A recent patent filed by Apple suggests the company is continuously looking for ways to improve user input devices. In this case, Apple describes an "improved feedback mechanism for touch pads", including "devices capable of illuminating the touch sensitive surface of the touch pad" and "methods for providing visual feedback at the touch pad."
Although touch pads work well, improvements to their form feel and functionality are desired. By way of example, it may be desirable to provide visual stimuli at the touch pad so that a user can better operate the touch pad. For example, the visual stimuli may be used (among others) to alert a user when the touch pad is registering a touch, alert a user where the touch is occurring on the touch pad, provide feedback related to the touch event, indicate the state of the touch pad, and/or the like.
Apple currently includes back-lit keyboards in its MacBook Pro notebook computers. The current application builds on numerous previous patents filed between 2002 and 2005.

The invention in a trackpad configuration.

The invention embodied as an iPod click-wheel.
Raw Data: Patent Application 20070152977