Like LCD, organic light emitting diodes can also be divided into active and passive types. Passive organic light-emitting diodes (OLEDs) first appeared, which used row and column scanning to drive the corresponding pixels to emit light to form a screen display, so the cost was low and the process was relatively simple. However, due to the refresh rate and other problems, they were only used for small-size display screens. Active display technology is similar to current TFT LCD. Organic light-emitting diode (OLED) luminescent materials are integrated on silicon wafer, and each pixel is driven by a transistor. So that the refresh rate increases rapidly.
Motorola is the first mobile phone manufacturer to use organic light-emitting diode technology as the display screen. At the end of 2000, Motorola began to use organic light-emitting diodes as display materials for mobile phones. But so far, Moto's organic light-emitting diode display has not appeared in China, and it may only be sold in China. Since then, many mobile phone manufacturers have invested in the research and development of organic light-emitting diode displays. For example, the external screen of LG's G7030 on the market now is a passive organic light-emitting diode display.
Compared with the best TFT-LCD, organic light-emitting diodes have the following advantages:
1, the thickness of the core layer of the organic light-emitting diode device is very thin, the thickness can be less than 1 mm, and the thickness is1/3 of that of the liquid crystal;
2. The organic light-emitting diode device is an all-solid-state mechanism, which has no vacuum and liquid substances, good impact resistance and can adapt to harsh environments such as huge acceleration and vibration;
3. The characteristics of active luminescence make the organic light-emitting diode almost free from viewing angle problems. The brightness of the organic light-emitting diode is 100000cd/ m2, while the TFT brightness of the best notebook at present is 350-400cd. Therefore, when viewing the OLED from a large angle, the displayed image will not be distorted.
4. The response speed of a single pixel of the organic light-emitting diode device is 1000 times that of the liquid crystal device, which can realize wonderful video playback;
5. Good low-temperature characteristics, normal display at minus 40 degrees, but poor LCD display effect at low temperature;
6. The requirements for materials and processes are about 1/3 lower than those of LCD, and the cost will be lower;
7. The luminous conversion efficiency is high, and it does not need to be in a light source, so the energy consumption is lower than that of liquid crystal;
8. Organic light-emitting diodes can be made on substrates of different materials and can be made into flexible displays.
As an excellent display technology, organic light-emitting diode display screen has the characteristics of high visibility and brightness, fast response, light weight, thin thickness and simple structure. Therefore, in addition to challenging the traditional CRT and LCD in the traditional digital application field, it can also open up new markets with its unique performance of flexible design, such as electronic paper, folding TV, notebook computers and so on. However, at this stage, it will take some time for OLED to completely replace LCD, and TFT-LCD technology has not stagnated. LCD panel manufacturers have also made great efforts to improve the viewing angle, brightness, contrast and response speed of their products. Therefore, when the two are fighting in the mainstream market, their strength is equal.