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Science

Photonic Structure Increases Light Bulb Efficiency 226

Posted by Hemos from the bulb-bulb-burning-bright dept.
An Anonymous Coward writes "A new experimental microscopic tungsten lattice can increase the efficiency of an incandescent electric bulb from 5 percent to greater than 60 percent. This is done by converting waste heat into visible light. "
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Photonic Structure Increases Light Bulb Efficiency More

Photonic Structure Increases Light Bulb Efficiency

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  • Question (Score:2, Troll)

    by friday2k ( 205692 )
    According to the article "The work was performed with a photonic crystal operating in the mid-infrared range". Though the author states further that there are no known obstacles to downgrade into the visible light range, why did they start in the Infrared spectrum to begin with?

    • Re:Question (Score:3, Funny)

      by ErikZ ( 55491 )
      IR seems to be the first thing people get when they're working with things that produce light. I believe IR LEDs were the first LEDs, and IR lasers were the first light emitting lasers.

      Second, I love this. They don't even have a THEORY on why this works. It just does.

      Third, If they get it working in the visible light spectrum, they'll have a bulb that's SIXTEEN time more powerful than tungsten bulb.

      That's one hell of a flashlight. I'll call mine "Little Boy". I promise to only use it in self defense. And to start small fires.

      • Re:Question (Score:5, Informative)

        by maraist ( 68387 ) <michael.maraistN ... m ['AMg' in gap]> on Sunday May 05, 2002 @09:58AM (#3465388) Homepage
        Second, I love this. They don't even have a THEORY on why this works. It just does.


        Well, I'm an undergraduate Electrical Engineer, so I only have superficial understandings of how semi-conductors interact with light, but it doesn't seem too great a stretch of the imagination.

        First, semi-conductors work based on the principle of the band-gap (which they even mentioned) (correct me if I'm wrong with any of this, I'm doing it straight from rusty memory).

        A little background:
        The outer 8 electrons held by an atom are the most important (the valence) - They are responsible for the bonding of other atoms. The configuration of all the electron orbitals in free space is nicely geometric; the first two electrons form a spherical shell (s-shell), the second 6 form dumb-bells in each of three axis's (p-shell). These types of configurations affect the geometries of the connection of the atoms. Configurations get more complex as the number of electrons grow (which is somewhat independent of the atomic number (number of protons), but such ionized atoms are unstable; especially when the number of electrons differs dramatically from the #protons). The important thing to understand here is that each additional electron takes more energy. Instead of worrying about the geometries, you can plot each electron orbital at a different (successively higher) energy level. Different atoms (characterized by atomic-number and even, to a small degree, the number of neutrons present), have differing characteristic energy-levels. The discrete nature of atoms includes the probabilistic nature wherein electrons have an extremely high probability of occupying the exact energy levels (which can be thought of as the distance away from the center of the nucleus). There is a chance that an electron will pass through any point around the shell of an atom, but it's highly unlikely that it will deviate from its characteristic point.

        But, since different atoms have different characteristic levels, warping an atom will warp its points. Warping can occur by simply placing two atoms near each other (such as in an ionic or covalent bond). As it happens, when you squeeze atoms closer and closer together, the discrete lines that represent the energy levels start to merge together. Eventually the 8 outer valence bands merge into one continuous band... As you squeeze them even closer together, this band breaks into two continuous pieces. As you get even closer together, these pieces get further and further apart (I would presume that eventually one of these bands starts to merge with preceding energy levels, but that's not relevant here). This gap of continuous energy levels is called the band-gap.

        As it turns out, in perfectly bonded atoms (those where every electron in the valence layer are bonded, and each atom has exactly 8 outer electrons; such as carbon, Silicon, etc) we have a total of 4 electrons that fill the inner continuous shell and 4 electrons that are void in the outer continuous shell. BUT, that outer shell is looped across neighboring atoms. When a diamond-lattice is organized (which is as close as you can possible get multiple atoms to sit next to each other), you have the greatest band-gap you can get for that particular element. Different elements (or even molecules) that can form the diamond-lattice will have differing characteristic band-gaps. What we have here are 4 electrons that are tightly tied to a core atom, and 4 potentially absorbed electrons that can freely be shared across every single atom in the entire crystalline lattice. In semi-conductor crystals, the problem is that every electron is accounted for so there are no free electrons to put into the outer band (which could roam free as current through an almost zero-resistance substrate; due mostly to quantum effects). Impurities are therefore inserted into the crystalline lattice which act as ionic donators of electrons or ionic acceptors of electrons (namely atoms not in the 4-column of the periodic table). Thermal excitation (heat) causes an electron to be ripped from donor atoms and those which are then quickly swept up in the outer-most continuous band.

