US Patent 9024908 Tactile feedback display screen overlay

Systems are disclosed for an optically clear keyboard that can be applied to a touch-sensitive display screen, for example, while mitigating distortion of the display. An apparatus for use over a touch-sensitive display screen can comprise a plurality of button structures formed of an optically clear material. The buttons are disposed in an optically clear fluid or gel having an index of refraction equivalent to the index of refraction of the button structures. The apparatus comprises an optically clear elastomeric membrane over the fluid, which forms a sealed barrier for the fluid or gel. The volume within the sealed portion of the apparatus contains the fluid and the button structures.