was reported at Eastman Kodak by Ching W. Tang and Steven Van Slyke in 1987. This device used a novel two-layer structure with separate hole transporting and electron transporting layers such that recombination and light emission occurred in the middle of the organic layer. This resulted in a reduction in operating voltage and improvements in efficiency and led to the current era of OLED research and device production.
Research into polymer electroluminescence culminated in 1990 with J. H. Burroughes et al. at the Cavendish Laboratory in Cambridge reporting a high efficiency green light-emitting polymer based device using 100 nm thick films of poly(p-phenylene vinylene).
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27-04-2011, 02:26 PM


Presented by:
Syed Umar Farooq
V.Satya Dilip Rama Raju


.doc   OLED_Organic.doc (Size: 719.5 KB / Downloads: 118)
Abstract
If ever a technology has begged to be disrupted, it is Liquid Crystal Displays. Invented in 1963 and envisioned as a slimmed-down replacement for bulky cathode ray tubes or as screens for wall mounted televisions – a use never realized due to problems scaling up to large surfaces – liquid crystal displays have instead become the standard for everything from watches to laptop computers. Despite this, however, remains high production and commercial expenses that have never come down enough to successfully mass market these displays, leaving the technology vulnerable to new innovations.
With the imaging appliance revolution underway, the need for more advanced handheld devices that will combine the attributes of a computer, PDA, and cell phone is increasing and the flat-panel mobile display industry is searching for a display technology that will revolutionize the industry. The need for new lightweight, low-power, wide viewing angled, handheld portable communication devices have pushed the display industry to revisit the current flat-panel digital display technology used for mobile applications. Struggling to meet the needs of demanding applications such as e-books, smart networked household appliances, identity management cards, and display-centric handheld mobile imaging devices, the flat panel industry is now looking at new displays known as Organic Light Emitting Diodes (OLED).
What Is Organic Light Emitting Diodes (OLED)?
Organic Light Emitting Diode technology, pioneered and patented by Kodak/Sanyo, enables full color, full-motion flat panel displays with a level of brightness and sharpness not possible with other technologies.
Unlike traditional LCD’s, OLED’s are self-luminous and do not require backlighting, diffusers, polarizers, or any of the other baggage that goes with liquid crystal displays. Essentially, the OLED consists of two charged electrodes sandwiched on top of some organic light emitting material. This eliminates the need for bulky and environmentally undesirable mercury lamps and yields a thinner, more versatile and more compact display. Their low power consumption provides for maximum efficiency and helps minimize heat and electric interference in electronic devices. Armed with this combination of features, OLED displays communicate more information in a more engaging way while adding less weight and taking up less space.
There are two forms of OLED displays: Passive-matrix and Active-matrix.
Passive Displays:
The passive-matrix OLED display has a simple structure and is well suited for low-cost and low-information content applications such as alphanumeric displays. It is formed by providing an array of OLED pixels connected by intersecting anode and cathode conductors.
Organic materials and cathode metal are deposited into a “rib” structure (base and pillar), in which the rib structure automatically produces an OLED display panel with the desired electrical isolation for the cathode lines. A major advantage of this method is that all patterning steps are conventional, so the entire panel fabrication process can easily be adapted to large-area, high-throughput manufacturing.
To get a passive-matrix OLED to work, electrical current is passed through selected pixels by applying a voltage to the corresponding rows and columns from drivers attached to each row and column. An external controller circuit provides the necessary input power, video data signal and multiplex switches. Data signal is generally supplied to the column lines and synchronized to the scanning of the row lines. When a particular row is selected, the column and row data lines determine which pixels are lit. A video output is thus displayed on the panel by scanning through all the rows successively in a frame time, which is typically 1/60 of a second.
Active Displays:
In contrast to the passive-matrix OLED display, active-matrix OLED has an integrated electronic back plane as its substrate and lends itself to high-resolution, high-information content applications including videos and graphics. This form of display is made possible by the development of polysilicon technology, which, because of its high carrier mobility, provides thin-film-transistors (TFT) with high current carrying capability and high switching speed.
In an active-matrix OLED display, each individual pixel can be addressed independently via the associated TFT’s and capacitors in the electronic back plane. That is, each pixel element can be selected to stay “on” during the entire frame time, or duration of the video. Since OLED is an emissive device, the display aperture factor is not critical, unlike LCD displays where light must pass through aperture.
Therefore, there are no intrinsic limitations to the pixel count, resolution, or size of an active-matrix OLED display, leaving the possibilities for commercial use open to our imaginations. Also, because of the TFT’s in the active-matrix design, a defective pixel produces only a dark effect, which is considered to be much less objectionable than a bright point defect, like found in LCD’s.
How It Works:
The basic OLED cell structure consists of a stack of thin organic layers sandwiched between a transparent anode and a metallic cathode. The organic layers comprise a hole-injection layer, a hole-transport layer, an emissive layer, and an electron-transport layer. When an appropriate voltage (typically between 2 and 10 volts) is applied to the cell, the injected positive and negative charges recombine in the emissive layer to produce light (electro luminescence). The structure of the organic layers and the choice of anode and cathode are designed to maximize the recombination process in the emissive layer, thus maximizing the light output from the OLED device.
Advantages:
 Robust Design - OLED’s are tough enough to use in portable devices such as cellular phones, digital video cameras, DVD players, car audio equipment and PDA’s.
 Viewing Angles – Can be viewed up to 160 degrees, OLED screens provide a clear and distinct image, even in bright light.
 High Resolution – High information applications including videos and graphics, active-matrix OLED provides the solution. Each pixel can be turned on or off independently to create multiple colors in a fluid and smooth edged display.
 “Electronic Paper” – OLED’s are paper-thin. Due to the exclusion of certain hardware goods that normal LCD’s require, OLED’s are as thin as a dime.
o Production Advantages – Up to 20% to 50% cheaper than LCD processes. Plastics will make the OLED tougher and more rugged. The future quite possibly could consist of these OLED’s being produced like newspapers, rather than computer “chips”.
o Video Capabilities – They hold the ability to handle streamlined video, which could revolutionize the PDA and cellular phone market.
o Hardware Content – Lighter and faster than LCD’s. Can be produced out of plastic and is bendable. Also,OLED’s do not need lamps, polarizers, or diffusers.
o Power Usage – Takes less power to run (2 to 10 volts).
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28-04-2011, 11:56 AM


