How to reduce large-size AMOLED display fab costs

August 9, 2012 — Active-matrix organic light-emitting diode (AMOLED) displays are growing rapidly and offer many performance benefits over liquid crystal displays (LCDs). However, 55” AMOLED TV displays cost 8-10x as much as a comparable LCD to manufacture.

Also read: AMOLED manufacturing improvements to enable TV market share grab

According to the NPD DisplaySearch AMOLED Process Roadmap Report, the manufacturing cost of a 55” oxide TFT-based AMOLED using white OLED (WOLED) with color filters is 8x that of a high-end TFT LCD display of equal size. The cost multiplier of a 55” AMOLED module using red, green, and blue (RGB) OLED is 10x. These higher costs are mainly a result of low yields and high materials costs.

LCD manufacturing is a mature process with slower, more incremental cost reduction. AMOLED cost reduction efforts are in their infancy, said Jae-Hak Choi, senior analyst, FPD Manufacturing for NPD DisplaySearch. These could include new and improved processes, printing technology, and higher-performance materials that will take AMOLED prices to parity with LCD in the long term.

Figure. Relative manufacturing costs of technologies for 55” TV panels. Based on current yield and material cost assumptions. Source: NPD DisplaySearch AMOLED Process Roadmap Report.

In order to scale up to large sizes, advancements in several aspects of AMOLED manufacturing are needed, including the active matrix backplane, organic material deposition, and encapsulation. Because oxide thin-film transistors (OTFT) require lower capital costs and are similar to existing amorphous silicon TFT (a-Si TFT), the technology offers a strong alternative to the low-temperature polysilicon (LTPS) TFT currently used for AMOLED. However, there are many hurdles for mass production of oxide TFT, particularly threshold voltage shifts, which are continuing to prove problematic for AMOLED production.

While indium gallium zinc oxide (IGZO) and other forms of oxide TFT show great promise for backplanes, progress in scaling up LTPS production is also being made by increasing the excimer laser beam width to 1300 mm. In addition, the current method of depositing red, green, and blue materials by evaporation through a fine metal mask is being continuously improved. Pixel densities of 250 ppi are now possible, and over 280 ppi is feasible.

“High resolution patterning such as laser induced thermal imaging (LITI) and material improvements are still required for AMOLED to be highly competitive for super-high-resolution flat panel displays,” Choi said.

Manufacturing processes for small, 4” AMOLED displays are more mature, creating a much smaller cost premium over LCDs (<1.3x). Most AMOLED capacity is currently dedicated to small/medium production for smart phones, but much of the future capacity increase will be driven by fabs dedicated to TV production. Uncertainties abound, as AMOLED technology has not yet been proven in large-size TVs.

Based on planned investments, NPD DisplaySearch forecasts that the AMOLED market will grow nearly tenfold from 2.3M square meters in 2012 to more than 22M in 2016.

Samsung Display has been highly successful in its small/medium AMOLED production because it has been able to raise yields to near-LCD levels. This implies that manufacturers can potentially lower large-size AMOLED TV costs to be competitive with LCD TVs in the future.

The NPD DisplaySearch AMOLED Process Roadmap Report provides in-depth data and analysis on OLED manufacturing technologies including materials, backplanes, OLED, and encapsulation. It also includes an analysis of benefits, opportunities, negatives, and challenges for each technology. Unique to the industry, the report shows specification roadmaps for OLED manufacturing through 2016 and indicates which manufacturing technologies will be required to achieve stability and performance. Also, the report provides a unique equipment investment simulation and module cost modeling analysis. NPD DisplaySearch provides market research and consulting, specializing in the display supply chain, as well as the emerging photovoltaic/solar cell industries. For more information on DisplaySearch analysts, reports and industry events, visit http://www.displaysearch.com/.

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