        Normally, electrons must have a precise energy-value in order to live in an atomic orbital. When an atom absorbs an electron, it gives off a photon of the remainder of the energy. To change orbital-levels, it has to accept a photon of exactly the correct amount of energy. It can accept a larger energy photon, but it will again give off the remainder of energy. Eventually that excited electron will fall back to its lower energy level, giving off another photon which will have the exact energy as the distance between the two energy levels.

        In the continuous region of these silicon atoms, excitation between energy levels isn't apparent, since an electron can have any value within the region. The only difference is that separating the band gap... An electron from the inside can jump into the outer band if it's given at least enough energy to make the jump... This gap is usually enormous for semi-conductors. I believe its 1.2 electron Volts for Silicon, and 10 electron Volts for Carbon. The 1.2V is within the range of thermal excitation. That means that heat (in the form of vibrating atoms in the crystal) is enough to shake an electron free; e.g. jump the gap (like water successfully spitting to the lid of a boiling pot). In carbon, however, room-temperature heat is no where near enough to make the jump. This property (along with others) is why we don't use carbon-based semi-conductors. Germanium and silicon are much more practical in our particular earth climate.

        There is another aspect to the band-gap that is relevant to our discussion. Each electron has not only an associated energy, but a quantum-form of momentum. You must not only have conservation of energy, but conservation of momentum. I'm a little fuzzy on this topic, but this momentum is represented by the letter k, and we can plot energy verses k for different things. For semi-conductors, we get parabolas, and inverted parabolas, but with discrete points. This says that while we have a continuous set of energy levels within a region, we have only a certain set of allowable energy+momentum values for the electrons. And like the discrete energy levels of atomic orbitals, you can only have one electron occupying a given state. In a rather unfulfilling way, I'll stop talking about things that I don't fully understand and simply say that this multitude of characteristic parabolas says that in order to have an electron jump, you have to not only have a precise amount of energy absorbed or emitted, but you have to be able to transition your momentum somehow. Energy transition occurs through photons, and momentum transition occurs through phonons - which is energy present in lattice vibrations (e.g. packets of heat).

        Gallium arsenide is an example where the lowest point of the upper parabola and the highest point of the lower inverted parabola are aligned with respect to momentum. This means that the smallest amount of energy needed to make an electron jump the gap requires zero change in momentum. Because of this, gallium arsenide crystals easily will easily absorb or emit light with no dependence on the heat of a lattice. For this and other reasons, GaAs is great for laser diodes. Silicon, on the other hand requires a momentum change for its lowest energy transfer. Thus lots of heat is generated and absorbed; (Not to mention that silicon doesn't conduct heat as well as some other semi-conductors).

        Given this superficial description, what I get out of this is that heat of a certain resonant point (in the form of vibrating atoms in the crystal) could provide the proper momentum shift needed for efficient electron excitation. You'd still need to provide photonic energy for the transition, but you'd have a perfect combination of heat + light absorption. Eventually (due to statistical decay), the electrons would fall back to their lower-energy-level states. But they'd give off light of specific frequencies.

        Putting all this together, my initial impression from the article was that that the tungsten injection into a silicon substrate change the characteristic e-k curves enough to absorb the phonon-heat generated by IR light. The result is a 60% efficient absorption of the heat + light (e.g. nearly perfect efficiency). That energy is retransmitted as diode light (e.g. an exact energy level transition, producing a constant level of energy photons, which requires an equally constant frequency of light).

        What I don't know at the moment is if this is actually emitting mono-chromatic light, or if a multitude of frequencies (e.g. white-light) permeates. The only way I could see white-light emitting is if the standard tungsten light-bulb is making it, and the Tungsten semi-conductor is amplifying a particular frequency.
      • That's one hell of a flashlight. I'll call mine "Little Boy". I promise to only use it in self defense. And to start small fires.

