LED Light Bulbs - why?

[Jeff7]

i'm thinking LED's future isn't in sockets but in the fixtures themselves.

The tricky part will be making a fixture that'll last the life of the LEDs inside - and then handle whatever new technology is coming along. So in 10 years, when those LED lights are finally dimming to the point of needing to be replaced, <new thing> will be available, which only bears a cursory resemblance to LED technology.

 

[keird]

The tricky part will be making a fixture that'll last the life of the LEDs inside - and then handle whatever new technology is coming along. So in 10 years, when those LED lights are finally dimming to the point of needing to be replaced, awesome sauce will be available, which only bears a cursory resemblance to LED technology.

Edit

 

[phucheneh]

Thanks for the explanations, Jeff. I think I'm starting to understand this stuff a little bit better. Also my brain itches.:\

I know Ohm's law and apply it quite often to incandescent bulbs (or LED assemblies), electric motors, ect. Generally simple circuits (relative to EE type stuff, at least).

But when it comes to semiconductors and their associated parts...basically anything on a circuit board with solid state parts...trying to understand the theory can make me go a bit cross-eyed.

 

[Jeff7]

Thanks for the explanations, Jeff. I think I'm starting to understand this stuff a little bit better. Also my brain itches.:\

I know Ohm's law and apply it quite often to incandescent bulbs (or LED assemblies), electric motors, ect. Generally simple circuits (relative to EE type stuff, at least).

But when it comes to semiconductors and their associated parts...basically anything on a circuit board with solid state parts...trying to understand the theory can make me go a bit cross-eyed.

I'm actually rather limited in my electronics knowledge. :\ Pretty good with LEDs though.

I still lack the intuitive ability to create a circuit of discrete components. I can do the fancy (or simple) stuff by programming a PIC. All the boards in old stuff like oscilloscopes from the 70s or older....wow. I just don't know how to begin to design something like that, with getting all those passive and semiconductor parts to work together to do something other than pop and smoke. Stringing together simple ICs...yeah, maybe.

<-- Went to college for mechanical engineering technology. And here I am in a job that has me doing mechanical design, some electronics work, and also PIC programming. I think the "M" in MET is for Miscellaneous.

 

[Rubycon]

Incandescent lamps waste a lot of power.
CFLs contain Hg.
LED lamps contain As.

Not talked about now but in a few years when lots of them start showing up in landfills it could be a big deal. (or will the water tables be screwed up from fracking?)

LEDs are quite sturdy so if one falls on the floor chances are it will still work. Do the same with a CFL, time to break out the broom. (and open windows if you're really worried about a TINY bit of Hg!) When I went to school we played with a drop the size of a pea - in the palm of our hand! It was really eerie if the flask was refrigerated first. Boy was that metal cold!

The future of LED lighting is bright indeed.
Some of the most powerful LED torches actually throw a considerable amount of heat like a tungsten-halogen bulb despite much higher efficacy.

With yet improved efficacy (breaking the 200 L/W barrier) and higher CRI they could replace HMI on the stage. That's very exciting giving all the options one has with controlling LEDs.

 

[SagaLore]

Anybody else notice the refresh flicker from led lights?

 

[Rubycon]

Anybody else notice the refresh flicker from led lights?

Depending on the waveform and frequency it can be quite noticeable. LEDs have very fast attack/decay times unlike incandescent lamps.

I can tell newer buoy markers instantly as the older tungsten lamps will have much longer decay times vs. LED which go instant on to instant off. Traffic signals are the same way.

I suppose a driver could simulate this so it would be nearly impossible to distinguish unless you're really taking the nerd approach with a diffraction grating!

 

[SagaLore]

Incandescent lamps waste a lot of power.
CFLs contain Hg.
LED lamps contain As.

Not talked about now but in a few years when lots of them start showing up in landfills it could be a big deal. (or will the water tables be screwed up from fracking?)

LEDs are quite sturdy so if one falls on the floor chances are it will still work. Do the same with a CFL, time to break out the broom. (and open windows if you're really worried about a TINY bit of Hg!) When I went to school we played with a drop the size of a pea - in the palm of our hand! It was really eerie if the flask was refrigerated first. Boy was that metal cold!

