In the past 2001 for the IT industry, it is a non-calm year, and the same monitor market has also experienced a revolution with a sky. After a few wind and rain, the flat-flat CRT display finally replaced the traditional CRT display in the market, became the mainstream product in the market. But because of the many manufacturers, plus price transparency increase, many manufacturers have moved the LCD market. Because the LCD itself has low radiation, saving space, etc.,, in addition, many manufacturers have propaganda. Make the global LCD shipments aggregate, and the concept of liquid crystal environmental protection is also deeply rooted. However, because of price and other factors, LCD is now fully occupying the mainstream market, but it is the main army of the future monitor market, it seems that the liquid crystal era is true. It also brings a lot of problems while developing, although LCD has the advantages of health, environmental protection, low radiation low energy consumption. However, the LCD response time is slow, the viewing angle is small, the color brightness is low, which limits a large part of the user who has a professional use to use the LCD. And there are many bottlenecks in other places, such as mobile phone display screens, portable discs, etc. So the new generation of OLED technology is born, how is OLEDs being discovered?
The appearance of OLED
Ching w tang, born in Hong Kong, China, graduated from the Department of Chemistry, Taiwan University, Ph.D. In 1975, Joint Kodak, engaged in research in Rochester laboratory, OLED research launched this person, now Wang Mr. Wang is still one of the highest authority in the field. It turned out that in 1987, Mr. Wang Genxiang, who was born in Kodak, was inadvertently found in Kodak. The organic battery can produce glowing phenomena, and then launched a study on OLED. Later, it was found that small molecular organic materials were similar to metal semiconductors, and they can be emitted under electric field, and its electro-optical conversion efficiency is extremely high. Under circuit control, OLED can light up quickly and extinguish, 60 times per second, high brightness, and work voltage is very. Low. Also also in 1987, the doctoral Jeremy Burroughes of the University of Cambridge, the University of Cambridge, proves that macromolecular polymers also have field effects. After that, Burroughes founded the Cambridge display technology company with his mentor, and the road of OLD is also got.
OLED structure
With regard to the structure of the OLED, we can make a metaphor. In fact, each OLED unit is like a hamburger, the luminescent material is sandwiched in the middle of the vegetables. Each OLED's display unit can be controlled by three different colors of different colors, which are shown in the figure. OLEDs are the same as LCD, and there are active and passive points. The passive mode is illuminated by the unit selected by the ranks address. In the active mode, there is a thin film transistor (TFT) after the OLED unit, and the light emitting unit is lit in the TFT drive. The active OLED is saplified, but the passive OLED display performance is better.
Most of the OLED samples we have seen in the current market are monochrome or multi-colored, but the diversity of materials and processes allows OLEDs to have a variety of ways to achieve color display. There are mainly less than six clocks: 1, different materials are made of red, green, blue three colors, like CRT display, splicing into a color pixel by three-color pixels; 2, using white light, like LCD display, through three The color filter forming color pixels; 3, a special material can be displayed in different driving voltages; 4, using a blue light, excitation fluorescent substances emit a variety of color light; 5, laser resonance mode ; 6, overlapping red, green, blue, blue, and blue, constitute color pixels
Comparison of OLED and LCD
We list several OLEDs and advantages, you can see the advantages of OLEDs very clearly. 1. The core layer thickness of the OLED device is very thin, the thickness can be less than 1 mm, the thickness is 1/3 of the liquid crystal; 2. OLED device is a full solid state mechanism, no vacuum, liquid material, good shock resistance, can accommodate huge acceleration, Vibration and other harsh environments; 3. The active illumination characteristics make OLEDs that have little angle problems, watch in a large angle, showing the picture does not matter; 4. The response speed of a single pixel of the OLED device is 1000 times the liquid crystal element, which Video playback; 5. Low temperature characteristics, can be normal to 40 degrees, while the liquid crystal is not shown in low temperature; 6. The requirements for materials and processes are reduced by about 1/3, which will be lower. ; 7. Luminous conversion efficiency is high, energy consumption is slightly lower; 8. A single pixel size of the OLED device can be quite small, and there is also a large "weight loss" potential, which is very suitable for use in micro-display devices; 9. OLED Can be manufactured on different material substrates, which can be made in a soft display that can be more than how to compare Olde and LCD, it will find that OLD has a lot of advantages. OLED can be emitted by itself, and the LCD does not illuminate. So the OLED is much larger than the LCD, the contrast is large, the color effect is also. OLEDs do not have limitations of the perspective range, and the viewing angle can generally reach 160 °, which will not distract from the side. The LCD needs to be light on the background, and the OLED only needs to light up the unit to power up, and the voltage is low, so it is more power saving. The weight of the OLED is much more lighter than the LCD. The material required for OLED is very small, the manufacturing process is simple, only 86 steps, and LCD has 200. It is estimated that the cost of the OLED mass production is more than 20% more than the LCD, which is why OLED technology replaces existing LCD technology because cost and performance is determined. The most important disadvantage of OLED is that the life is shorter than the LCD, and can only reach 5,000 hours, while LCD can reach 10,000 hours. It is said to eliminate this gap and at least 4 to 5 years. This makes the current OLED more suitable for unusually used devices, such as car DVD players, handheld PDAs, digital cameras, digital cameras, and portable discs, but not suitable as a display output device as a computer.
The future development of OLED
At present, more than 90 manufacturers have been engaged in OLED, they are divided into two major groups of small molecule OLEDs and polymer OLEDs. The small molecule OLED is representative of Kodak, as well as Sony, Sanyo, TDK, Emagin, Pioneer, NEC, Samsung and other companies; polymer OLEDs have Philips, Epson, Dupont, Toshiba and other companies. In addition, China Taiwan Province also has companies to develop production OLEDs. There are already some big companies, launched a display model. Sony's resolution is 800 × 600 33cm OLED display, which is planned to be produced in 2003. Emagin has developed an OLED display with a resolution of 640 × 480, a size of 2.2cm × 1.65cm, which has been used on Linux watches with wireless Internet feature in IBM. According to an investigation of an authoritative institution, the global OLD market turnover is $ 18 million. The 2001 will be $ 84 million, and will reach $ 45 billion in 2005. After 2005, it has become the mainstream of the monitor market. Will be the situation in the world of OLED.