        Yeah, I always wanted a flashlight strong enough to kick when you turn it on... ;-)

    • Re:Question (Score:3, Informative)

      by stinkydog ( 191778 )
      Infra Red is a lower (longer) wavelength than visible light. It makes sense to get it to work at the lower (probally easier) wavelegnth and then 'take it up a notch' into the visible spectrem. This is exciting for it's energy efficiency and the fact the light remains a point source (good for fixture design).

      I wonder how the matrix holds up as the tungsten evaporates from the filiment?

      SD

      • Re:Question (Score:2, Insightful)

        by nicktook ( 74274 )
        Seems to me the heat does not build up. That seems to be the point. Obviously some heat is produced but if the filament does not get very hot then the tungsten should not evaporate. The bulb may have a very long life.

        The article leaves a lot of unanswered questions. I suspect the scientists are more interested in the phenomemom than its practicality.
        • The bulb may have a very long life.


          Yeah, I thought of that too. These bulbs would be able to produce the same light running on far less electricity and last practically forever. Guess those florescent bulbs are doomed now.

    • I understood that they want to transform IR into visible light somehow.

    • Re:Question (Score:3, Interesting)

      by maraist ( 68387 )
      My understanding is that they said that IR-frequencies are synonymous with "heat". They frequently used the term black-body radiation. I remember IR-HEAT being associated with green-house effects; the angle of refraction is low for IR and glass, for example. So when sunlight enters your car (at a direct angle), it bounces off things but hits the glass on the inside at too great of an angle, and thus bounces back inwards, amplifying the total heat.

      Not that I'm satisfactorily answering your question, but throwing out some food for thought.

      -Michael

      • I think the greenhouse effect has more to do with absorption than with angle of incidence. Blackbody emission peak wavelength decreases with temperature. The Sun, a 6000 K blackbody, emits visible light, which passes through the windows and is absorbed by the interior. The interior, a 300 K blackbody, emits infrared, which is absorbed by the windows.

        In his autobiography, 19th century instrument maker John A. Brashear [clpgh.org] describes a project to make lenses out of salt crystals for an astronomer who wanted to make infrared observations. Salt is supposed to be much more transparent than glass in that band of the spectrum.

    • Re:Question (Score:2, Insightful)

      by 26199 ( 577806 )

      I think you'll find operating in the infra-red range was the point - it absorbs what's in the infra-red range, which is good, because that's what you want to get rid of.

      The absorbed energy can then be re-emitted at visible wavelengths...

  • Sorry.. (Score:4, Funny)

    by petis ( 139263 ) on Sunday May 05, 2002 @08:31AM (#3465218)
    couldn't resist:

    Q: How many programmers does it take to change a broken light bulb?
    A: None, it's a hardware problem.

  • Easy Bake (Score:1, Redundant)

    by flipper9 ( 109877 )
    If this goes through and they manufacture these cool, efficint bulbs, how will I get get my Easy Bake Oven to work?
  • The imaginative work seems logical in retrospect, though the theory for the effect -- re-partitioning energy between heat and visible light -- remains unexplained. "It's not theoretically predicted," says Fleming. "Possible explanations may involve variations in the speed of light as it propagates through such structures."

    The work was performed with a photonic crystal operating in the mid-infrared range, but no theoretical or practical difficulties are known to exist to downsizing the structure into the visible light range.

    So, they don't have any theory to explain this, but "theoretically" there won't be any problem turning this into something useful. Yeah, sure.

  • Or you could just buy a flourescent (Score:2, Insightful)

    by Anonymous Coward
    Here now, 600% more efficient than normal bulbs and also getting very cheap. They also switch on more gradually, making them less painful on the eyes.
    • They last longer too. Just had one fail, for the first time in 5 years. It was a bit of a shock, I can tell you. I'd forgotten all about buying replacement bulbs.

      • Comment removed based on user account deletion
        • Um, and you're saying that incandescents don't?

          I've replaced all my regular bulbs with fluorescent bulbs and there's no perceptible flicker. They have little bits of electronics in the base of the bulb which stops them flickering.

