“Superlens” may solve wireless charging dilemma

http://techpageone.dell.com/downtime/superlens-may-solve-wireless-charging-dilemma/#.Ut4mWmS6b-k

by jjude • 13 years ago

54 51 13 years ago

techpageone.dell.com

Seems like we can all just unshield our microwave ovens and fry two birds with one dosage of cancer-inducing electromagnetic waves. Honey, dinner's ready and your phone is charged. Little Alex is vomiting again and his hair is all over my new dress!

mstromb• 13 years ago

You seem to have confused non-ionizing radiation (http://en.wikipedia.org/wiki/Non-ionizing_radiation#Health_r...) (the type mentioned in the article) with ionizing radiation (http://en.wikipedia.org/wiki/Ionising_radiation#Biological_e...)

While some sources call into question the health effects of EM radiation, radios aren't causing vomiting and hair loss unless they're also made of radium.

david927• 13 years ago

That's what jumped out to me as well -- I have a huge concern for the potential ill effects to the human body. Plugging in a device is not a huge hardship and is vastly over-shadowed by the potential health risks.

XorNot2• 13 years ago

It really isn't. For one thing, your body doesn't respond to magnetic fields at all.

userbinator• 13 years ago

It already astounds me greatly how much common people don't know the basics about EM fields when we've essentially been immersing ourselves in them for over 100 years.

The main danger is power level causing heating/burns - and a microwave operating at 1000W+ is going to do that far more easily than a router with 1W at most.

option_greek• 13 years ago

Sounds like a fresnel lens for electromagnetic waves.

namuol• 13 years ago

The problem is that our devices need frequent charges, not that plugging in is especially inconvenient; this battle will be won on the battery-life front.

deletes3• 13 years ago

Imagine a charger that homes in on your mobile devices and charges them to a certain distance, without harming objects in between the source and destination. That way you could have them everywhere and battery would be hardly needed.

simonh• 13 years ago

Because what I really need in my life is high energy radiation beamed directly at an object I generally keep a few cm from my reproductive organs.

venomsnake3• 13 years ago

On the speed of charge front. Current battery capacity is fine. What we need is the ability to charge it for 30 seconds. So maybe supercap based batteries?

manmal• 13 years ago

Or smaller capacitors.

rplnt2• 13 years ago

Current battery capacity is fine.

If it is, then consumption is too high. Few hours of use is not "fine". Sure, if I use it as just a phone it can last week.. but once I use it as a computer, it drains pretty quickly.

weland• 13 years ago

Supercap-based batteries have other problems that make them similarly inconvenient. Current battery capacity is far from fine, considering that a smart "mobile" phone can barely last through a delayed plane trip.

ddeck• 13 years ago

Even without new technology, I wish more devices incorporated current fast charging tech.

My X1 Carbon laptop may not have the world's best battery life, but being able to recharge it to 80% in ~30 minutes is fantastic. It's saved me on many occasions when I've been heading out of the house and realized that I forgot to charge it or needed to charge in a coffee shop where I couldn't sit near the outlet.

I can only assume the lack of this charging speed in most products means that it's either quite detrimental to the battery longevity or the cost/weight of the electronics outweighs the benefit, or both.

gnur• 13 years ago

When I was using the Nexus 4 I would always put it on my desk when working. I put a wireless charger at that position and had no need to plug it in for at least a few months. I never had to think about the charge because I was at my desk often enough for my phone to get charged.

beggi• 13 years ago

If we're talking about day-to-day battery issues in regards to devices like phones and laptops, the battle can be won on number of fronts, for example:

1) Batteries get enough capacity so you only need to charge them once a month.

2) Batteries can be fully charged in a short period of time, say one minute, we wouldn't bothered very much to have to plug them in once a day.

3) Carrying around a device at home or work for few hours a day will keep the device charged for a whole day (via the "superlens").

Any of the aforementioned solutions and perhaps few others would solve the issues we have with batteries in our handheld devices today. For cars, trains and other battery uses, that's another thing.

nodata2• 13 years ago

Have you used a wireless charger?

