Apple has filed for a patent that indicates the company may be considering the use of a touch screen on other devices besides the iPhone, which is scheduled to ship next month.

The patent request, filed Thursday with the U.S. Patent and Trademark Office, shows blueprints for placing a touch-sensitive screen on the backside of a device for control purposes, leaving the front side for presenting information appropriate to the device, such as video.

The filing sparked speculation among tech bloggers that Apple could be considering the use of a touch screen on the iPod. Apple, which has a policy not to comment on future product plans, was not immediately available for comment.

According to the patent application, the touch screen would have a cursor that would follow a person's finger. Once the cursor was above a control element, the user could apply pressure to activate the associated function. As a result, the device could be operated with a single hand.

The front of the device would be used for displaying video, graphic or textual information, while the back would have the control elements, which could include a QWERTY keypad, sliders, and control wheels, the application said. Apple listed a number of devices that could use the backside touch screen, including handheld computer systems, tablet computer systems, personal digital assistants, portable video or audio playback systems, and mobile telephones.

To date, Apple has only announced plans for a touch screen on its iPhone, which the company unveiled in January at Macworld in San Francisco. The iPhone introduction has drawn lots of attention toward Apple, and its hopes of creating a product line that matches the popularity of the iPod.

Rivals looking to grab a bit of the spotlight are claiming to have their own surprises coming. Ed Zander, chairman and chief executive of Motorola, said this week at the Software 2007 Conference that his company would be showing a device next week that's a "media monster," capable of running video at 30 frames per second off secure digital memory cards pre-loaded with movies.