The future of LED lighting is bright indeed.
Some of the most powerful LED torches actually throw a considerable amount of heat like a tungsten-halogen bulb despite much higher efficacy.

With yet improved efficacy (breaking the 200 L/W barrier) and higher CRI they could replace HMI on the stage. That's very exciting giving all the options one has with controlling LEDs.

I think LEDs will become the light of choice for applications like christmas lights or small bulbs, but for main lighting FIPEL will replace it all:

http://phys.org/news/2012-12-goodbye-fluorescent-bulbs-technology-wont.html

:awe:

 

[Rubycon]

I think LEDs will become the light of choice for applications like christmas lights or small bulbs, but for main lighting FIPEL will replace it all:

http://phys.org/news/2012-12-goodbye-fluorescent-bulbs-technology-wont.html

:awe:

For widespread sources it's a contender. Where point source is needed no. It's a very soft source.

For interior rooms it may be good to simulate outside light behind a curtain. Use it as a backlight for an LCD panel and you could even do virtual windows. Of course other display technology is going to make LCD obsolete possibly in the same time period.

 

[Jeff7]

Anybody else notice the refresh flicker from led lights?

Yes.
I didn't think it possible, but I can see it to somewhere around 4000-5000Hz, at which point it really starts to die off. (Checked with an oscilloscope.)
I always liked CRTs that could manage at least 85Hz. 120Hz+ was preferable. The phosphors in a CRT have a much longer decay time than an LED does though. LEDs stop emitting power almost as soon as the power to the die is cut; I think that all you've got is maybe the residual capacitance in the wire to keep the light coming.

I hate the LED taillights in cars and trucks. They've got to be flickering somewhere well south of 1kHz. (Hm...this conversation feels familiar...)

I think LEDs will become the light of choice for applications like christmas lights or small bulbs, but for main lighting FIPEL will replace it all:

http://phys.org/news/2012-12-goodbye-fluorescent-bulbs-technology-wont.html

:awe:

I was thinking of that very article while writing that bit about "<new thing> will be available, which only bears a cursory resemblance to LED technology."
Hopefully it pans out. OLED was meant to be super-awesome for all kinds of reasons. Last I heard about it, they had some serious lumen-maintenance issues with the blue. And if you're trying to make white, and you've got different decay rates with the red, green, and blue emitters, you're either going to have some bad colors in the future, or else you need a sensor that can measure the light coming out, and adjust how hard each color is being driven. Not an easy task on a dynamic source with thousands of individual emitters.

Definitely interesting technology though. Hopefully it won't end up costing $500 per square inch, or per lumen.



And, just some gripes with the article:

The lighting, based on field-induced polymer electroluminescent (FIPEL) technology, also gives off soft, white light &#8211; not the yellowish glint from fluorescents or bluish tinge from LEDs.

"People often complain that fluorescent lights bother their eyes, and the hum from the fluorescent tubes irritates anyone sitting at a desk underneath them," said David Carroll, the scientist leading the development of this technology at Wake Forest. "The new lights we have created can cure both of those problems and more."

These problems are already solved.
- Use LEDs that aren't up in the 6000K and beyond range. Or use ones that are actually made for lighting. Though some of the "illumination grade" LEDs still have low CRIs. They're also sometimes trying to compete with sodium vapor lamps, which are insanely efficient, but also effectively lack a CRI rating, as they are monochromatic light sources.
- Use electronic ballasts, which shouldn't ever hum, unless your ears can hear well above normal human hearing, or if the manufacturer is cheaping out and using very cheap drivers; then you'll get some high-frequency inductor whine.
- Get good fluorescent tubes. They're also available in the 2700K-3000K area, mimicking incandescent light sources. But, once again, quality usually demands more money.

 

[BUTCH1]

Incandescent lamps waste a lot of power.
CFLs contain Hg.
LED lamps contain As.