          Go read: http://www.fujilite.com/product-features.htm

        • The little incandescent replacement bulbs that are flourescents have no visible flicker whatsoever (I presume they have copious amounts of a phosphor like material on the inside equalizing between pulses), and their light spectrum, albeit a little less red, is much purer white than an incandescent. I've nothing but good things to say about them, and like the other poster I've replaced only one in a long, long time. Now that you can get them at places like IKEA for just a small price premium over incandescents, they're a no-brainer (well, unless this technology described in this article comes to the consumer level, as this describes an end result that is far more efficient than even incandescents).
      • But a lot of people (myself included) find flourscent lights too harsh. They tend to emmit a lot of longer wavelength (blue) light. There's nothing like the yellowish glow of an incandescent light bulb. Oh, and they're somewhat smaller - I often end up repositioning table lamps when I'm doing some fine work, but flourescent tubes are more clunky.
        • Blue's shorter wavelength.

          Older fluorescent technologies maybe but the current crop of products in the shops come in different colours and shades of light.

          Phillips for instance do a fluorescent bulb which they describe as warm white is the same shape and is only fractionally bigger than a normal bulb. Fits in a standard socket and lasts for, well, 5 years in my case.

          The bulbs are still more expensive than normal ones but you save in buying replacements and in electricity costs.

    • I did this (put flourescent lamps in a few rooms), and after a few years of experience, I have one main observation:

      The light from flourescent lamps sucks.

      What's ended up happening is that I use the lamps with "normal" bulbs more than the flourescent ones, because the light just annoys me less. I understand that the fluorescent ones are more efficient. That's why I bought the lamps in the first place. The light that they emit, though, is harsh, cold, brittle and annoying. So I find myself avoiding them.

      Given that the electricity difference in my monthly bill in negligable, I choose comfort. Until that equation changes, I don't think fluorescent bulbs are going anywhere.

    • Here now, 600% more efficient than normal bulbs and also getting very cheap. They also switch on more gradually, making them less painful on the eyes.

      If this works, then the new incandescents will be 1200% more efficient than normal incandescents. But the article says 60%, you say? It also says that current tungsten filament bulbs work at about 5% efficiency. Thus, .6/.05=12, or 1200%. (Implying, of course, that the efficient flourescent bulbs you refer to are 30% efficient.) I'd like to note, though, that white LED bulbs are also very efficient, and the 144 LED Medium Base Floodlight Bulb listed here [theledlight.com], for example, is (assuming 5% efficiency for its incandescent cousing) 62.5% efficient, or twice as good as its flourescent cousin. It takes only 12 Watts to generate the same as a 150 watt tungsten incandescent.

      • I'd like to note, though, that white LED bulbs are also very efficient, and the 144 LED Medium Base Floodlight Bulb listed here... takes only 12 Watts to generate the same as a 150 watt tungsten incandescent.

        And for the low, low price of... $698.00. I'd rather spend $18 on a 24 watt fluorescent which will be just as bright. It would take a long, long time for it to use enough electricity to have made the LED bulb a better deal.
  • it's all very nice to create a light bulb that's more energy efficient, but how much more does it cost to create? I understand it's proof of concept at the moment, but it's kind of like those ultra fuel efficient cars; great, you save petrol costs, but you'd need to keep the car for ten years to save enough in petrol to cover the difference in cost between it and a normal car.

    -- james
    • Give the idea to General Electric. Given their experience with lighting systems, they could probably make the new lightbulb design economically practical in a few years.

      Imagine the efficiency of flourescent lightbulbs without the initial high cost--a lot of people would love to buy such a lightbulb.

      • Re:one but... (Score:3, Interesting)

        by ergo98 ( 9391 )
        Much more profound though is that they're basically talking about a device that converts heat into light: The ramifications and applications of that are wide ranging and staggering. Getting even more "goofy", could you have a heat->light conversion, followed by a light->electricity conversion? (i.e. a small "heat energy recovery system").
        • Much more profound though is that they're basically talking about a device that converts heat into light: The ramifications and applications of that are wide ranging and staggering.

          Remember a couple years back when we invented fire? Yeah, that funny little orangish/yellowish glow from the air around the wood, that's kind of the same principle.
        • heat->light->electricity conversion?
          You've got entropy working against you.
          What they're doing is reducing the effects of entropy by something like blocking undesirable radiation from occurring.

  • Yeah .. Tungsten.. (Score:2, Interesting)

    by k98sven ( 324383 )
    The coolest element of them all..

    If you don't belive me read the book "Uncle Tungsten" [barnesandnoble.com].

    Great book, a must for anyone remotly intrested
    in chemistry or the history of chemistry.

