Electronic paper (E-Paper) is a technology where “ink dots” (pixels) are electronically controlled thus producing either a black dot or not. This technology can be most readily seen in e-book readers such as those produced by Kindle. What
E-Paper aims to do, is reproduce the same properties that are found with ordinary printed material, such as a newspaper, but with the added flexibility of being able to change what you are seeing electronically. One of the key properties of E-Paper is that of being bi-stable. Bi-stable means that what has been electronically imaged on the E-Paper will remain as a permanent image even with all power completely removed. Also, like printed newspaper, E-Paper can be easily read in both ordinary ambient light or in very high ambient light conditions. To change the image or text shown on an E-Paper display requires only the very tiniest amount of energy to effect that change, then, the power can be removed leaving clear, crisp images or characters.
The other major benefit of an E-Paper display module is that of heat dissipation. As the amount of energy required to change the display is so small, and then, after that, no energy at all, issues surrounding heat buildup in a display is significantly reduced. Many LED signs that are used over roadways produce a great deal of heat. With high ambient air temperatures as can be found in hot countries (like Australia), power supplies and LED modules are much more likely to fail. This can often be observed with mobile, trailer mounted LED displays where parts of the message are not being displayed correctly. This is normally due to LED failures or other electronics in LED signs being subjected to high temperatures.
Another contributing factor to LED module failures is that in high ambient light conditions, they have to be driven harder to produce maximum brightness. This is required so that the effects of (for example the sun shining on them) attempts to avoid ‘washing out’ if they are on or off. This phenomenon is most often seen when you are approaching a set of traffic lights and the sun is either setting or rising directly behind you. You then find it difficult to tell which of the three colours of the traffic lights are actually on or off. This is called a ‘phantom image’. Driving LED’s harder also produces, once again, greater heat buildup. EPD modules do not suffer from this affect, quite the opposite. The greater the light falling on the module, the higher the contrast ratio appears and thus, just like a sheet of printed paper, very much easier to read.
Just as can be seen with a Kindle, for very low or no light conditions, NGS has developed some unique solutions using front or side low energy illumination combined with special front panel screens. This then allows EPD modules that have no external light source to be illuminated.
LSID (part owner of NGS) commenced researching and then developing E-Paper modules in 2008. The aim was to produce panels that could be simply added together to form ever larger displays. Think of it as many kindles placed on a large wall and then networked to display an image or text that can be read by people from a distance.
In addition, software had to be created that would allow those companies using EPD modules (both large and small) to be able to incorporate this technology into their own signs and displays very simply.
Over a number of years, that development and trialing has resulted in a stable working product that is suitable for use in various industries and markets.