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Power Cellphones Technology

Microsoft Researchers Use Light Beams To Charge Smartphones 65

angry tapir writes A group of Microsoft researchers has built a prototype charger for smartphones that can scan a room until it locates a mobile device compatible with the system and then charge the handset using a light beam. The researchers say they can achieve efficiency comparable to conventional wired phone chargers. The biggest barrier? Smartphones don't (yet) come with solar panels attached.
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Microsoft Researchers Use Light Beams To Charge Smartphones

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  • by Anonymous Coward

    Somehow I think they mean the case where the units of measure are the same not that the numbers are even remotely close. Just the overhead of operating the image processing system is going to make certain this is the case.

  • by ctrl-alt-canc ( 977108 ) on Monday January 19, 2015 @09:58AM (#48849273)
    ...to zap smartphones with a beam of light whenever they are not properly silenced.
  • by war4peace ( 1628283 ) on Monday January 19, 2015 @10:13AM (#48849351)

    1. Would infrared work just as well?
    2. What happens if the phone orientation is incorrect? Light beam reaches its side or the phone lies face-up.
    3. What happens if multiple phones are detected?
    4. What happens if the phone is turned off?

    • 1. Higher wavelengths have higher energy. So IR would be worse than visible light.
      2. Bad luck
      3. Could be configurable (or vary in differnt products based on this tech) Either a charching device with multiple beams, round robin or first come first served
      4. Your phone gets a big entrance in the spotlight.

      • 1. is irrelevant and wrong, rhe single ohotons have less energy, so you simply need more of them.
        We have 'solar panels' for IR that are far more efficient than we have normal solar panels for visible light.

        • Which means, that you have to create more of them. But I agree that you're right that the answer to this question depends on the characteristics of the panel.

          But to harvest IR, isn't the most common design to create heat and steam from sunlight and run that through conventional turbines? But that may be a matter of scale. A quick Google search didn't bring up any wavelength efficiencies, so I'm mostly making educated guesses here.

          • There was an article on /. about that technology, but with a missleading title ofc. so we can not really google for it. (something like: new break through in PV makes nearly 100% efficiency possible)

            A guy in a university is building such IR PV devices to harvest the heat energy combustion engines are radiating. The efficiency of them was very high, around 80% if I recall correctly.

      • 1. is irrelevant and wrong, the single photons have less energy, so you simply need more of them.
        We have 'solar panels' for IR that are far more efficient than we have normal solar panels for visible light.

      • Re: (Score:1, Informative)

        by Anonymous Coward

        > Q: 1. Would infrared work just as well?
        >> A: 1. Higher wavelengths have higher energy. So IR would be worse than visible light.

        No. In order to achieve optimum efficiency, you need to choose a wavelength with an energy per photon just slightly above the bandgap for the photodiode. If you use a silicon photodiode, IR-light of app. 950nm would work best.

        • by jandjmh ( 66714 )

          Used a mod point just because it is getting so rare to see technically knowledgeable comments around here. I wanted this to get noticed. AC is correct, silicon solar cells are at their best with wavelengths just a bit longer than visible. Same thing applies to LEDs. There are high power infrared LEDs that are better than 40% efficient at turning electrical energy into photons, and the last time I worked with them was over 20 years ago, so the state of the art may be even better now.

    • Re: (Score:2, Insightful)

      by Anonymous Coward
      5. When can we strap this to a shark.
    • by dabadab ( 126782 )

      Would infrared work just as well?

      Yes, it would, it's right there in the fine article.

  • If the charger can see your phone, it's not in your pocket or purse. So if you're not carrying it around, just stick it on a window ledge (for a much shorter time) or under an incandescent light source (we still have them, eh?)

    This also would not be for use outside the home - leaving it hang around to charge is a good way to lose it. Chargers are cheap - bring one to the office and everyone will love you when their phone is dying :-)

    • If the charger can see your phone, it's not in your pocket or purse. So if you're not carrying it around, just stick it on a window ledge (for a much shorter time) or under an incandescent light source (we still have them, eh?)

      Phone-sized PV cells, when provided broad-frequency light of typical ambient intensities, even full sunlight, produce very little output. That wouldn't charge your phone very quickly. With, for example, LTE radios on, it's unlikely it would even maintain the charge.

      If this system works, it's because they're aiming light of an intensity and frequency optimized for getting maximum power out of the PV cells. That's also the only way they could hope to get efficiencies anywhere near that of wired charging, ev

      • Easier to just leave a spare charger hanging around.

        The LED used is 2200 lumens, which is about the same as a 150 watt lightbulb. Whereas the light bulb spreads its light everywhere, this is concentrated into a small beam. So, do not look at charger with remaining good eye.

        • Easier to just leave a spare charger hanging around.

          That I can't agree with. The beauty of a long-range wireless charger isn't eliminating the effort of having to walk to another room to plug in, and it isn't even to eliminate the effort of having to plug the cord into the device. The real value is in eliminating the effort of paying attention to charge state or making decisions about when to plug in. Given an effective long-range wireless charger of the sort that these researchers are attempting to build, your devices would just always be fully charged when

          • I guess that's just another example of smart devices making us dumber :-(

            If you leave a charger at the office, it's not too hard to plug the phone in when you get there, or after lunch for a few hours. Solution cost is $10 or less. Same as buying a second adapter for your laptop and leaving it at the office - solution cost is around $40. Simple solutions that work, and when you go on vacation, bring your office adapters with you and even if you lose or forget them, it's not a big deal because you have one

    • If the charger can see your phone, it's not in your pocket or purse.

