Large flat screens have long ceased to be fiction. The future was even stranger and more interesting than it is portrayed in science fiction films 80-90-ies.
Anyway, nobody expected that incredible gadgets appear so soon. And, if LCD and plasma technology came on the market for quite some time, the OLED has become a “dark horse”, suddenly pull ahead – before, probably lacked daring minds, capable to turn the LED “(Light Emitting Diode or LED) in large displays with an incredible image quality. Now, a miracle occurred. And no Harry Potter here is not to blame. Over the future working ordinary workers of mega-corporations like Sony, Toshiba, Panasonic, etc.
In essence LED – semiconductors, luminescent in different colors under the influence of elektrichesvta. The first versions of LED-diodes have been inorganic. They are very reliable and does not “burn out”, but consuming too much energy and have very high costs. Variants of this type were used Sony to create large displays in 70 years – then the company made happy with large flat screens visitors stadiums, classrooms and concert halls.
However, only use instead of conventional conductors of organic polymers allowed to say that the LED-technology was held as a commercial product.
Technology
OLED (the same LED-LED only uses organic ingredients) – Semiconductor 100 – 500 nm thick (about 200 times thinner than a human hair). OLED-panel may consist of two or three layers of organic polymer. The most common two-layer system.
A typical OLED-display consists of the following elements:
- Substrate – plastic, glass, etc. The basis of the display, which are applied / installed all the other design elements. – Anode (transparent) – under the influence of an electric current adds to the organic layer is so called. “hole” (atoms with missing electrons).
- Cathode. Depending on the type of OLED can be transparent or opaque. Once through the electric current is passed, a source of electrons.
The organic layers:
- Conductive Layer. Consists of organic molecules, plastics), “lift” holes from the anode.
- emitter (emitting layer). Also consists of plastic, but another type. Responsible for the “transport” of electrons from the cathode.
Why OLED lights?
1. The current source is connected to the cathode (+) and anode (-) OLED-display.
2. The stream of electrons moving from cathode to anode through the organic layers. Adds electrons to the cathode of the organic layer emitter. Anode “delivers” electrons from the conductive layer of organic molecules.
3. At the boundary between the emitter and the conductive layer, electrons are “holes” (atoms with missing electrons on energy levels). When an electron is a hole, it populates the energy level. As a result, releasing a photon (light).
4. OLED panel begins to glow.
5. Light color depends on the type of organic molecules in the conducting layer. For the production of displays are commonly used conductive layer, consisting of several types of organic films.
6. Brightness depends on the voltage.
Types of OLED:
Passive-matrix OLED (OLED with passive matrix);
Active-matrix OLED (OLED Active Matrix);
Transparent OLED (transparent OLED);
Top-emitting OLED (OLED with an opaque substrate);
Foldable OLED (flexible OLED);
White OLED (white OLED).
Passive-matrix OLED
OLED with passive matrix consists of numerous strips, cathode, organic layers and the strip-anode. The crossing of cathodes and anodes – light emitting pixels. Depending on which pixel to “insert”, on one or another pair of cathode / anode voltage is applied.
PMOLED is simple to manufacture, but it consumes more energy than other types of OLED. It is best suited for this option displays a small size (2-3 “) – in cell phones, PDAs, and MP3-players. However, even PMOLED consume less energy than a comparable size LCD.
Active-matrix OLED (AMOLED)
OLED Active Matrix uses only one pair of cathode / anode (in this case did not apply the strip, and this panel). In addition, the anode has a substrate of thin-film TFT-transistors, which “points” to which a layer of electric current is applied.
AMOLED consumes less energy and, therefore, can be used in displays of larger size. In the case of video – with active matrix displays have better response time. AMOLED can be used in monitors, TVs, and advertising billboards.
Transparent OLED
Transparent OLED, in full accordance with the title, consists only of transparent components. When the current is not supplied to him, the display is virtually transparent. Included display emits light in both directions. Using this technology, you can create a transparent “glass” windows “in which data is displayed directly on the surface. As an example – in the military and civil aviation of sophisticated vehicles, etc. For transparent OLED is suitable both active and passive matrix.
Top-emitting OLED
Displays of this type are opaque or even mirror substrate-based. Optimal option for them – an active matrix. Manufacturers can use the displays, for example, in some modern smart cards.
Foldable OLED
Dislpei new generation. As a substrate used strips of highly flexible foil or plastic. Because of this, the displays are very lightweight and easy to change the shape. The use of mobile phones and PDAs can eliminate failure display (eg, falling), in theory, flexible displays can be integrated with the fabric, creating a “smart” clothes with OLED-elements.
White OLED
White OLED-panel emit light more bright, comfortable on the eyes than fluorescent lights. Moreover, such items do not have matrix – either active or passive, since the need for a pixel no. With the addition of filters, you can create a lamp of any color. At the same time, OLED-lamps are very economical. Because OLED-elements can be made larger, in the long term they can be replaced in homes and offices of other lamp types.
Advantages and disadvantages of technology:
Advantages of OLED:
* OLED is much lighter and thinner than LCD or inorganic LED. At the same time, they are more flexible. For example, to create the same clothes with integrated LCD is unlikely in the foreseeable future.
* OLED is brighter than LCD or LED. Since the OLED layers are much thinner than the crystalline layers LED, you can create a truly multi-layered “sandwich” with high luminosity.
* Since the OLED does not need a backlight like LCD, it consumes much less energy. This is especially important for devices that feed on batteries / accumulators.
* OLED is relatively easy to manufacture – Plastic fibers can easily make a larger display. Similar dimensions of the LCD matrix is difficult to establish.
* Since the OLED, unlike LCD, is itself the source of light, it has wide viewing angles (170 degrees or more).
Disadvantages of OLED:
* Resource. Although red and green OLED-layers is sufficient for 46000-230000 hours, the blue layer is now able to operate effectively only about 14,000 hours.
* Manufacturing. Release OLED while costing quite expensive, much more expensive than LCD.
* Water / moisture. Easily disrupts the OLED-display. However, it is important for all existing technologies.
However, progress has not stopped. In the development of OLED-industry invested huge amounts of money involved the best minds of humanity, for the scientific work highlighted the incredible production and research facilities. Shortcomings, no doubt, will soon be eliminated.
Mobile phones, iPods and PDAs with OLED-displays – are already commonplace. On sale are the first TV based on OLED, yet not too big, but too expensive. But the widespread adoption of technology, it’s only a matter of time.
