This article discusses printing technologies for OLEDs and examines the ways in which OLEDs are transforming the way we define structure and light.
By Barry Young
Organic light-emitting diodes (OLEDs) are a new entry in the display and lighting markets, and while production is currently limited to some form of vacuum thermal evaporation (VTE), there are several programs working on placing chemicals into solution for printing.
Printing OLEDs appears to solve many of the problems inherent in the evaporation process, including high material utilization in the range of 75-85% vs. 3-20% for evaporation; fine patterning, which is limited to 15µm for evaporation; less expensive than vacuum deposition; compatible with roll-to-roll manufacturing and very thin substrates (<100 µm); expanded at very low capital costs by increasing width of the substrate or by speeding up the roll; conductive polymers used to print organic TFTs; operation at atmosphere and at low temperatures; enables the use of plastic, creating new form factors.
Printing is faster, more efficient, scalable, and lower cost than VTE. The opportunity for printing OLEDs is substantial because OLED technology used in lighting and displays is today a $4 billion market and is expected to grow to more than $25 billion by 2017, as depicted in Figure 1.
The CAGR for OLED revenue between 2011 and 2017 is forecasted to be 37%. This growth is being driven by the performance improvements that OLEDs have in the display and lighting industries, as summarized in Table 1.
Moreover, the future is even more promising as the technology matures and OLEDs reach new levels of performance driven by the advances in organic material, new stack designs, and the maturation of the manufacturing process:
- Lifetimes (L70) in the range of 100,000 hours at 1000 cd/m2 and 50,000 hours at 3000 cd/m2
- A doubling of luminous efficiency using new light extraction methods
- Flexible substrates with transparency at >50%
- Low-cost manufacturing
These gains in market acceptability and the accompanying growth projections are backed by a number of real world activities:
Samsung (SMD) produced more than 30 million smartphone OLED displays in Q3 2011, up almost 100% Q/Q. Samsung and LG Display report availability of 55-in. AMOLED TVs in 2012, built on Gen 8.5 Fabs (2200 x 2520 mm). Sumitomo to open facility to make polymer material, hinting at a customer that will make 40-in. TVs on plastic. Japan Display buys sixth Gen Fab from Panasonic—will convert it from a-Si to p-Si and manufacture AMOLED displays.
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