OLED TV Display - What, How and Why?

What is an OLED?

OLED stands for Organic Light Emitting Diode.

OLEDs are special because they are made up of organic polymer molecules (otherwise known as plastic) allowing light to emit when a voltage is applied. Large displays can be simply 'printed' in the manufacturing process allowing production of a large display matrix far easier than a regular LED equivalent.

Benefits of OLED displays. Why?

Light Emitting Diodes have the ability to produce bright light, from a wider area with very little heat emitted making them very efficient.

They are small and can be turned on and off very quickly making them ideal for TV and display applications. OLED displays are particularly good because they only draw power on the pixels that need lighting unlike a Liquid Crystal Display that requires a backlight.

How only drawing power when needed gives deeper colours

Unlike Plasmas, LCD, rear projection and old CRT displays - a black screen with OLED screen technology requires zero power input. The result of this is a rich 'dark' black giving a very large contrast ratio of 1,000,000:1 between lightest and darkest areas. Viewing an OLED display is far easier on the eye and the colors are much more vivid and natural to look at.

The Real Contrast Ratio

Currently plasma displays' highest ratios are 30,000:1 and typical ANSI contrast ratios for LCDs come in from 100:1 to 5,000:1.

ANSI contrast ratio is measured by displaying 16 black and white squares on a screen at the same time.

The dynamic ratio quoted by some LCD TV makers can be as high as 1,000,000:1 because the back-light found behind an LCD can be dimmed for images on-screen that are darker on average which unfortunately also results in dimming of the brightest parts of the image.

This gives the illusion of a higher contrast ratio.

OLED provides exactly what it says on the box!

A typical OLED display subjected to an ANSI contrast test can achieve a 1,000,000:1 contrast ratio without tricks because no power is supplied to the pixels on the display that are black and not in use.

The Sony XEL-1 OLED TV is the worlds first TV available with this technology with a natural one million to one contrast ratio.

This is the first TV of its' kind to grace the world and is just the beginning of what could be a future dominated by OLED tvs and computer monitors.

OLED - It's a Kind of Plastic

Because the material used is a type of plastic there are many potential uses:

• Flexible displays
• Low power hangable lighting
• Lighting and displays integrated into objects
• Wearable lighting
• A TV on your tummy

An OLED is made up of four layers:

• Cathode (-)
• Emissive
• Conductive
• Anode (+)

Voltage is applied across the OLED device allowing electrons to travel from the cathode through the emissive layer to make positively charged electron holes in the conductive layer where the anode draws those electrons.

Quite simply, the anode is drawing electrons through the emissive layer to provide positive electron holes in the conductive layer. Then the Positive holes and the Electrons collide and recombine which leads to a drop in the electron energy level as visible light radiation is emitted.