Service automation devices are becoming more commonplace to speed up processes and even prompt us to rate the service we’ve received. Such devices benefit from a screen to display a phrase or command and, when designing one, more and more engineers are using E-Paper Displays (EPDs).
Author: Scott Soong, CEO Pervasive Displays
EPDs, traditionally associated with e-book readers, are recognisable from their natural-looking off-white surface and graphite-like imagery. Service automation is just one of many applications that are well suited to EPD technology. Besides the readability of EPDs – even in direct sunlight – they are power efficient when compared with LCD or OLED alternatives.
Battery-operated devices need to possess ultra-efficient power management to function as a portable device. E-paper has the advantage of consuming power only when the image on the screen needs refreshing. This means that after a refresh, the image remains on the screen indefinitely without consuming power.
Energy-harvesting schemes are not out of the scope of EPDs. Near-field and RFID power pulses conceivably carry enough energy to update an EPD. Energy harvesting makes e-paper a candidate for ‘no-power’ or ‘small battery’ designs.
The secret to e-paper is in the use of E Ink technology. An EPD consists of two transparent charge plates, between the plates are millions of microcapsules filled with electrically charged pigment capsules. With the application of a negative charge to the top plate, the positively charged white pigment floats into view. Conversely, a positive charge applied to the top plate will attract the negatively charged black pigment. Removing the charge causes the particles to remain static. This holds the image on the screen until the next image refresh, without using power.
As well as the power efficiency of EPDs, they also have a weight advantage over LCDs or OLEDs. EPDs are lighter and thinner than LCDs of similar size. Lighter weight and thinner mechanical profile are of considerable benefit to designs that may have to be hand held or mounted on a surface with little support.
One can apply e-paper displays to countless designs. Where mains power is scarce, outdoor visibility is essential and lightweight design is a must, an EPD aims to be a viable solution. Applications span from service and infrastructure automation to logistics and IoT (Internet of Things) – and much more.