Apple patent application outlines method of providing tactile feedback with a touchscreen

With the release of the iPhone, Apple brought multi-touch technology to the forefront. In March of 2006 Apple filed a patent application for a “Force Imaging Input Device and System” that appears to be meant to give tactile feel to touchscreen.

The patent application was published this week and outlines a touch pad that includes two sets of conductive traces separated by a spring membrane. Apple says when force is applied the spring membrane deforms, moving the two sets of traces closer together.

The patent application abstract goes on to say that the resulting change in mutual capacitance is used to generate and image indicative of the amount or intensity of force applies. The device says one or more inputs at the same time could be read.

The patent application describes a method where the amount of pressure applied to the touch pad would activate different commands or displays. One of the main complaints of the iPhone and most other touchscreen devices is that there is no tactile feedback to allow you to know when a button is touched or pressed.

Using the method described in this application, not only would tactile feedback be provided, but the traces that sense touch could activate one change and pressing the screen would activate another. This could be used to do things like change the color of a button when it is pressed, or initiate a vibration when the touch pad senses a touch to a button. When pushed, the tactile feedback would be there for the button press potentially alleviating the lack of tactile feel when operating a touch screen device.