Apple has patented a new display technology that will allow their iPhones to have always-on displays with almost no battery cost whatsoever. This doesn't mean the whole display would be lit at all times. In reality, only part of it would be activated using a secondary backlight system located under the main one. According to Apple, the objective is to give feedback to the user at all times, even when the main display is turned off:
The primary backlight system may block light from the secondary backlight system except for those one or more regions. Thus, the size and shape of the status indicator may be set by sizing and shaping the transparent or semitransparent regions of the primary backlight system. In addition to setting the size and shape of the icon, the colour of the icon may also be set by adjusting the colour of the light provided by the secondary backlight system.
For example, each indicator may have a particular colour, blinking speed, or light intensity. These properties may be programmed into the electronic device by the user, or may be hard-coded or hard-wired into the system. Thus, when the secondary backlight is turned on, the properties of the light provided by the secondary backlight system may depend on the status of the device. Also, if the status of the electronic device changes while the secondary backlight is on, the properties of the light provided by the secondary backlight system may change to reflect the new status.
To avoid depleting the battery, these icons' backlight system will be low-power. Don't get your expectations too high, however. The patent doesn't clearly explains how the icons themselves may be displayed. By the look of the diagrams included, they may not even be actual pixel-based icons, but cut-outs illuminated by individual LED lights shining through the main display.
But of course, you know that this may be something completely different from what the diagram shows, since the drawings included in patents always seem to be drawn by a monkey on drugs. At least, I want to believe this thing is more like the illustration I did, because if it's just little icons—like every other single cheap clamshell mobile phone out there—I won't be very excited. [Apple Insider]