    Ok, so it's a shameless plug.. but I just had to push that damn fine book.
  • Take that Law of Conservation!
    • Yeah, I know this is a troll post, and yes i'm relying... buut...

      How does this break the law of conservation of energy? The imput equals the output in terms of energy, just it's done in a manner that produces the desired output energy more efficently,andthus reducing the unwatned energy output.
  • When mine eye falls upon that light
    mine heart turns dark for the unmourned waste
    when in history we once feared night
    and strove to banish it, with undue haste

    that good man Edison born forth the device
    which only made use of one in twenty
    driven by power that which was low in price
    and of that juice there would be plenty

    now science improves upon that thought
    with a tungsten lattice that uses three in five
    hidden with answers we long have sought
    was the mythic efficiency for which we strive

    And nothing remains of that electricity hog
    Save twenty-two billion metric tonnes of smog

  • The real stuff: Nature article (Score:3, Interesting)

    by nniillss ( 577580 ) on Sunday May 05, 2002 @08:46AM (#3465250)
    http://www.nature.com/cgi-taf/DynaPage.taf?file=/n ature/journal/v417/n6884/abs/417052a_fs.html All-metallic three-dimensional photonic crystals with a large infrared bandgap

    Three-dimensional (3D) metallic crystals are promising photonic bandgap structures: they can possess a large bandgap, new electromagnetic phenomena can be explored , and high-temperature (above 1,000 C) applications may be possible. However, investigation of their photonic bandgap properties is challenging, especially in the infrared and visible spectrum, as metals are dispersive and absorbing in these regions. Studies of metallic photonic crystals have therefore mainly concentrated on microwave and millimetre wavelengths. Difficulties in fabricating 3D metallic crystals present another challenge, although emerging techniques such as self-assembly may help to resolve these problems. Here we report measurements and simulations of a 3D tungsten crystal that has a large photonic bandgap at infrared wavelengths (from about 8 to 20 m). A very strong attenuation exists in the bandgap, 30 dB per unit cell at 12 m. These structures also possess other interesting optical properties; a sharp absorption peak is present at the photonic band edge, and a surprisingly large transmission is observed in the allowed band, below 6 m. We propose that these 3D metallic photonic crystals can be used to integrate various photonic transport phenomena, allowing applications in thermophotovoltaics and blackbody emission.

    Doesn't this look like some explanation: the material (unlike metals) has a bandgap, i.e., is insulating and cannot absorb or emit radiation at low frequencies. So the energy has to be dissipated at higher (visible) frequencies. Apparently the output is higher than naive calculations would predict. So the puzzle is not why the frequency of the emitted light is so high, but why the output is so strong for a given temperature.

  • Because I sure did.
    To avoid having this fall into the hands of Westinghouse or GE, do not create a company and go public.

    ...or get an identifiable tatoo on your ass.

    It's the only way to save the world.

  • My obligatory haiku... (Score:3, Interesting)

    by NoMoreNicksLeft ( 516230 ) <john.oylerNO@SPAMcomcast.net> on Sunday May 05, 2002 @08:59AM (#3465269) Journal
    light bulb wastes power
    tungsten evaporating:
    produce more photons!
  • I've always been amused by the observation that in cold climates, incandescent light bulbs approach 100% efficiency, since the heat is desirable.
    • True, but sooner or later, all the light even from one of these new bulbs turns into heat -- except for that light which escapes out the windows.

  • Think of the children... (Score:5, Funny)

    by weave ( 48069 ) on Sunday May 05, 2002 @09:09AM (#3465286) Journal
    It works by "converting waste heat into visible light?" This is going to ruin all of those Easy Bake Ovens.

    And what about when my daughter finds a birds nest that has fallen out of a tree and we need to fabricate a incubator out of a box and a 25 watt light bulb to keep it warm?

    This is horrible news. Think of the children. Call your congressman and ban this insanity.

    • It works by "converting waste heat into visible light?" This is going to ruin all of those Easy Bake Ovens.

      It's going to ruin your lava lamp, too, it'd have to be blindingly bright to get the lava going properly.

      --
      Benjamin Coates
      • I still think that a "Lava Tank" overclocked CPU cooler would be nifty, but I haven't found any lava recipes yet that wouldn't harm the CPU board.

        If only we could clock motherboards up into the frequency of visible light. Then we could use Rack Lighting for illumination from the stray "RF". (Does it worry anyone else that we're starting to clock motherboards up into microwave frequencies?)

