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According to an NPD DisplaySearch OLED Technology Report, organic light emitting diodes (OLED) technology advanced rapidly in 2011, a trend that the research firm forecasts will continue through this decade.
OLED technology has progressed in areas including organic materials, color patterning, electronic driving methods, and encapsulation. However, the ability to scale OLED display manufacturing to fabs larger than the current Gen 5.5 has yet to be demonstrated, and the cost of larger panels is not yet clear.
OLED emerged in the 1980s from laboratories at Eastman Kodak in the US and Cambridge University in the UK, and was first commercialized in the late 1990s. Enthusiasm has increased recently as Samsung Mobile Displays has started manufacturing active matrix OLED (AMOLED) displays in a Gen 5.5 fab and announced plans to build a Gen 8 fab (as did LG Display), and several other suppliers entered or re-entered OLED display manufacturing, including AUO, CMI, IRICO, Tianma, and BOE.
OLEDs offer a solid-state solution for displays, lighting, and organic electronics. The OLED displays can provide high contrast ratio, fast response time, wide color gamut, and wide viewing angle, while operating in a broad temperature range at low power consumption. In addition, OLED technology enables thin devices that can be both flexible and transparent.
OLED display revenues are estimated to exceed $4 billion in 2011 (approximately 4% of flat panel display revenues), and are forecast to reach more than $20 billion (approximately 16% of the total display industry by 2018. In addition, OLED lighting gained momentum in 2011, and is forecast to reach revenues of approximately $6 billion by 2018.
"OLED displays operate through direct emission, as opposed to transmissive LCD or reflective displays, which enables area lighting," said Jennifer Colegrove, PhD, Vice President of Emerging Display Technologies for NPD DisplaySearch. "The technology has made good progress and is ready to enter large-size applications, but low cost manufacturing for large sizes is still a challenge."
OLED is now a mass-market technology in small/medium displays, particularly in smart phone applications. Investments in Gen 8 (2200 ? 2500 mm) fabs indicate that AMOLED will compete in larger size applications, such as in TV and mobile PCs, within two years. Samsung released a 7.7" AMOLED tablet PC in December 2011, and more tablet and other mobile PCs are expected in 2012. LG is expected to enter the market in 2012 with a 55" AMOLED TV. With technology improvements, NPD DisplaySearch forecasts AMOLED will enter other applications as well.
While nearly all AMOLEDs on the market are currently based on LTPS, several companies are developing AMOLEDs using oxide or a-Si TFT backplanes, and are likely to start production in 2012.
Comparison of LTPS, a-Si, and Oxide TFT for AMOLED
Characteristic |
LTPS |
a-Si |
Oxide TFT |
Electron
mobility
|
Excellent
10‑500 cm²/VS
|
Poor
0.5 cm²/VS |
Good
1-40 cm²/VS |
Uniformity
|
Poor
|
Excellent
|
Good with amorphous type,
poor with crystalline type
|
Stability |
Excellent |
Poor |
Poor |
Scalable
|
Limited to <40” |
Excellent, >100”
|
Potential to 100”
|
Process temp
|
High
>400°C |
Typical ~300°C,
some low temp process can be ~150°C
|
Typical ~200°C,
but some anneal at 350°C |
Cost
|
High
|
Low
|
Medium
|
Availability |
Yes
MP |
Demo for AMOLED;
Announced by
RiTdisplay and IGNIS;
MP by end of 2011 |
Demo for AMOLED;
MP estimated
by end of 2012 |
Challenges |
Uniformity, cost, scalability |
Poor mobility;
poor stability |
Threshold voltage unstable;
manufacturing process not mature |
Source: NPD DisplaySearch OLED Technology Report |