      Obviously this is just a cover story for research into a laser designed to melt people's phones while in use. e.g. if they don't put them away in a theater when the movie starts, or kids who won't put their phone away while in class.

  • by Chrisq ( 894406 ) on Monday January 19, 2015 @10:16AM (#48849375)
    Is "a laser capable of emitting a beam of pure anti-matter".
    • by Anonymous Coward

      Is "a laser capable of emitting a beam of pure anti-matter".

      Great Scott!

    • But to do that you need to reverse the polarity of the warp core and reroute through the main deflector dish. And we haven't even invented the warp drive or deflector technology yet. However charging cell phones wirelessly is the first valid need for such tech, so we at last have motivation to start working on it.
    • by fgouget ( 925644 )

      Is "a laser capable of emitting a beam of pure anti-matter".

      Photons are their own antiparticle [teachastronomy.com] so that part is easy. However, being massless photons are hardly matter.

  • And he said: "Phone, Where art thou?".
    Whereupon a light emerged; shining upon it like a divine revelation.
    And he saw that it was charging.

  • by wonkey_monkey ( 2592601 ) on Monday January 19, 2015 @10:27AM (#48849423) Homepage

    http://cdn.computerworld.com.a... [computerworld.com.au]

    That's the sort of thing one of my bosses would draw up in two minutes and say "See? Only eight boxes. It's easy. Now you go and make it work in half a day."

  • by Anonymous Coward

    How ~70% efficiency is comparable to 4% efficiency.
    I guess what they meant was time to charge.

  • I remember experimenting with wireless energy transfer with light back in my high school tech lab, so its not exactly a new idea. The emitter box was about the size of a 20 oz pop bottle sent a red laser into a receiver that that was about the size of a deck of cards. But with more up to date technology and some ingenuity they might be able to make it work for handheld devices. Despite the article I don't think solar panels on phones are the way to go, a very tight beam into a very small receiver (think

  • by Anonymous Coward

    The charger constantly rotates its camera and takes pictures until it finds a phone.

  • now airports will be crowed with people holding their phones up to lights instead of trying to scrounge every available outlet in the place to charge their phones. Imagine everybody with their arms raised.

  • TFA says: "Using a light beam to charge a smartphone could be as quick as many wired chargers, the researchers found, depending on the size of the PV panel."

    Efficiency is going to depend on the efficiency of the PV panel in the phone, but at 20% it's a long way off from the efficiency of a wired charger.

    The lengths to which people will go to avoid plugging in a wire still amaze me.

    • Shatter resistant glass and the proper cases make our electronics almost completely preschooler proof. However if the thing is plugged into the wall and they want to move it, the charging cable does not come out in any way that could possibly be called gentle. The Qi chargers look great on TV except that they can't charge through the protective cases. Why in the world they don't put a conductive material in the case so that it could, I don't know. Magnetic plugs would seem to go a long way. I've heard r
      • The Qi chargers look great on TV except that they can't charge through the protective cases.

        Shouldn't. They can and my girl friend frequently does with hers but you shouldn't as it reduces efficiency and causes the case to become "warm".

        Really though I don't notice any difference between her charge and mine (I don't have case)

    • You can subscribe to groceries at Amazon. I travel regularly for business. Wish they could include two micro-USB cables with my food delivery. Fortunately, they are now for sale in most airports for around $20. Business people end up paying that price now and again. Leisure travelers walk around begging to borrow one.
  • IMHO it is impossible to even come close to the efficinecy of a wire.
    With transformation losses and heat etc. the wire is still certainly above 85% efficiency.
    On the other hand, creating light is already below or at 85% efficiency and transforming it back to current with the very best 'solar cells' is at 48%. So bottom line we are minimum below 42%. That is less than half of the efficiency of a wire, without counting any further losses after the solar panel.

    • by dabadab ( 126782 )

      The most easiest way to explain is that it is made up by the submitter: this claim is not present in the linked article.

      What IS there is the following:
      "Using a light beam to charge a smartphone could be as quick as many wired chargers, the researchers found, depending on the size of the PV panel."

      It is certainly true, however, the best panels being rated at about 190 W/m2 max output you would need a PV panel about three time the size of an iPhone6 to charge it as fast as its wired charger does (or six times

  • Is it really so much of a brain-drain to plug your phone in to charge it everyday that we have to be wasting our time on stuff like this?
  • So if I put a picture of a phone on some other object, like the cat... ... and then program the indoor drone to attack the illuminated object... Seriously, just agree on a standard dock with conductive contacts that's easy to drop your phone on. How hard is that? The EU effectively made manufacturers agree on compatibility with microUSD.
  • Want to decrease your carbon footprint in a sane, achievable fashion?
    Stop WASTING resources ... at all levels.
    And 'remote' charging is so wasteful the mind boggles that it is done merely in the name of convenience.

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