    • Well, I know you were joking, but assuming the box is sealed to light, a 60 watt bulb will still put off 60 watts of heat, no matter if it has 100% efficiency or 0%, since the light energy will eventually be absorbed by the sides of the box and turned into heat anyway.
      • but assuming the box is sealed to light, a 60 watt bulb will still put off 60 watts of heat

        The thing is, no one will be buying 60 watt bulbs anymore, since 10 watt new bulbs will put out the same light. Actually, I seriously doubt that old-style bulbs would disappear any time soon - there'll always be a lava lamp and easy-bake oven market for them.

  • Comment removed (Score:4, Interesting)

    by account_deleted ( 4530225 ) on Sunday May 05, 2002 @09:15AM (#3465300)
    Comment removed based on user account deletion
    • Now all they have to do is combining that technology with CPUs. Cool running processors that light up your computer from inside! Sombody call Apple ;-)
    • Since converting to compact flourescent bulbs at home over the past three years, I've often wondered why projectors still use incandescant bulbs. I certainly won't be buying a projector for home use until the problem of cooling is solved. Having brought a few projectors home to try, I've found that the noise from cooling fans outweighs the benefit of the big screen.

      Cool stuff. Literally. :-)

      • Projector Bulbs (Score:2, Insightful)

        by aaarrrgggh ( 9205 )
        The reason we use incandescent lamps for projectors is that you need a point source to be able to focus the image. A flourescent source is too large (a 13W biax lamp would need to be 60" away from a projector to focus the image!), but metal halide lamps work well for high wattages.

        What is amazing is that this is about 3x more efficient than flourescent or High Intensity Discharge lamps! That doesn't quite sound possible... but that is what they are saying!
      • In addition to the fact that a projector needs a point source, a fluorescent lamp also wouldn't have the right color spectrum to make the projected image look right. Although I suppose that could be adjusted for to some degree.
  • Does anyone understand article far enough to tell if this can be used for example to convert some light from one wavelength to other, and increase solar cell efficiency?
    AFAIK, solar cells only use some wavelengths efficiently, other are wasted.
  • Since I can't find it, perhaps somebody from this specific field can answer these questions:

    What part of our total electricity production is going into creating light?

    What part of creating light is done with conventional light bulbs?

    Are the energy savings of this new type of lamp higher than with current 'green' light-bulbs?

    What would the cost offset be compared to conventional lighting? The only thing mentioned is it will be cheap due to the fact that silicon technology production is cheap. How cheap is that compared to conventional light-bulb production? Can't be cheaper.

    Does it cost more in waste-processing?

    Only if we answer all of these we'll know if this will be cheaper for the total product-life-cycle.

    ---

  • Light emitting technology (Score:5, Interesting)

    by wowbagger ( 69688 ) on Sunday May 05, 2002 @10:07AM (#3465404) Homepage Journal
    The science of turning electric power into light has really changed in the past decade. I've seen a graph in one of my engineering trade journals showing the efficency of LEDs in lumens per watt. Just a decade ago, the best LEDs were two orders of magnitude less efficent than flourescent bulbs. Now, the new generation of blue and white LEDs are more efficent than flourescent, and are approching the levels of low pressure sodium lights.

    If we extrapolate from the given 5%->60% levels given in the article, that would raise incandescent lights to nearly the levels of flourescent, without the warm-up time flourescent has.

    Now, the problem with LED vs. flourescent is cost - LEDs are much more expensive in terms of lumens per doller than flourescent. Would microstructured tungsten be any cheaper?

  • Night vision (Score:3, Insightful)

    by GigsVT ( 208848 ) on Sunday May 05, 2002 @10:14AM (#3465414) Journal
    This would make for an incredibly cheap and effective night vision system with a small battery and a CCD camera. IR floodlight with 60% efficiency... mmmmmm.

  • The few people who tried flourescent bulbs correctly noted that they can be harsh light. This doesn't have to be the case.

    Economics works against flourescent bulbs... generally you have a choice in sizes, but there aren't any choices in "mood" (soft, tinted, etc).

    The answer of course is reflected light, or otherwise hiding the bulb. Lampshades and light bounced off the ceiling works great. Not to mention, these things *greatly* reduce the air conditioner strain during the summer (I used to live without AC, but New England summers are rather hot now.).

