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Light Bulb Technology?

Discussion in 'LEDs and Optoelectronics' started by dan howitt, Jan 6, 2016.

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  1. dan howitt

    dan howitt

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    Jan 6, 2016
    Where do you think light bulb technology will go in the future, best, Dan Howitt.
     
  2. Osmium

    Osmium

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    Jan 28, 2013
    "Internet of Things" connectivity eg: Philips 'Hue'. Controlling mood, scenes, reactivity via connected apps.
     
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  3. Harald Kapp

    Harald Kapp Moderator Moderator

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    We'll probably see less light bulbs in the future. LEDs allow for so much more flexibility in designing lighting fixtures and will (hopefully) outlast the lifetime of the fixture. Therefore no need to replace "bulbs"
     
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  4. Bluejets

    Bluejets

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    Light bulbs as we know them have all but been taken off the shelves in Aus.(Government requirement)

    In my experience, LED's in the home aren't worth a cracker.
    We've replaced maybe 20% of the one's we've installed, mainly the drivers break down and the cost of the driver (if one is available) is almost as much as the complete fitting.
    Granted, no more replacing bulbs, just the complete fitting. now instead of $1.00 bulb, $20.00 fitting plus a service call.
     
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  5. Harald Kapp

    Harald Kapp Moderator Moderator

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    I've made similar experiences with cheap LED light bulb replacements.
    Since I shifted to a bit more expensive brand LED "bulbs", however, I'm happy and I've had no more failures since (2 years+).
     
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  6. Osmium

    Osmium

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    I replaced 2 4' twin fluorescents with equivalent led tubes. They are brighter, instant on, very pleasant light. 12 months now. Very happy. The remainder of the lights through the house are slowly being converted - no issues so far.
     
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  7. BobK

    BobK

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    I have LED bulbs and fluorescent replacements pretty much everywhere in my home, starting 5 years ago or more. I have had one failure, when the glass part of the bulb actually fell out! All others are still working and I am very satisfied. I have used multiple brands, CREE, Phillips, Feit, Utilitech (cheap store brand) and all seem to be reliable for me.

    On the other hand, compact fluorescents seem to have a 50% failure rating in 2 months for me, though, if they don't fail in that time, they seem to last.

    Anyway, in answer to your question. I think LEDs will definitely predominate in the near future.

    Bob
     
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  8. Bluejets

    Bluejets

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    The final comparisons are how much does it cost to convert, how much do you save in comparison.
    How long does the new fitting last in comparison to the old, not what the manufacturer claims but actual time.
     
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  9. Osmium

    Osmium

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  10. Gregorio Mandigma

    Gregorio Mandigma

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    Jan 2, 2016
    Light bulb is more accurate when it synchronized to blink of an eye. most likely a smart light. a infrared bulb light up your face to help the eye sensor to catch your act
     
  11. BobK

    BobK

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    Interesting idea. Blink the light off when we are blinking. Doesn't work well with 2 or more people in the room, though.

    Bob
     
  12. JoeM

    JoeM

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    I replaced all of my regular light bulbs with LED bulbs that I bought for anywhere from $2.40 each, up to $3.00. You might think that the only savings is in the energy used, but nothing could be further from the truth. Living in Florida, we have more hot, and hotter days than many other states, so Air Conditioning is used for 80% of the year, and 24/7. If the three 60 watt incandescent bulbs in a ceiling fan are on for more than 30 seconds, they heat to the point that you can't touch them without burning yourself badly. The LED bulbs run cool, and they can be held with a burn, and they do not cause my Air Conditioner to run extra to remove the heat that their predecessor did. So the savings adds up fast than many think.
    LED bulbs are here to stay, they will not pollute our planet as much as compact fluorescents do, and LED's run way cooler also run cooler than any of those. What will change is the cost, and quality of LED bulbs, and possibly the range of types that are commonly available.

    I've already seen shop lights, flood lights, soldering gun bulbs, car lights, christmas lights, and many others that are now produced with LED technology.

    What is slowly going away are the LED bulbs that run hot do to poor electronic drivers in their base. That is just one of the technology improvements, the other is more efficient LED's with mush better light being produced.

    I like the warm lights for common household lamps, and bedside lamps, and nobody can tell the difference until they touch it. The cool LED's worked well in the bathroom ceiling fixtures that use to have hot holligen bulbs. I get plenty of light, and no heat.

