Patent attributes
A device including an elastic layer that, when depressed by an object, causes a local indentation in the layer, the geometry of the local indentation being in accordance with a force of depression, light emitters, light detectors, a light guide between the emitters and the layer directing light beams from the emitters into the layer at an angle such that the light beams, after entering the layer, remain confined to the layer by total internal reflection, a light guide between the detectors and the layer that directs light beams exiting the layer onto the detectors, each detector having a reference output value corresponding to expected light detection when no object is touching the layer, and a processor determining the object's force of depression based on the geometry of the local indentation in the layer, as calibrated by a deviation between actual and reference output values for one of the detectors.
