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Solar-powered iPhone on the way?

Engineers behind Apple's iPod file a patent application regarding the integration of solar cells into the displays of portable electronic devices.

Apple has taken a shine to using solar cells in its mobile devices.

A patent application, unearthered by, describes technology to integrate solar cells into portable devices. The named inventors of the patent application are Apple employees, some of whom are iPod engineers.

Images from an Apple patent for solar cells in portable devices. U.S. Patent & Trademark Office

Using small solar panels to charge portable devices is nothing new; there are several such products already available. Apple appears to be trying to innovate in the integration of the solar cells into a portable device.

Rather than make a separate charger, Apple engineers have sought to package solar cells right into the device in an unobtrusive way. Electricity-generating cells could be placed underneath the device's display. Specifically, the patent application details the use of a semitransparent display with a solar cell placed underneath it.

Sandwiched together, the device's cover would have "at least one glass layer coupled to the solar-cell layer; and a flexible printed circuit board (PCB) layer coupled electrically and mechanically to the solar-cell layer," according to the patent application.

This integrated design would allow the mobile device, be it a PDA or portable music player, to be charged from daylight without having a separate solar panel that needs to be plugged into it.

In a patent application, Apple engineers envision a solar panel integrated into a portable electronic device. U.S. Patent & Trademark Office

The patent application also describes using multiple solar cells coupled to specific electrical components within a device, including the data-processing system and the memory.

Drawings from the patent application show ways that a solar cell could be placed on the back cover of a device.

Electricity generated from the cells would be fed to the device's rechargeable battery.

In an older patent, Motorola sought to build a display that would allow enough light in to reach solar cells that charge a device. Its display calls for "organic light-emitting diode displays, and touch-sensitive displays are stacked with one or more solar cells."

Having a solar cell integrated into a display or cover makes the device more likely to absorb light than if the panel is placed on the back.

More significant, though, are the attempts by Apple and Morotola to package a solar cell into a device.

Separate solar chargers can be small, but they add to the number of items consumers must carry around. Also, many solar chargers are essentially just small solar panels without the ability to store electricity for later.

What remains to be seen is how much power an integrated cell, hid behind a display, can generate. This is dependent, of course, on the availability of light. But most likely, any solar-powered iPod or iPhone would include an AC adapter for standard charging.