    If anyone has any LED's that have failed, and or exploded, well that is simply supply and demand making the Chinese try and cash in before the supply,ands price catches up with the demand. The demand is there, but there are many people that look at a $2.50 light bulb and think they would have to be crazy to pay that for a light bulb when they can go to the dollar store and by 4 incandescent bulbs for $1, or less.

    The good news is that those bulbs will be gone soon, per our governments restriction on selling them

    For LED's to go away, we would have to have a new technology that would not pollute our earth, and be better at producing light, and be cheaper. Fat chance that will happen anytime soon.

    The worst problem we face right now, and is only getting worse, is water. If you doubt that, then you don't know enough.
     
  13. Bluejets

    Bluejets

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    Photo is of one of the latest trends in downlights. Mostly around 10W.
    If no heat dissipated as you claim, then why the rather large heatsink?
    Not the LED...mmm how about the driver.
     

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  14. JoeM

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    Ok, did I say no heat? What I should have said is low heat, relative to the same light output of an incandescent, fluorescent, or halogen bulb. My 60 watt LED bulbs draw 8.5 watts of power, and generate a fraction of the heat of a standard incandescent bulb of 60 watts. I didn't need to read the package to know how little heat they generate, the three bulbs in the ceiling fan in my Radio room would cook me before I went o LED. I would leav the light off rather than use it, and now I keep it on more than not.

    I also don't claim that every manufacture strives for low heat.
     
    Last edited by a moderator: Feb 17, 2016
  15. daberbaber

    daberbaber

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    Heat is energy wasted to be sure and like it's been pointed out, that heat has to be removed via AC in warmer/hot climates. The LED is a forward voltage turn-on device and unless placed across each other reversed, no current is drawn on an AC main in one direction so there will be a flicker noticeable when one scans their eyes across a device - light, readout, etc.- quickly. Even in the back to back connection there is an off time due to the forward conductance. Incandescents didn't have that effect because their heated filament had a latency that still emitted photons during the cross over. Now it you rectify the AC to DC there will be no off time since conductance is always happening as long as the voltage was higher than the turn-on voltage...even Pulse Width Modulation used for dimming normally has some latency of photon emission because the PWM duty cycle is occurring at a higher frequency than the eye can perceive which is about 30 cycles per second if I'm remembering correctly. What I would like to see is the trend to be placing LEDs in series so that the cumulative voltage drop is closer to the RMS value of the AC. I built a Christmas tree LED strand back in the 1970 with samples I received as an engineer/salesman using Green, Red, & Yellow LEDs and it is still functioning even though I've left it on during the years for years at a time...probably been on over 50% of the time. It's only working in the half wave rectification mode and has a small low wattage resistor to limit the current to around 30mA and that's through the whole strand/each LED. The other option is to have a separate lighting voltage rail available to DRIVE only LED lighting devices...low DC or AC so that 120 VAC that peaks at around 160 VAC each direction doesn't have to be dropped at each device because that wastes a lot of energy hence heat buildup AND it adds a lot of electronics/drivers that have higher failure rates than the LEDs themselves. CF bulbs have that same problem since EVERY bulb has its own electronic ballast built into the base...those are what normally fail during the "burn-in" period and I've seen that same failure rate discussed above. Once the CF bulb has run for a few months, it seems to run to its expected life spam as long as it isn't turned on and off excessively/power cycled.
    So I guess what I foresee is a separate power rail to drive our lighting devices or building the driver right on the LED chip but that has its own set of problems due to the semiconductor material used for the LEDs and the driver being made out of different elements currently.
     
  16. JoeM

    JoeM

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    My thoughts are made by observation only, and then common sense. The CF bulbs get as hot a fire, and would cause severe burns if they are removed with a bare hand after being left on for a short period. The same can be said for the incandescent bulbs. Take a 60 watt incandescent and iy will cause the same sort of burns that the CF caused. The LED bulbs, not only don't get nearly as hot, but the 60 watt bulbs draws 8.5 watts. You can draw whatever conclusions you like about what they do with that 8.5 watts of power, but it clearly is only 8.5 watts for 850 lumens.. The cheaper bulbs draw 9 watts, and put out less light, but it stills beats all other choices for lighting. It is also true that the heat from three 60 watt incandescent bulbs in the ceiling fan over my head were very uncomfortable in terms of how hot the room got, and that made me keep them off unless I really needed them. The LED bulbs do not heat the room anywhere near from CF, or incandescent do. None of the LED bulbs I am using produce any flicker that I can perceive, and I defy anyone to tell me they can say which lights are LED and which are not in my home. As it is now, most are LED, and what is not LED is because the type of bulbs I would have to replace are odd, and LED bulbs to replace them would be very expensive for now.
     
