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14 SMT Magazine • August 2014 Advantages of the technology include the fact that lead time is short—four weeks is typi- cal—and lifetime is good enough for packaging applications. In volume, costs can be less than $10 for relatively large (A4 size) promotional posters, including power supply and display driver. On the downside, voltage supply is high (e.g., 120-240V) and tends to emit a hum, It's also difficult to see the active parts of the dis- play in high levels of light, although that's not an issue for darker environments. Electrochromic Electrochromic (EC) displays are very sim- ple, screen printed structures, characterized by low power consumption. They are low-cost reflective displays that have been used in pro- motional material such as M&S gift cards and the CANVAS magazine cover. Beyond those, it's only been mostly prototypes so far, such as dis- plays for smart cards, gift cards, etc. Ynvisible tends to be the most creative company spearheading the technology so far, with BASF active on the material side (working with Ynvisible on better colour rendition) and ACREO of Sweden also having done significant development work on the topic. In volume, costs would be less than $.05 per active square centimeter. What is problematic and the main reason why there have been sev- eral smaller company failures (e.g., Aveso, Ntera, Ajjer) on this segment is the fact that end users do not like the limited colour range (mostly just blue) and slow response time. Electrophoretic Electrophoretic displays (EPDs) have pro- liferated in e-readers such as the Amazon Kindle, but this market is currently in decline. Consumer goods and healthcare applica- tions have seen e-paper displays as one-offs in magazines (Esquire in 2008), POS posters, and in products such as key fobs, memory sticks, locks, etc. These have been fairly niche ap- plications so far, but technology developers are looking to push further adoption in these markets due to the slowdown in the e-reader space. It's important to point out adopters in this market sector demand good colour ren- dition, a challenge that EPD developers have struggled with. OLED Organic light-emitting diode (OLED) dis- plays are currently mostly made by vacuum processes. Printing is possible and extensively researched but not in commercial products yet. The materials are light emitting materials char- acterized by low power consumption, excellent colour range but still very expensive. Other than their use in smart phones and televisions (OLEDs are already a $10 billion market in 2013 for cell phone displays, OLED TVs were launched in 2013), in the CPG space there have been very limited demonstrations such as those by Toppan Forms (an OLED pow- ered wirelessly) and DNP. PRINtED ELECtRONICs tEChNOLOgy CasE stuDy continues FEaTuRE Figure 2: one example of an electrochromic display.