Apple plants flag on wireless power-supply map
Near field charging works well enough for keyboards and mice
Apple has fenced off its own little patch of the wireless charging space, with a patent covering the use of “near field magnetic resonance” (NFMR) to wake up low-power peripherals like keyboards and mice.
Apple’s contribution to the art is disclosed in “Wireless power utilization in a local computing environment” here.
Far from being a Great Leap Forward© to a world where tablets and phones will be free from their wall warts, the application makes it clear Cupertino knows the limitations of over-the-air power. The claims of this particular patent envisage just keyboard and mouse, with the possibly-nifty but inefficient idea that if the keyboard is getting more power than it needs, it could retransmit power to the mouse – or vice versa. You can discern a little of the intent in the illustration, drawn from the patent application, below at right.
And there’s always the question of “how do we control the market so that the peripherals carry our name?”, which seems to be answered in this passage from the patent:
“a plurality of peripheral devices each having a tunable resonance circuit suitably adapted to receive power wirelessly from the NFMR power supply, wherein when at least one of the plurality of devices is within range of the NFMR power supply, the device tunes the resonance circuit to at least one of the resonance frequencies of the NFMR power supply and subsequently de-tunes the resonance circuit to provide a device identification to the NFMR power supply using a change in a resonance circuit load factor.”
In other words: the charging unit will only work with identified devices. ®