“With Apple’s U.S. Patent No. 8,730,179 for an ‘Integrated touch sensor and solar assembly,’ the company offers an alternate take on an hybrid solar system that can be disposed beneath a large touch panel and even flexible displays,” Campbell reports. “The basic design uses a transparent double-sided ITO (DITO) substrate overlaid atop a solar panel cell array, which then translates light energy into electricity that can be stored in the onboard battery. A modification to the original property includes an arrangement in which a flexible single-sided ITO (SITO) substrate can be employed over a similarly flexible polymer solar cell panel.”
“Unlike the previous version of the invention, the solar panel may be mounted face-down in the stack-up, meaning it would be facing away from the user and back into the device. Due to this change, in some embodiments, the solar panel cannot act in an “optical sensing mode” where the array itself could be used instead of, or in concert with, the capacitive touch layer,” Campbell reports. “When facing away from the touch sensor array, the solar panel must have light piped into the device via light channels.”
More info and Apple’s patent application illustrations, in the full article here.