A New Wireless Power Transmission Sheet

Roland Piquepaille writes "Several companies have started to sell power 'pads' that can charge your cellphone when you put it on the pad's surface. But these silicon-based pads are expensive — and relatively 'specialized.' Now, Japanese researchers have built a plastic sheet which could power all the devices placed close to it. So far, this 4-layer sheet, which uses printed organic transistors and plastic MEMS switches, can deliver up to 40 watts of power — enough for some laptops. The technology is apparently efficient and inexpensive to produce. But as the devices to recharge will need to incorporate a special receiver, don't expect to see these plastic power sheets on sale before several years."

i remember this

[brunascle]

i remember this [technologyreview.com]. good to see it's making its way to the market.

Given his reputation...

[Anonymous Coward]

this one's tagged "fuckroland ohnoitsroland pigpail pigpile shill"

How Efficient?

[FroBugg]

The article gives some efficiency numbers, but doesn't explain exactly what they're talking about.

The researchers say the transmission of power happens with 81.4% efficiency -- compared to 93% efficiency in the wired grid network as a whole -- with a "quite low" level of leaked electromagnetic radiation.

Now, I may be wrong, but I believe that 93% is the efficiency of electricity being generated at the power plant and then sent to you, however many miles away. So it's not an either-or thing, it's an extra loss. Instead of losing 7% of the generated electricity, you lose nearly 25%. This is ridiculous compared to the effort of just plugging your damn devices in.

Re:i remember this

[OldeTimeGeek]

If the brush that they're using is a Sonicare, there aren't any contacts - it uses inductance.

Re:How Efficient?

[FroBugg]

http://www.inference.phy.cam.ac.uk/sustainable/cha rger/ [cam.ac.uk]

Re:40 watts?

[mobby_6kl]

My laptop's PSU is rated 2.7 A at 18.5 Volts, and that must be with a good safety margin. Then agian, it's an almost six-year-old, 600Mhz P!!!-M machine, with 3D Rage Pro for video and an 11" screen.

Mordern laptops, judging by the replacement PSUs available, seem to fall between 65-100W, although one Acer unit is rated at 135W.