You don't really charge your phone, you just put it on an allocated area of your desk.

prof_hobart2• 13 years ago

That's still something that

a) you need to remember to do (my phone currently lives in my pocket at work when not in active use) and to undo - i.e. pick it up again when you wander off

b) needs you to be near your desk at some point. I can often be away from any power source for many hours at a time - more than long enough to drain an average smartphone's battery with reasonable use.

exo762• 13 years ago

Dilemma, really?

noun noun: dilemma; plural noun: dilemmas 1. a situation in which a difficult choice has to be made between two or more alternatives, esp. equally undesirable ones.

#firstworldproblems

cmdli• 13 years ago

Dilemma, noun (3b): a difficult or persistent problem.

http://www.merriam-webster.com/dictionary/dilemma

qq66• 13 years ago

Seems like the type of problem that will be solved in order to sell products to those too lazy to plug in their phones, but in doing so open up entirely new possibilities in medical devices, remote sensing, and other areas.

nardi• 13 years ago

Does anyone know what happened to magneto-resonance? That sounded like the way wireless charging was going to go a few years ago.

zymhan• 13 years ago

I had no idea Dell had a blog with actual writers.

svantana• 13 years ago

I don't see how transmitting the power 10 inches would make charging any easier.

The MIT spin-off WiTricity has been working on a better(?) solution since 2007, they have been consistently overpromising and underdelivering, but recently they showed this nice-looking device: http://gigaom.com/2014/01/09/video-wirelessly-charging-your-...

Personally I believe it would need a few meters' range before it becomes really useful - the point where you rarely need to consciously charge your phone because it is always charging when you're at home.

rjdagost• 13 years ago

I was really interested in Witricity and read a few related papers on their technology. There are a few problems that they are not so keen to publicize:

(1) If the receiver loop isn't "inside" the transmitter loop along the normal of the loop area then efficiency falls a bit (2) Efficiency depends a lot on the orientation of the device being charged. If the receiver loop isn't very nearly coplanar with the transmitter loop, efficiency bombs (3) Range is fairly limited (4) When you have multiple devices charging concurrently, efficiency falls for every individual device being charged as magnetic resonance cannot be achieved nearly as well for more complicated multi-body flux loops

Witricity has been trying to push electric car charging as for that application these downsides don't matter as much. But even there, you get something like 50% efficiency. Do you want to nearly double your electricity costs just to avoid plugging in a cable? Interesting technology, but it doesn't see like a worthwhile proposition to me.

General purpose wireless power transmission is a really difficult problem. I was interested in the ultrasonic acoustic approach that uBeam is pursuing but that has its own slew of problems.

tlarkworthy2• 13 years ago

Does anybody know how people come up with the metamaterial designs? Do they just try lots of aesthetically pleasing symmetries out until they find one that works?

Or do they have some forward model to predict the outcome before they build it, but given the often inexplicable results that doesn't seem possible.

Where do the ideas come from?

triplepoint217• 13 years ago

Yes, we do have some pretty good theories for designing metamaterials. From what I can remember (and quickly look up on the net), one of the leading theories is called transformation optics, and finding a coordinate transform to a coordinate system where the path you want light to take is a straight line. You can work out what your metamaterial has to look like from that coordinate transform.

I probably have some of the details of the technique wrong, I am trying to remember a talk from a year ago. If you want more detail, look at John Pendry's papers (he is probably the leading theorist in metamaterials). http://www3.imperial.ac.uk/people/j.pendry

tlarkworthy2• 13 years ago

oh hot. Thanks a lot. Sounds like another win for eigenvectors :p

cincinnatus• 13 years ago

The whole push to wireless charging feels like a bad idea. We already are deeply in need of reductions in total global power use or at least efficiency improvements, and wireless charging wastes a huge amount of power. Unless they can figure out how to bring the efficiency in line with direct contact we're better off with clever direct contact without a plug schemes.

HillRat• 13 years ago

This -- the fact that even highly-optimized inductive charging is about 85% as efficient as direct-contact DC seems to get ignored a lot.

Having said that, I actually understand the appeal of charging mats and the like, because they replace a small but persistent friction (find a charger, plug in the charger, plug in the phone, unplug the phone, plug the phone back in...) with a near-frictionless experience, if you don't count the cost. I'd like to see better conductive charging designs, but it looks like inductive has won out.

“Superlens” may solve wireless charging dilemma

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