During the late 2007 Acreo launched its low cost paper display technology under the PaperDisplay trade name (www.PaperDisplay.se ). PaperDisplay manufactures and sells low cost information displays printed on paper substrates for applications such as smart labels, smart packaging, printed matters, etc.
The PaperDisplay products are based on Acreo’s patented electro-chromic (EC) paper electronics technology. The display element is a lateral electro-chromic cell consisting of patterned transparent electrochromic PEDOT/PSS electrodes covered with a solid electrolyte as illustrated in the figure. The paper display is partly bi-stable which means that once it is switched it takes only a small current to keep it updated. The basic structure is based on paper (or plastic) substrates coated or printed with a layer of PEDOT/PSS formulation to define the working electrodes. The electrodes are overprinted with a UV-curable electrolyte system, allowing for a fast curing process, before an encapsulation is laminated on top of the display unit for mechanical protection.
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A sketch of the lateral display configuration
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PaperDisplay is selling evaluation kits and customer specific prototypes as well as volume series. Licensing can also be considered. A slightly modified label printing press is used to manufacture the paper displays in only three process steps. Optional printing steps can be used for graphic appearances. The printing speed is 5 to 20 m/min but it has a potential to be increased to more than 100 m/min.
Evaluation Kit
For an easy evaluation of the technology, PaperDisplay offers an evaluation kit consisting of paper display samples that have been designed to give some application examples, but can also be used for more extensive evaluation purposes.
To facilitate easy testing there is a 3 V power source with a three-way switch supplied. The activation of the organic paper display is simply done by connecting the power source to the connection sites on the display as shown in the figures. The display can be turned “on”, “off” and even inverted by pushing the switch in either direction. Dependent on polarity the display will turn from transparent to dark blue when switched. The display is semi bi-stable, i.e. it stays dark blue for a period of time without any power applied.
The electrode attached to the positive polarity will be further oxidized and stay in its relatively transparent state, see the sketch above, while the electrode attached to the negative polarity will be reduced and colored.
For more information concerning other PaperDisplay products consult the PaperDisplay web page www.PaperDisplay.se.