    It's sad that standard incandescent lightbulbs are not efficency-regulated out of existence. You pay LESS for efficent lighting, if you factor in all the increased energy taxes which come about due to pollution.

    • Interestingly enough. Compact Fluorescent bulbs have changed radically in the past few years. These light bulb makers have listened to the complaints of people and have taken steps to correct the problems with the bulbs.

      - The phosphors on the bulbs have been changed so as to put out a soft "warm" white light just like a regular incandescent bulb. (rather than the traditional "cold" bluish light from the long tube fluorescents.)
      - The bulbs been shrunk even futher to fit nearly every type of lamp fixture.
      - The bulbs are started with electronic balasts (instead of the old magnetic kinds). This eliminates "flicker" and allows the bulbs to start instantly rather than taking a few seconds to start.
      - The life of these bulbs is usually around 10,000 hours (exceedingly longer than the measly 750 to 1,500 hours of most incandescents.)
      - Energy Efficiency of most of these bulbs exceeds 75%! (still much better than this "improved" incandescent that this thread is about.)

      A small handful of states subsidize purchase of these bulbs. Check out The Energy Guide [energyguide.com] for great deals on Fluorescent bulbs. I've changed all the incandescents in my house to compact fluorescents, and I've knocked at least $10 / month off my electricity bill!

    • Does anyone know of a CFL that is sized (and shaped) appropriately for the light fixture on a celiing fan? These are just about the only places we have incandescents in our house. A CFL replacement would need to be about half the size of the run-of-the mill CFL, have output roughly equivalent to a 30-40w incandescent, as well as being shaped similarly to a standard bulb due to Wife Acceptance Factor.

  • What about LED's? (Score:4, Interesting)

    by dpbsmith ( 263124 ) on Sunday May 05, 2002 @12:00PM (#3465750) Homepage
    Incandescent lamps... around 20 lumens per watt. Fluorescent lamps... about 70 lumens per watt. White LED, 50 lumens per watt and climbing. And the power requirements and ability to fit them into small spaces are much less tricky than for fluorescent.

    LED's are almost there--and efficiencies are climbing. Main problem right now is that they're expensive. But already, I see they're being used for the red, and, increasingly, the green lights in traffic lights around here.

    By the time this stuff makes it out of the lab, LEDs will be cheap and even more efficient than they are now.

    And, of course, all the gee-whiz wizards-of-the-labs articles never say how much the new technology is likely to COST. And the stated efficiencies tend to decline as the devices start to approach reality...

    If they can really make these things twelve times as efficient as LED's AND give a pleasant, flattering light spectrum AND get the cost down, it will be interesting.
  • The advance also opens the possibility of increased efficiencies in thermal photovoltaic applications (TPV).

    A breakthrough in solar energy ?

    I wonder what the energy density from the sun is in the IR spectrum ?

  • Granted this is on the heels of the bubble fusion article

    But this is superlatively revolutionary. Take the two possible big-hit applications: massive energy efficiencies coupled with a 20-30% increase in photovotalic efficiency (read: reduced cost) and this is a big step toward alternative energy.

    Imagine a mass-produced fuel cells and increased efficiency photovotalics with lighting generated by these things. Who needs a power company?

  • nice, but no solution to energy problem (Score:3, Insightful)

    by j09824 ( 572485 ) on Sunday May 05, 2002 @03:07PM (#3466387)
    This is great work. But if people want high-efficiency, pleasant-looking light-bulbs, they can already get them and save money in the process. The fact that people don't buy them despite all their advantages suggests that the problem isn't technology, it's people.
    • That's true, but they save money in the long run by spending more money up front. Many people don't do this because they think short term, not long term.

      So this technology is a possible solution to the energy problem, but only if it gets sold at roughly the same price point as current lightbulbs. But you can expect that they'll be sold at a premium even if the manufacturing costs are the same, simply because they're better, and so the problem of high energy consumption will remain.

  • Color? (Score:2, Insightful)

    by Shook ( 75517 )
    I wonder what these lights would look like. Some of our more efficient lights (like sodium) have colors nowhere near natural sunlight. There's plenty of niche markets for different lighting sources. Colored LED's for signals, flourescent for efficient indoor lighting, orange/pinkish sodium lights for outdoors.

    I think the color of the light produced would be very important for its potential uses.

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