Films and Coatings Advance the State of Displays


by Ion Bita

Welcome to 2011, and a Happy New Year to all. We start the year with a look at some of the recent developments in the areas of display films and coating technologies.

In a broad sense, the topic of films and coatings cuts across many of the key building blocks of displays – panel manufacturing, optical enhancement films, components such as touch sensors, and display assembly processes such as lamination and bonding. Many noteworthy developments were reported in all of these areas at the 2010 SID Display Week Symposium, with progress made in materials, processes, device architectures, and applications. One of the most interesting and exciting trends we are seeing is the hybridization of these display technology platforms with non-display applications, such as general lighting and photovoltaics, a result of synergies in large-substrate device manufacturing and light-management solutions. I believe that these synergies will drive the display industry to continue to expand significantly in the coming years, by not only continuing to enrich the visual experience of information displays, but also enabling the growth of other key industries with potential for even larger impact on the typical consumer.

We assembled in this issue a collection of three articles from companies that are leaders in developing display technologies with potential for enabling synergies across multiple industries.

The first contribution is by John Schultz and Bret Haldin from 3M, a company that needs no introduction to the display community, given its long history of achievements in display-enhancement films and materials. Their article, "Market Evolution and Demand for Optical Films," gives a snapshot for developments in the area of display films and touch-sensor technologies. As a highlight, the authors show how the LCD optical-films platform is getting reshaped to enable critical developments in the younger field of 3-D displays that do not require glasses (autostereotopic viewing). A particular type of 3-D enhancement-film solution developed at 3M is described, including a double-sided patterned film with a microlens array on the side of a directional backlight unit and a microprismatic array on the LCD-panel size that is registered to the other surface with micron-level tolerances. An important feature of this innovative solution is that the microlens film does not need precise alignment with the LCD pixels or light-guide features, simplifying module assembly at the OEMs.

The next article is by Jong-Souk Yeo, Tim Koch, et al. from Hewlett-Packard, reporting on impressive progress in flexible-display fabrication and architectures in "Paper-Like Electronic Media: The Case for R2R-Processed Full-Color Reflective Displays." This article showcases a comprehensive approach towards developing a novel reflective display technology – an electrokinetic pixel technology based on electrochromic coatings stacked for full-color operation, development of transparent metal-oxide TFTs, and a roll-to-roll (R2R) processing platform for flexible plastic substrate fabrication based on the self-aligned imprint lithography process developed at HP. This unique combination of a color-display technology in a plastic R2R-fabricated active-matrix backplane is discussed as enabling a scalable platform for low-power transparent print-like media and a path towards eco-friendly bright full-color flexible electronic media that can be extended to new markets such as digital signage.

The third article, "Solution Coating Technology for AMOLED Displays," by Reid Chesterfield et al. from DuPont Displays, presents an overview of perhaps the most advanced implementation of solution-processed electronic material coatings and their use for large-area electronic device fabrication to date. Most solution-based electronic coatings found in large-scale manufacturing are typically used for less-demanding passive devices. The DuPont team presents an overview of a systematic approach for developing solution-based coating methods for ultrathin semiconductor layers and device fabrication on large-area glass substrates, based on engineering the OLED material itself, the printing equipment and process, and the necessary substrate engineering necessary to create a patterned RGB three-color OLED display architecture. As highlights, impressive long-range uniformities of +3% for organic semiconductor layers as thin as 600 Å are shown, and instrumental development of customized metrology and analytical tools to characterize and develop these advanced processes is discussed.

Though the selection of articles was necessarily small, we hope that these snapshots of current developments in display materials, processing, and device architectures will provide glimpses into the exciting future ahead of us, where higher performance displays will emerge, as well as new applications that will result from hybridizing these advanced display technologies with emerging ones.

Last but not least – a happy, healthy, and prosperous new year to all! •


Ion Bita is Staff Engineer/Manager, Display Technology Center, at Qualcomm MEM