Presented by
Bhoopendra singh


.ppt   OLED_Organic.ppt (Size: 1.14 MB / Downloads: 121)
OLED (Organic Light Emitting Diode)
What is an OLED?
OLED - Organic Light Emitting Diode

An OLED is any light emitting diode (LED) which emissive electroluminescent layer is composed of a film of organic compounds.
History of OLEDs
First developed in the early 1950s in France
Early technology would emmite a short burst of light when a voltage was applied
This early form applied high-voltage alternating current field to crystalline thin films of acridine orange and quinacrine.
Architecture of OLEDs
Substrate (clear plastic, glass, foil) - The substrate supports the OLED.
Anode (transparent) - The anode removes electrons (adds electron "holes") when a current flows through the device.
Types of OLEDs
Passive OLEDs
The organic layer is between strips of cathode and anode that run perpendicular
The intersections form the pixels
 Easy to make
Use more power
Best for small screens
Active OLEDs
Full layers of cathode and anode
 Anode over lays a thin film transistor (TFT)
Requires less power
Higher refresh rates
Suitable for large screens
Current Research for OLEDs
Manufacturers focusing on finding a cheap way to produce
"Roll-to-Roll" Manufacturing
Increasing efficiency of blue luminance 
  Boosting overall lifespan
Applications of OLEDs
TVs
Cell Phone screens
Computer Screens
Keyboards (Optimus Maximus)
Lights
Portable Divice displays
OLEDs as a Light Source
OLED Televisions
Released XEL-1 in February 2009. 
First OLED TV sold in stores.
11'' screen, 3mm thin
$2,500 MSRP
Weighs approximately 1.9 kg
Wide 178 degree viewing angle
1,000,000:1 Contrast ratio
Optimus Maximus Keyboard
Advantages of OLEDs
Much faster response time
Consume significantly less energy
Able to display "True Black" picture
Wider viewing angles
Thinner display
Better contrast ratio
Safer for the environment
Has potential to be mass produced inexpensively
OLEDs refresh almost 1,000 times faster then LCDs
Disadvantages of OLEDs
OLED Displays Vs. LCD and Plasma
Cost to manufacture is high
Overall luminance degradation
Constraints with lifespan 
Easily damaged by water
Limited market availability
OLED Lighting Vs. Incandescent and Fluorescent 
Not as easy as changing a light bulb
Future Uses for OLED
Lighting
Flexible / bendable lighting
Wallpaper lighting defining new ways to light a space
Transparent lighting doubles as a window
Future Uses for OLED
Transparent Car Navigation System on Windshield
Using Samsungs' transparent OLED technology
Heads up display 
GPS system 
Scroll Laptop
Nokia concept OLED Laptop
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02-05-2011, 04:15 PM

