A new film could greatly improve lighting on electronic paper devices. In the video below, Flex Lighting demonstrates the system, which works by distributing light from one or two LEDs across a very thin light guide laminated to the surface of the screen. The company claims the film works with both monochrome and color displays, can be switched on or off as needed, and uses minimal power. Indeed, the demo seems to work well — the screen isn't obscured when the film is turned off, and when turned on in the dark it provides a clear view of the text. Those intermittent screen blackouts during the video appear to be standard electronic paper page refreshes, not any kind of problem with the light.
While it's not the first internal e-reader light, the film provides a smoother, more consistent glow than current solutions, which work by embedding individual LEDs into the edges of the screen. It's probably most similar to this light-guiding tape, which is used to smooth the lighting in edge-lit monitors. Flex Lighting's site doesn't list any partners for its product, so it's unclear when and if we'll be seeing these lights incorporated into existing technology, but this early demonstration shows its potential for e-reader integration.