Apple Inc.
SPHERICAL OR HIGHLY CURVED TOUCH-SENSITIVE SURFACES

Abstract:

A two dimensional touch sensor panel can be thermoformed or curved by another process to a three-dimensional touch sensor panel, and the three-dimensional touch sensor panel can be laminated to a three-dimension surface having a highly curved or spherical shape. In some examples, thermoforming a two-dimensional touch sensor panel into a three-dimensional touch sensor panel can result in strain of the touch electrodes, and can result in non-uniform three-dimensional touch electrodes (distortion of the two-dimensional touch electrode pattern). The strain can be a function of the curved touch-sensitive surface and/or process related mechanical strain from thermoforming. In some examples, a three-dimensional touch sensor panel can be formed with uniform area touch electrodes using a two-dimensional touch sensor panel pattern with non-uniform area touch electrodes in accordance with the strain pattern expected for a given curved surface and thermoforming technique.