  17. ChosunOne

    ChosunOne

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    I thought I'd bring Osmium's post #9 back up because it appeared that everybody, so far, who posted after him/her either didn't bother to follow the link, or ignored it. This is recent new in the field of electrical lighting and to me it looks plausible that incandescent lights are still in the running if scientists at MIT can pull this off. From this one article, it looks promising. And it's definitely relevant to the OP's question.


    I also have switched out all lights in my home to CFs and LED (but no cheap Chinese junk) a couple of years ago with only a couple of CF failures so far. But let's be fair: Florida USA and similar climates notwithstanding, there is a significant amount of the year in more northern climates where incandescent bulbs run at 100% efficiency--because the heat from them isn't _waste_ heat, Granted, there are more practical (cost-effective) means to heat enclosures in most cases, but it isn't "waste" when it's providing something that's needed and used.

    As long as I'm picking nits--we're technical people on here. Can we stop referring to a bulb's light as "nn Watts of light" and call it by what it is? Namely, "lumens"? Light isn't measured in Watts. Which is why the various bulb packaging displays the lumens specification nowadays.
     
  18. JoeM

    JoeM

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    What the article does not say, is how much heat the bulbs generate. Inferred, if it emits from the light, will heat whatever it hits. They are not close to their goal, and the data on what they did do was not complete in the article, so it is hard to predict its effect on the future of lightbulb technology.

    Even the efficiency of the LED bulb varies from one manufacturer to the next. So the assumption is that the more efficient bulbs cost more to make than the less efficient.

    So the data from MIT is a pipe dream as of now. If they had reached 50% of their goal, I would say that is promising. They said nothing about the cost, and the difficulty that might face mass production. So the likelihood is that LED technology will get better long before they figure out how to make the glass incandescent bulb better and cheaper than an LED.

    Lastly, what made a group of smart people spend so much time on keeping the incandescent bulb alive, instead of finding ways to improve the LED, or finding an alternate source of efficient lighting?

    You are right, in cold climates the heat from a bulb is not wasted, but it is wasted energy when you consider that there are cheaper ways to keep warm. It is a fact that most people spend more on making cheaper heat, than they do on making their home more efficient at keeping more of what they make.

    I don't claim to be smarter than any of you, but I do understand the technology, and it allows me to use common sense to come to my conclusions.
     
  19. Osmium

    Osmium

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    Jan 28, 2013
    It's not so much "keeping the incandescent bulb alive", Joe. Those smart people asked a question something like "Is it possible to re-direct radiated energy using nano-technology so that 'unwanted' energy can be re-used to make desired radiated energy?". The incandescent bulb is a convenient focus for the research but the application of the acquired knowledge is far broader. The proof of concept experiment was highly successful showing that the technology, the idea, could indeed work. Now it's about understanding the detail - how you make the re-direction and re-use of the energy more efficient.
     
  20. daberbaber

    daberbaber

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    Feb 2, 2012
    I believe that the LED has a "brighter" future than re-inventing a heated filament technology since the energy there is emitted over a very wide range and inherently inefficient. Back to the white LED and flickering when used with an AC supply - the "white" LED was developed from the blue/UV spectrum diode as I recall and by adding a phosphor as is done with fluorescent tubes, a persistent emission can occur which cuts down on the flickering when observed with our eyes that also have a scan rate below the persistence decay...that's not to be meant as too technical since that flickering problem became evident even with FTubes. But what I'm trying to relate is that our AC distribution system is a main concern when we hook direct current DC LEDs up to it. As I mentioned earlier, a back to back reverse polarity arrangement provides for a 100% on time except for a very small portion when the diodes are not conducting. It would seem to me that if the AC supply voltage is dropped to match the conductance voltage, a device becomes more efficient than operating it off full 120 VAC...ie, matching the supply closer to the forward conductance voltage. The same could be done by placing more diodes in series like I did with my Christmas light strand but that results in a higher probability of failure due to more interconnects. An approach where the LEDs are diffused directly onto the chip substrate for this purpose seems more likely than any other approach. It would be similar to when the transistor was a discrete device and Norris? made it into an IC now having millions of transistors on one substrate/chip. The FET field effect transistor technology has improved to the point where it now handles hundreds of volts and switches at a high efficiency that reduces the waste heat. Somehow the LED GaAs and the IC silicon technologies have to be layered so that the benefits of both allow us to make more efficient, more reliable, and hence cheaper mass produceable LEDs in the future which is where this topic wants to go I think.
     
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