OLED TECHNOLOGY

INTRODUCTION

Uses organic light emitting diode(OLED).

Emerging Technology for displays in devices.

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 is100 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.

HISTORY

The first OLED device was developed by

Eastman Kodak in 1987.

In 1996, pioneer produces the world’s first

commercial PMOLED.

In 2000, many companies like Motorola, LG

etc developed various displays.

In 2001, Sony developed world’s largest

fullcolor OLED.

HISTORY (CONTD.)

In 2002, approximately 3.5 million passive

matrix OLED sub-displays were sold, and

over 10 million were sold in 2003.

In 2010 and 2011, many companies

announced AMOLED displays.

Many developments had take place in the

year 2012.

FEATURES

Flexibility.

Emissive Technology.

Light weight and thin.

Low power consumption.

High contrast, brighter and perfect display

from all angles.

STRUCTURE OF OLED

Substrate.

Anode.

Organic layer.

-Conductive layer (Hole Transport Layer).

made up of polyaniline or metal-phthalocyanine.

-Emissive layer( Electron Transport Layer).

made up of polyfluorene or metal chelates.

Cathode.

STRUCTURE OF OLED(FIGURE)

OLED FABRICATION

Substrate preparation.

Device deposition Deposit and pattern anode.

Pattern organic layers.

Vacuum deposit and pattern cathode.

Encapsulation.

Also involves making backplane.

OLED DEPOSITION

Organic layers can be applied to the

substrate using the following methods.

- Evaporation and shadow masking.

- Inkjet printing.

- Organic vapor phase deposition.

EVAPORATION AND SHADOW MASKING

INKJET PRINTING

ORGANIC VAPOR PHASE DEPOSITION

COLOUR GENERATION

Different approaches for fabricating red,

green and blue pixels.

- Red, green and blue individual pixels.

- White emitter and colour filters.

- Blue emitter and colour converters.

- Stacked OLED

COLOUR GENERATION(FIGURE)

WORKING PRINCIPLE

A voltage is applied across the anode and cathode.

Current flows from cathode to anode through the

organic layers.

Electrons flow to emissive layer from the cathode.

Electrons are removed from conductive layer

leaving holes.

Holes jump into emissive layer .

Electron and hole combine and light emitted.

WORKING PRINCIPLE(FIGURE)

OLED DEVICE OPERATION

Transparent substrate

Anode(ITO)

Conductive layer

Emissive layer

Cathode

LUMO

LUMO

HOMO

HOMO

eˉ

eˉ

h+

h+

h+

Light

TYPES OF OLED

Six types of OLEDs

Passive matrix OLED(PMOLED).

Active matrix OLED(AMOLED).

Transparent OLED(TOLED).

Top emitting OLED.

Flexible OLED(FOLED).

White OLED(WOLED).

PASSIVE MATRIX OLED

ACTIVE MATRIX OLED

TRANSPARENT OLED

TOP EMITTING OLED

FLEXIBLE OLED

WHITE OLED

OLED ADVANTAGES

Thinner, lighter and more flexible.

Do not require backlighting like LCDs.

Can be made to larger sizes.

Large fields of view, about 170 degrees.

Faster response time.

Brighter.

High resolution, <5μm pixel size. 

OLED DISADVANTAGES

Expensive.

Lifespan.

Water damage.

Colour balance issues .

OLED VS. LCD

Greater view angle. High contrast. Faster response

time. Do not require

backlighting. Temperature(~50°C

– 80°C).

Limited view angle. Low contrast. Slow response time. Require

backlighting. Temperature(~0°C-

100°C).

OLED LCD

APPLICATIONS

Major applications of OLED technology are

OLED TV.

Mobile phones with OLED screens.

Rolltop Laptop.

OLED TV

MOBILE PHONES WITH OLED SCREEN

ROLLTOP LAPTOP

CONCLUSION

Organic Light Emitting Diodes are evolving as

the next generation displays.

As OLED display technology matures, it will

be better able to improve upon certain

existing limitations of LCD including

high power consumption

limited viewing angles

poor contrast ratios.