OLED Architecture

• Cathode: The cathode injects electrons into emissive layer.
• Emissive layer: This layer is made of polyfluorene that transport electrons from the cathode. This is where light is made.
• Conducting layer: This layer is made of polyaniline that transport "holes" from the anode.
• Anode: It is kept transparent. Usually made up of Indium tin oxide (ITO) that removes electrons.
• Substrate: The substrate supports the OLED.

Oled Structure

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

Display & Pixel Structure

Pixel

Display

Types of OLEDs

• Organic Light Emitting Diode (OLED)
• Light Emitting polymers (LEP)

Types of OLEDs

• Passive-matrix OLED
• Active-matrix OLED
• Transparent OLED
• Top-emitting OLED
• Foldable OLED
• White OLED

Passive-matrix OLED

• Perpendicular cathode/anode strip orientation
• Light emitted at intersections(pixels)
• Easy to make
• Large power consumption
• Best for small screens

Active-matrix OLED

• Full layers of cathode and anode
• Anode overlays a TFT
• Requires less power
• Suitable for large screens
• Newer AMOLED technologies
  • Super AMOLED
  • Super Amoled Plus
  • Super AMOLED HD

Transparent OLED

• Transparent substrate,cathode and anode
• Emits light bi-directionally
• Passive or Active matrix OLED
• Useful for head-up displays
• Transparent projector screens
• Glasses

Top-Emitting OLED

• Non Transparent or reflective substrate
• Transparent cathode
• Used with Active matrix device
• Smart Card displays

Foldable OLED

• Substrates made of very flexible metallic foils or plastics
• Very lightweight and durable reduces breakage
• Attached to fabrics to create "smart" clothing

WHite OLED

• Emits bright white light.
• Replace fluorescent lights.
• Reduce energy cost for lighting.
• True Color Qualities.

advantages

• Thinner, lighter and more flexible.
• Plastic substrates rather then glass.
• Able to display "True Black" picture
• High resolution (<5um pixel size) and fast switching (1-10um).
• Do not require backlight, light generated.
• Low voltage, low power and emissive source.
• Larger sized displays.
• Brighter- good day light visibility.
• Larger viewing angles -170°
• Safer for environment

Disadvantages

• Lifetime
  • White, Red, Green 46,000-230,000 hours.
    • About 5-25 years.
  • Blue 14,000 hours.
    • About 1.6 years.
• Expensive.
• Manufactoring
• Susceptible to water.
• Overcome multi-billion dollar LCD market.