Illuminating non-self-lighting displays
The new e-ink display technology is showing up a few issues here, especially with use in darker environments. The typical solution for dark-environment ebook reading was to use an accessory cover that had an integrated light of some sort. But it will follow the same path as the liquid-crystal display as I outline below.
Initially, if an application required any form of useability in a dark environment such as a watch, the manufacturer installed a filament bulb in the side of the display and this was lit up by the user pressing a button. Later on, in the mid-80s, device manufacturers used a LED array installed behind the display to backlight small displays like number displays. This typically provided a relatively-consistent illumination effect across the display area and allowed for such practices as changeable illumination colours, which was asked for with car radios.
This became the norm through the mid-90s until some watch manufacturers worked on the use of “electroluminescent” illumination technology which provided an illuminated display on their watch with very little battery consumption and an even display lighting.
Large LCD screens for video / data display applications do use cold-cathode fluorescent backlighting but have moved to white-LED backlighting as a way to be power-efficient.
Research that has been done
The current problem with the e-ink display is that it isn’t self-illuminating. This is although there is research by Pixel QI in to establishing a display technology that can combine what the LCD offers with the e-ink technology. This is to counteract the problem of LCD and OLED display applications being “washed out” in bright sunlight.
But there could be the use of a white electroluminescent panel behind an e-ink display, especially a colour fast-refreshing type to allow for a highly-flexible “use-anywhere” display that can conserve power.
Once we see further work on the e-ink display taking place, it could then allow for this technology to move beyond the Nook or Kindle e-reader.