OLED (organic light-emitting diode) is emissive device. It means they fashion their own light, just the opposite to liquid crystal displays that need a separate light source. Consequently, OLED devices use lesser power and can be competent of higher brightness and better color than liquid crystal micro displays. OLED technology is based on carbon based organic materials that produce light when electricity runs through them. As OLEDs do not need a filter to modify colors different LCD displays, they are simpler to make, more competent and much thinner. OLEDs have a wonderful picture quality, brilliant colors, quick response rate and a broad viewing angle. If you are curious to know how OLED technology works, scroll down.

OLED Materials

OLED is like led a semi-conductor. Its thickness is about 100-500 nm or about 200 times thinner than a human hear. OLED screen is made of several components:

1 Transparent anode that removes electrons on electric current flows
2 Organic layers of organic molecules/polymers
3 Conductive layer made artificial organic molecules.
4 Emissive layer is made of other organic molecules transporting electrons out of the cathode. Light is made in this layer.
5 The cathode injects electrons with an electric current flow.

How OLED Technology Functions?

The five major parts of OLED: anode, cathode, substrate, and two organic layers. The anode removes electrons, the cathode injects electrons. The substrate supports the OLED. The organic layers are an emissive layer and a conducting layer. When molecules transport electrons from the cathode, light is emitted.
The light emitting process is known as electrophosphorescence. It is just like the process of the conventional LEDs. Through the organic layers current keeps flowing from the cathode to the anode. By this, electrons are detached from the conducting layer and are transported to the emissive layer. Holes are left back to the conductive layer at the time of removing process. The holes are shooting over to the emissive layer and combine again with the electrons. When the electrons jump down into the holes they release additional energy as light.

Types of OLEDs

There are various types of OLEDs. The most common are –

Active-matrix OLED- Active-matrix OLEDs are called AMOLED. They use less power than passive-matrix OLEDs. They are well matched for portable devices power-driven by battery. An active-matrix holds pixels that have been incorporated onto a slender film transistor array (called TFT) to shape a matrix. The thin-film transistor performs as a collection of switches to manage the amount of electrical current flowing through each pixel of the OLED.

Passive-matrix OLED- Passive-matrix OLEDs are called PMOLED. They are matched for little display devices as they use more power than active-matrix OLEDs. But the power utilization is still lower than those of traditional LCDs. A passive matrix houses rows and columns formed to a two-dimensional arrangement. A component of this array is called a pixel. Electrical current is applied to the slight film of organic material and then light is emitted. The luster of each pixel demands on the quantity of current applied.

The above account throws bright light on how OLED technology works. You can now, explain others about this technology and get appreciated.

The U.S. Air Force Research Laboratory sponsors Universal Display Corporation display technologies innovator $99,978 for designing the Flexible OLED Display Prototype destined for future military and commercial applications.

A FOLED display will be thinner and lighter weight, more durable, safer, impact resistant, flexible and cost-effective.



The first prototype will demonstrate the capability of rolling around a cylinder and the next design will be of a 6-inch 480 x 480 full-color, active matrix PHOLED display prototype built on metallic foil, flexible enough to wrap around a 2.5 inch diameter cylinder containing the power supplies and wireless communication electronics.



"We are excited to continue the research and development of flexible and rollable OLED technology - an idea that is moving quickly from being a vision to becoming a reality," said Steven V. Abramson, President and Chief Executive Officer of Universal Display. "The U.S. Air Force as well as other branches of the U.S. Department of Defense have been strong supporters of our flexible OLED technology. Also offering thinness, light weight and ruggedness, rollable displays may revolutionize the way soldiers view information on the battlefield and in the cockpit. This program should also support our efforts to commercialize FOLED technology for a variety of novel consumer applications."

The TV model I am telling you about today is Sony’s OLED TV, model number XEL-1, an impressively thin TV of just 3 mm that is available only via the company’s retail stores at a relatively-high price of $2,499 which explains the fact that it’s using one of the latest and advanced display technologies but, though, it measures only 11 inches in diagonal.



The Organic Light Emitting Diode technology allows for a faster response time, wider viewing angles, almost perfect color reproduction, high contrast ratio and outstanding brightness, permitting designers to create extremely thin and light TV panels.
From the two types of OLED, small molecule and polymer, Sony has chosen to use the small type to increase the monitor’s life, and it developed the Organic Thin Film Transistor that can be easily deposited on a flexible plastic display to deliver the world’s first full-color display capable of projecting full-color moving images even when the display is bent.



The OLED’s high contrast is accomplished by turning off pixels when reproducing black and in our case we have an impressive 1,000,000:1 ratio, and yes, I wrote correct.
To sustain it, I will tell you that the technology that contributes to the exceptional color fidelity is Sony’s Super Top Emission meant to achieve 105% of the NTSC color space, with the help of a special micro-cavity and color filters.



Sony OLED TV has a viewing angle of 178 degrees both on horizontal and vertical, 16:9 wide aspect ratio, 960 x 540 pixel native resolution, and the following key elements: comb filter, light sensor, noise reduction, picture adjustment settings, two 2W speakers built-in, S-Force Surround, digital amplifier, sound booster, Dolby Digital AC3, MTC stereo decoder, Memory Stick PRO media slot, and HDMI connectivity.

One of the main drawbacks of the OLED technology is the pretty short life of the display panels manufactured using it, since about 30,000 hours declared for a brand new OLED TV from Sony, the XEL-1 isn't too much at all, considering that most common LCD panels exceed 50,000 hours. Well, that seems to have become a part of the past now, because Toshiba and Panasonic just doubled the life expectancy of OLED displays!

The idea behind the new generation of OLED displays is to increase the efficiency of the way the emitted light is used, so the organic materials used to build the screen have a much longer life expectancy. How is that achieved?

Well, the new OLED displays from Toshiba Matsushita Display Technology added a metal membrane inside the screen, so light from polymers in the substrate is delivered with an increased efficiency, compared to existing models. This way, you can get the same picture quality, with only half the effective brightness delivered by the polymers, so the life of the organic components should double, obviously.

While this sounds great, for now we only know about a prototype display using this technology, so we need to see if products using it start appearing soon enough to push back the LCD TVs a bit, since they are getting better and better with each day...

Taiwan's Chi Mei EL Corportation, or shortly CMEL, is a producer that already offers a few AMOLED panels, and they just announced a new such panel that's likely to be produced in the near future. At this time, CMEL offers 2.2-inch and 2.8-inch panels, and a 4.3-inch model is already announced to start shipping in the second quarter of the year, according to company's president, Peter Chen.

In the image above, you can see the 2.8-inch AMOLED display from CMEL, used in a digital photo frame manufactured by the Chinese company Digital Foci. Since between the existing 2.8-inch display and the 4.3-inch one that has been announced there's quite a gap, CMEL needs to close this gap and, as Chen himself said, the product to do this is going to be a 3.5-inch display, probably, since this screen size became so popular with devices like the iPhone.

Since I mentioned the iPhone, it seems that, according to some sources, Apple may use AMOLED panels for the next-gen iPhone. Hopefully, the life span of such displays will be extended until that happens, because I wouldn't like to have an expensive mobile with a display that may "die" on me after about 5,000 hours...