US Patent 8031174 Multi-touch surface stackup arrangement

A multi-layer cover for an electronic device having one or more of a sensor panel, a proximity sensor, an ambient light sensor, and a display device can include an outer hardcoat, a structural layer, an IR transmissive ink layer, a mask layer, and a backside hardcoat. The backside hardcoat can reduce cover warpage, enable full surface lamination of the cover to the sensor panel, prevent bubbles from forming in transparent windows in the cover, enable a wider range of functional inks to be applied in various layering orders to allow certain types of light to pass through while blocking others, and hide the sensors to provide a seamless, uncluttered visual appearance.