Under The Guidance ofUnder The Guidance ofDr. Sudhanshu ChoudharyDr. Sudhanshu Choudhary

Presented by ,Purval G. Patel (3136619)

Outline

What Is an OLED? Architecture of OLEDs. How OLED emit light. Types of OLEDs. Advantages & Disadvantages. Future Use. References.

INTRODUCTION

OLED - Organic Light Emitting Diode

Emerging Technology for displays devices.

Uses organic light emitting diode(OLED).

Main principle behind OLED technology is electroluminescence.

Offers brighter, thinner, high contrast, flexible displays.

.

What is an OLED?

OLEDs are solid state devices composed of thin films of

organic molecules that is 100 to 500 nanometres thick.

They emits light with the application of electricity.

They doesn’t require any backlight. i.e., they are self

emitting.

They are made from carbon and hydrogen.

Architecture of OLEDs

1. Substrate.

2. Anode.

3. Organic layer.

-Conductive layer

(Hole Transport Layer).

-Emissive layer

( Electron Transport Layer).

4. Cathode.

How OLEDs Emit Light

• The battery or power supply of the device containing the OLED applies a voltage across the OLED.

• An electrical current flows from the cathode to the anode through the organic layers.

• At the boundary between the emissive and the conductive layers, electrons find electron holes.

• The OLED emits light.

Color Generation

Types of OLEDs

Passive-matrix OLED.

Active-matrix OLED.

Transparent OLED.

Top-emitting OLED.

Flexible OLED.

Passive-Matrix OLED

• The organic layer is between cathode & anode stripes which run perpendicular.

• The intersections form the pixels.

• Easy to make.

• Use more power.

• Best for small screens.

Active-Matrix OLED

• Full layers of cathode .

• Anode over lays a thin film transistor (TFT).

• Requires less power.

• Higher refresh rates.

• Suitable for large screens

Transparent OLED

• Transparent substrate, cathode and anode.

• Bi-direction light emission.

• Passive or Active Matrix OLED. • Useful for heads-up display.

• Transparent projector screen, glasses.

Top-Emitting OLED

• Top-emitting OLEDs have a substrate that is either opaque or reflective.

• Transparent Cathode.

• Used with Active Matrix Device.

• Smart card displays.

Flexible OLED

• Flexible metallic foil or plastic substrate.

• Light weight and ultra thin. • Reduce display breaking.

• Ex. Samsung’s YOUM Display.

How LCD Works?

Advantages of OLED• Faster response time than LCDs .

• Consume significantly less energy .

• Can be transparent when off.

• Flexible and Conformal Displays .

• Thinner display-No backlight required.

• Better contrast ratio.

• Safer for the environment.

• Wider viewing angles; up to 170 degrees.

• OLEDs refresh almost 1,000 times faster then LCDs.

• Low cost materials.

• Can be made using plastic screens; LCDs require glass backing.

Difference between LCD, Plasma And OLED

Fast Response Time

OLED LCD

Constant Contrast Ratio – wide viewing angle

Disadvantages of OLEDs

OLED seems to be the perfect technology for all types of displays, but it also has

some problems:

• Lifetime - While red and green OLED films have longer lifetimes (46,000 to 230,000

hours), blue organics currently have much shorter lifetimes (up to around 14,000

hours)

• Manufacturing - Currently, manufacturing is more expensive than LCDs

• Water - Water can easily damage OLEDs

• OLED screens are even worse than LCD in direct sunlight.

• Limited market availability

 

Future Uses for OLED

• Curved OLED displays, placed on non-flat surfaces.

• Wearable OLEDs.

• Transparent OLEDs embedded in windows.

• OLEDs in car windshields.

• New designs for lamps.

References Kunic, S. ; Sego, Z. “OLED technology and displays” IEEE Publication Year: 2012 , Page(s):

31 – 35.

Wen, Shih-Wen ; Lee, Meng-Ting ; Chen, Chin H. ” Recent  development  of  blue fluorescent OLED  materials  and  devices” IEEE Display Technology, Journal. Publication Year: 2005 , Page(s): 90 - 99

http://electronics.howstuffworks.com/oled.html

http://www.oled-info.com

Thank You