Not talked about now but in a few years when lots of them start showing up in landfills it could be a big deal. (or will the water tables be screwed up from fracking?)

LEDs are quite sturdy so if one falls on the floor chances are it will still work. Do the same with a CFL, time to break out the broom. (and open windows if you're really worried about a TINY bit of Hg!) When I went to school we played with a drop the size of a pea - in the palm of our hand! It was really eerie if the flask was refrigerated first. Boy was that metal cold!

The future of LED lighting is bright indeed.
Some of the most powerful LED torches actually throw a considerable amount of heat like a tungsten-halogen bulb despite much higher efficacy.

With yet improved efficacy (breaking the 200 L/W barrier) and higher CRI they could replace HMI on the stage. That's very exciting giving all the options one has with controlling LEDs.

And the LED will give it's full brightness very quickly and the same for shutdown, I could imagine some awesome sequential light shows would be possible..

 

[Jeff7]

And the LED will give it's full brightness very quickly and the same for shutdown, I could imagine some awesome sequential light shows would be possible..

Ironically, the LED source should give full brightness instantly, but then decrease as the emitters warm up.

The good news is that white LEDs aren't too severely affected by this.
It's the red and amber dies that can go way down, maybe to 50% of their cold brightness, depending on how hot they're permitted to get.
Sometimes, I think physics just likes to troll us.

 

[Rubycon]

Ironically, the LED source should give full brightness instantly, but then decrease as the emitters warm up.

The good news is that white LEDs aren't too severely affected by this.
It's the red and amber dies that can go way down, maybe to 50% of their cold brightness, depending on how hot they're permitted to get.
Sometimes, I think physics just likes to troll us.

If the design isn't focused on excessively overdriving emitters this foldback isn't in the perceptible range.

 

[wirednuts]

led tech is not in its infancy, but it has tremendous room to grow. especially in efficiency...

 

[DCal430]

LED just are not cost effective, their is no point in getting a $30 to $50 LED when you can get a 15 to 25 cent CFL, you can replace this CFL over and over again and still it will be cheaper in the long run.

The best LED will only save you about $5-$6 a year compared to a CFL and this includes the cost of replacing the CFL, it just isn't worth it.

 

[Chris A]

I have a led surefire flashlight that is a light cannon!

 

[BladeVenom]

led tech is not in its infancy, but it has tremendous room to grow. especially in efficiency...

Red ones are ancient, but blue and white are newer.

 

[SagaLore]

LED just are not cost effective, their is no point in getting a $30 to $50 LED when you can get a 15 to 25 cent CFL, you can replace this CFL over and over again and still it will be cheaper in the long run.

The best LED will only save you about $5-$6 a year compared to a CFL and this includes the cost of replacing the CFL, it just isn't worth it.

It would be cost effective if it weren't for-profit companies producing them. They have a huge markup to compensate for the drop in revenue from frequently replaced bulbs.

 

[Imp]

It would be cost effective if it weren't for-profit companies producing them. They have a huge markup to compensate for the drop in revenue from frequently replaced bulbs.

You really have to wonder how a company prices a bulb that's supposed to last 20 years.

CFLs should at least break every once in a while, if they don't burn out randomly. From what I've seen, LEDs are encased in plastic (?), so aside from not burning out, they don't randomly break.

 

[evident]

i'm ready to take the plunge and buy some LED lightbulbs for some annoying R16 sized light fixtures i have in my bar and kitchen area. the incandescents i buy burn out every 6 months and they cost $5 a pop. the LED's are about $35 a pop however.

 

[RossMAN]

i'm ready to take the plunge and buy some LED lightbulbs for some annoying R16 sized light fixtures i have in my bar and kitchen area. the incandescents i buy burn out every 6 months and they cost $5 a pop. the LED's are about $35 a pop however.

Depending on the wattage/brightness you're looking for, here's a good model for around $25 .
http://www.homedepot.com/h_d1/N-5yc...=-1&keyword=888865&storeId=10051#.UNqQ_G_AeSo

After reading rave reviews of the Philips LED, I bought one and it's exceeded my expectations. I wish it was a little brighter and cheaper. When these hit $8 - $10 I'll buy a dozen or two to replace every bulb in the house.

