CircuiTree - July 2008 - (Page 37)

[ BPA Growth Curves ] Table 3 OLED Technology Progression 2007 Small and Medium Passive matrix Inorganic backplane Small molecule Glass substrate Source: BPA 2010+ Small and Medium Active matrix Organic backplane Polymer Polymer Table 4 Smart Label Technology Progress 2007 Printing Process Format Substrates Source: BPA Inkjet Discrete component PET (Class 2) Modified paper 2012 and Beyond Inkjet/gravure, etc. Integrated into the package label Paper Range of plastics assist this technology in its penetration into power-sensitive applications such as those required in portable displays. As such there are opportunities for materials companies to produce emissive materials that require lower driver voltages while still improving the levels of brightness. This, in general terms, is a tradeoff in the properties as increased emissivity at a higher voltage reduces the lifetime of the display. Other technology needs and required developments for OLED are shown in Table 3. Organic backplanes will be a key cost enabler for plastic electronics displays. Developments would indicate this is technically feasible. The future challenge is to scale up manufacture. OLED lighting is a potential major plastic electronics opportunity; however, commercial quantities due to current material price and stability will not result in a major market expansion before 2012. Organic semiconductors for sensors is a key plastic electronics market, particularly lab on chip, where a number of functions can be integrated in one product. The technology does not need an additional reader, making it cost competitive with silicon-based products. For voltaic cells, the tradeoff is between cost and efﬁciency. Currently organic and therefore printable systems have a commercial efﬁciency of less than 5 percent. This compares to silicon’s 15 to 20 percent. It will be at least 10 years before the technology catches up, so the organic or hybrid systems will be used only where ﬂexibility is a high priority and charge demand bud- gets are low. Smart active labels, on the other hand, are next-generation products, representing the convergence of two parallel technologies: smart labels and active tags. An active device contains a battery, which provides the tag with a different range of performance options but consequently makes the tags relatively expensive and bulky. Robustness and reusability are therefore important issues for active tags. Table 4 summarizes this trend. The printing process is referred to as the technology used to deposit any materials during the manufacture of the label. One of the three major challenges for the plastic electronics industry is low-cost, preferably R2R printing. Printing equipment has been developed to print either characters or images on a packet, newspaper, or magazine. This start point has limitations when there is a need not only to print highly ﬁlled materials but also ﬁner features than that currently demanded by the general printing industry. A good example of this is that the human eye can only pick up an error in dot placement greater than 20 µm. In addition, the human eye recognizes wrong color when there is a dot placement error of 50 µm or more. Such levels of dot error placement in a display results in a blank line that is clearly visible. So, in practice, high-volume printing machines with resolutions well below these ﬁgures will be needed. As the performance of the semiconductor materials continue to improve, the dimensional requirements of the printed structures could be relaxed without sacriﬁcing electrical functionality. Hopefully it can be seen that plastic electronics is a key enabling technology for a range of new applications (i.e., rollable displays for E-readers). It is agreed that the potential in this market is huge. How big and when are open to debate, especially as there are few high-volume applications to date. ■ Mark Hutton is managing director and senior consultant, BPA Consulting Ltd. His areas of expertise include IC packaging, advanced substrates, assembly materials, and processes. Email: m.hutton@bpaconsulting.com Figure 3 Total Plastic Electronics World Value ($ Millions) circuitree.com • July 2008 37 http://circuitree.com

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CircuiTree - July 2008 Contents My Line Industry Review Tech Talk Flexible Thinking Toward a PCB Production Floor Metric for Go/No Go Testing of Lossy High-Speed Transmission Lines Intelligent Design 20-Year Retrospective Ask the Flexperts Environmentally Speaking BPA Growth Curves Considering Design Variants to Maximize Process Efficiency Market Outlook Technical Product Spotlights Classified Ads Upcoming Events Ad Index

CircuiTree - July 2008

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