The term “wireless” usually elicits a feeling of freedom when it comes to using our favorite smart gadgets without the baggage of, well, wires. But are we really wire-free? Wireless charging still requires you to plug in your charging pod, so technically there are wires involved. The solution? Laser.
This conundrum has led Engineers at the University of Washington to develop a long-range smartphone charger using laser technology.
How it works:
It involved firing a narrow, invisible beam from a laser emitter. This can charge phones without having to be placed in the same room. A thin power cell has to be mounted on the back of a smartphone in order for it to absorb power from the laser. It is supposed to be as good as plugging it into a standard smartphone charger.
Standard wireless chargers have to be within range of a few centimeters. The laser technology works between larger distances because it uses a focused beam of energy, whereas radio waves used in typical wireless chargers spread out in space and waste charge.
How safe is it?
The laser technology features the required safety precautions with the addition of a metal, flat-plate heat sink on the smartphone that dispels excess heat from the laser. The laser is able to shut off if it detects human activity through the use of guard beams which do not dispense charge but monitor movement.
The technicalities behind its safety:
Lower-power lasers that are incapable of burning human flesh are the solution. They mount retro-reflectors, which are three-sided cub-corners that have mirrored inner surfaces around photovoltaic cells.
The retro-reflectors differ from flat mirrors, which bounce light away at the same angle that it hits them. Conversely, retro-reflectors send light back to where it emits. These form a tube of light around powerful laser beams, essentially creating a barrier to its harmful rays. Anything can break this outer barrier, and the emitter stops the power to the main ray gun.
The team ensured that humans couldn’t be able to whip their hands fast enough to touch the actual charging laser by testing the speed of a professional baseball pitcher’s arm during a pitch. Everything else was determined through that velocity of speed.
Wireless charging method:
You can’t hear the phone being charged, as the frequency is inaudible to human ears. Microphones on the laser emitter are able to pick those noises and calculate the location of the phone. They take the ring of light until it hits the retro-reflectors, and when the signal comes back, the laser begins to charge.
How it works in everyday settings:
This all sounds great, but you’re probably wondering how it works in general capacities. When you place your phone down anywhere in a room, the laser will find the phone and beam its light into a photovoltaic cell.
What the team wants to accomplish:
They want to provide around 1 watt of power to a receiver that is the size of a pinky fingernail. They also want to offer a better wireless solution than the ones currently on the market. For now, it doesn’t look like laser beam charging will be on sale anytime soon.