If you have access to a CostCo they have an LED bulb on sale for around $10 after instant rebate, I'll post more details later when I have the specs and SKU #.

 

[SparkyJJO]

I thought I was sensitive to light flicker (CRT monitor must be 85Hz+ or it bugs the crap out of me) but I almost never see car LED lights flicker at all. Some of those cheap aftermarket ones do at lower intensity as they use PWM to "dim" the light vs a linear reduction of current/voltage to achieve the desired result.

I have a couple el cheapo LED bulbs I bought off ebay middle of 2011 simply out of curiosity (They were only $6 each I kid you not). They look the part of cheap junk too, but surprisingly despite not really being heatsinked well (none even visible) and the heat causing the boards to discolor a bit and the clear lens fog up some they still work flawlessly and without flicker. Not the brightest things but the one in the bedroom ceiling light actually lights up the room decently well.

I still greatly prefer incandescent lighting over all other forms as far as light quality goes however.

 

[William Gaatjes]

So, I've been stalking Ikea's website and just came back from a visit to the store, and noticed that they have some relatively cheap LED light bulbs. I've seen some at Wal-Mart and Costco too in the past few years, but those were $30 and up -- the Wal-mart one was a huge one with a few dozen LEDs on it.

http://www.ikea.com/us/en/catalog/products/40222476/

The one above is from Ikea for "only" $13. But it's rated at 400 lumens and 8.5 watts.

The 7W CFL I use as a backlight is something like 385 lumens (around a 40W incand.). Other common 40W-equivalent CFLs range from 7W to 10W.

Is LED tech still very early in its infancy, or is this as good as it gets?


Edit:

Okay, 12.5W = 60W LED from Phillips. Only $30...

http://www.homedepot.ca/product/125w-led-a-dimmable-soft-white/926038

Edit2: removed "suck"

Here is a few handy tips.
For the not dimmable lights, i have taken a practical approach. Instead of buying one 10 watt led lamp that is very expensive, i search for lamp armatures that can hold at least 3 led lamps. Then i just buy the 1.2 watt price discount led lamps. and together these lamps can provide enough light to satisfy my requirements. Because of the low wattage, these lamps do not get hot or breakdown as easily as the higher wattage led lamps.

When it comes to dimmable led lights, make sure you have a trailing edge dimmer. Because of the smps (switching mode power supply) integrated into the led lamp, these led lamps work better with trailing edge dimmers. Because then the inrush current at every start of the net period increases gradually instead of instantly to a maximum as will happen with leading edge dimmers. This is because of the capacitors in the led smps.

Leading edge dimmer.

Trailing edge dimmer.

As an electrical engineer/technician and hobbyist, i am in the process of designing my own dimmer that can be set to trailing edge or leading edge. The plan is that it can be controlled by uart (electrically isolated) and also wireless when needed.

I already got the whole high voltage section figured out (2x 600V mosfets in anti serial configuration with a special self powered electrically isolated gate drive circuit). Now all i need to do is to build the prototype.

A website about the differences of dimmers.
http://sound.westhost.com/lamps/dimmers.html

P.S.
When i got it working, i will post a pdf schematic. I will make a drawing and post it in highly technical when ready.

 

[Squisher]

LED just are not cost effective, their is no point in getting a $30 to $50 LED when you can get a 15 to 25 cent CFL, you can replace this CFL over and over again and still it will be cheaper in the long run.

The best LED will only save you about $5-$6 a year compared to a CFL and this includes the cost of replacing the CFL, it just isn't worth it.

But, IF you can use the 12.5w (75 watt eq.) from HD for $15 then your payback is only 3 years and you can dim them so much better.

 

[SandEagle]

The Light Bulb Conspiracy
Planned Obsolescence

http://news.consumerreports.org/hom...b-conspiracy-probes-planned-obsolescence.html

http://conspiracy.wikia.com/wiki/Light_bulb_conspiracy