In a second patent published this month, Apple describes adding touch nodes to future devices with curved or spherical surfaces
Earlier this month Patently Apple posted a report titled "Apple Patent reveals a possible Redesign of their HomePod by expanding its Light Display." The redesign included having a domed touch surface as presented in one of the patent figures from that patent below.
Yesterday the US Patent & Trademark Office published a patent application from Apple that continues this theme of touch sensors integrated into spherical or highly curved touch-sensitive surfaces.
Apple states that in some examples, a two-dimensional touch sensor panel can be thermoformed (or curved by another process) to a three-dimensional touch sensor panel (e.g., with touch electrodes having three-dimensional coordinates), and the three-dimensional touch sensor panel can be laminated to a three-dimension surface (e.g., a shell) having a highly curved shape (e.g., a curvature greater than a threshold).
Further, 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 (e.g., the shape and/or amount of curvature) 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.
Apple's patent FIG. 1 illustrates an example curved surface and one or more curved touch sensor panels; FIG. 6A illustrates a touch electrode pattern for a curved touch-sensitive surface; FIG. 5 illustrates a user touching a curved touch-sensitive surface.
More specifically to patent FIG. 5, touch-sensitive device can include a curved touch-sensitive surface (#502 shell) and curved touch sensor panel (#504) that can be thermoformed to fit the shape of curved touch-sensitive surface and laminated to the curved touch-sensitive surface (e.g., via a pressure sensitive and/or optically clear adhesive).
The curved touch sensor panel can be formed by thermoforming a two-dimensional pattern of touch electrodes (#506) formed on a substrate (#507). That can be formed of cyclo olefin polymer (COP), polyethylene terephthalate (PET), polycarbonate (PC) or other suitable material.
In some examples, touch electrodes can be formed using silver ink or other suitable conductive inks (e.g., copper, carbon-based conductive inks), conductive polymers, metal mesh, graphene, nanowires (e.g., silver nanowires) or nanotubes (e.g., carbon nanotubes).
In some examples, the touch electrodes and substrate can be flexible to allow for thermoforming without breaking or damaging the touch sensor panel. In some examples, touch electrodes can be laser deposited or laser etched on the substrate.
Apple's patent application, that was originally filed in Q3 2020 was published yesterday by UPSTO. One of the lead engineers that were listed on this patent is Supratik Datta, Engineering Manager: Touch Sensor Architecture & Modeling.
Considering that this is a patent application, the timing of such a product to market is unknown at this time.