Future iPads -- and perhaps other iOS devices, though the Apple tablet seems the most natural fit -- could have e-paper features if an Apple patent (number 20110080417) is an indication. The patent is for systems and methods for switching between and electronic paper display and a video display.

Per the patent, control circuitry in an electronic device can analyze visual content to determine one or more features of the visual content. For example, the control circuitry can analyze visual content to determine the rate of change and/or color composition of the visual content. Based on the one or more features, the control circuitry can selectively enable the device's electronic paper display or the device's video display. The inventors are Gloria Lin and Andrew Hodge.

Here's Apple's background and summary of the invention: "This is directed to electronic devices with multiple displays. In particular, this is directed to systems and methods for displaying visual content on a combination of electronic paper and video displays.

"Traditional electronic devices include a single display for outputting visual content. For example, a traditional device may include a liquid crystal display (LCD) or organic light-emitting diode (OLED) display for outputting color visual content. In another example, a traditional device may include an electronic paper display for outputting black-and-white visual content using minimal power. The type of display included in a traditional electronic device is typically based on an assumption about the visual content it will most often display because different types of displays may be optimal, in performance or efficiency, for different types of visual content. For example, an LCD or OLED display may be optimal for high-resolution or dynamic color content while an electronic paper display may be optimal for relatively static black-and-white content. However, a traditional device may display multiple types of visual content even though its display may only be optimal for a single type of visual content.

"This is directed to systems and methods for switching between an electronic paper display and a video display based on at least one feature of visual content.

"Control circuitry in an electronic device can analyze visual content to determine one or more features of the visual content. For example, the control circuitry can analyze visual content to determine the rate of change and/or color composition of the visual content. Based on the one or more features, the control circuitry can selectively enable the device's electronic paper display or the device's video display.

"In some embodiments, portions of a device's electronic paper display and video display may be selectively enabled based on the visual content to be displayed in that portion. For example, an electronic device may divide visual content into different segments (e.g., different regions of a screen), analyze each segment, and then selectively enable a combination of electronic paper display regions and video display regions based on the visual content of each segment.

"In some embodiments, the electronic paper display and the video display may each be stacked vertically. For example, the electronic paper display can be stacked over the video display or the video display can be stacked over the electronic paper display. In some embodiments, an electronic device may direct the electronic paper display or the video display to configure itself to be translucent. For example, if an electronic paper display is stacked over a video display and the video display is selectively enabled, the electronic display may direct the electronic paper display to configure itself into a translucent state so that the video display is visible."

-- Dennis Sellers