Presented By
Paulomi Deekonda


.pdf   29784957-OLED-1.pdf (Size: 370.3 KB / Downloads: 106)
ABSTRACT
Organic Light-emitting Diodes (OLEDs) are just like a movie project and implimentationor screen in theearlier times with a thin sheet hanged on the wall in which the screen was light, paperthinand could be rolled into portable tube. The materials used in OLEDs need not becrystalline that is composed of a precisely repeating pattern of planes of atoms, so theyare easier to make. They are applied in thin layers for slimmer profiles and differentmaterials for different colours that can be patterned on a given substrate for making highresolution images. In the coming years, large screen televisions or computer monitorscould roll up for storage. A soldier might unfurl a sheet of plastic showing a real timesituation map. Smaller displays could be wrapped around a person’s forearms orincorporated into clothing. The OLED panels could curl around an architectural columnor lay almost wall paper like against a wall or ceiling.
ORGANIC LIGHT - EMITTING DIODES
1. INTRODUCTION:
An organic light emitting diode (OLED) is simply a light emitting diode (LED) whoseemissive electro luminescent layer is composed of a film of organic compounds. The layersare made up of small organic molecules or macro polymers that conduct electricity. Theyhave conductivity levels ranging from insulators to conductors, so OLEDs are considered asorganic semiconductors. The layer of organic semiconductor material is formed between twoelectrodes, where at least one of the layers is transparent.
2. SURFACE CONSTRUCTION OF OLED ILLUMINATION:
It consists of an emissive layer, a conductive layer, a substrate, and both anode and cathodeterminals. The emissive layer, where light is made by the emission of radiation whosefrequency is in the visible region is made up of organic plastic molecules that transportelectrons from the cathode and the polymer used is polyfluorene. The conductive layer ismade up of organic plastic molecules that transport holes from the anode and the conductingpolymer used is polyaniline. The substrate that supports OLED is made up of flexible plastic,inexpensive glass or metal foil. Anode, that removes electrons when a current flows throughthe device, is generally made up of Indium tin oxide and it is transparent and cathode thatinjects electrons when a current flows through the device is made up of metals likealuminium and calcium, which may or may not be transparent depending on the type ofOLED.4OLED structure
3. LIGHT EMISSION PRINCIPLE :
OLEDs emit light in a similar manner to LEDs, through a process called electrophosphorescence.An electrical current flows from the cathode to the anode through theorganic layers. When a voltage is applied to OLED, the holes and the electrons are generatedfrom each of the two electrodes, which have a positive and negative electric chargerespectively. When they recombine in the emissive layer, organic materials make theemissive layer to turn into a high energy state termed “excitation”. The light is emitted whenthe layer returns to its original stability. The molecular structure of organic materials haslimitless combinations, each of which varies in its colour and durability. Within theselimitless combinations, identifying organic materials that provide high efficiency and longlife will determine its practical application.A semi-conducting material such as silicon has an energy gap between its lower, filledelectrons state called as valence band and its upper, unfilled electrons state called asconduction band. As electrons drop to the lower state and occupy holes, photons of visiblelight are emitted. The colour of the light depends on the type of organic molecule in theemissive layer and the intensity or brightness of the light depends on the amount of electricalcurrent applied.
4. CREATION OF COLOUR
OLED has more control over colour expression because it only expresses pure colours whenelectric current stimulates the relevant pixels. The primary colour matrix is arranged in red,green and blue pixels which are mounted directly to a printed circuited board. Eachindividual OLED element is housed in a special micro cavity structure designed to greatlyreduce ambient light interference that also improves overall colour contrast. The thickness ofthe organic layer is adjusted to produce the strongest light to give a colour picture. Further,the colours are refined with a filter and purified without using a polarizer to give outstandingcolour purity.
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