Let there be (blue LED) light

[EJ]

Re: Let there be (blue LED) light

The vacuum tube analogy is a good one; in fact with solid state lighting, spectral digital control is now a reality. There's been a lot of research over the past decades on artificial lighting's impact on health, e.g., sleep disturbance and circadian rhythm disruption, increased cancer rates amongst late night shift workers, etc; A lighting system that can change it's spectrum based on time/location/personal schedules to optimize circadian rhythm (or minimize disruption) and thereby aid in health, productivity and performance (pro athletes use lighting to both mitigate the effects of jet lag and night game handicap).
We'll see smartphone's and tablets with biologically correct displays before long (they are already doing it with filtering but it is energy inefficient for a battery dependent device; a new backlight architecture is needed).
The efficiencies are just starting to exceed that of CFLs - and you can dim; we are still in the early stages of adoption and energy rebates are still a big part of the value proposition to consumers

Four years ago when I lectured the Public Power Association on the topic they were not happy about the prospect of LEDs significantly reducing electricity demand. They wanted me to say that reams of Teslas were to take up the slack but I could not offer that assurance.

[santafe2]

Re: Let there be (blue LED) light

Back in 2008...I interviewed the founding CEO of Luminus Devices Udi Meirav...he lamented that...50 years later we are still using vacuum tubes for lighting.

Six years later this idea is becoming fact, with warm white light LEDs rapidly coming down in price.

I am still surprised at how rapidly the modern world can adapt to changing needs. I still shake my head regarding the US shale oil boom. It happened almost overnight and without it there would be no oil "glut". Six years ago, LEDs were only for very early adopters. Electric cars were owned by hobbyists. The iPhone had been out a year, luxury. Social networking finally went large with Facebook. From now on, as long as we don't break the system, every decade will be the most innovative decade. Careful Luddites, it's not going to be easy to watch.

[santafe2]

Re: Let there be (blue LED) light

In the meantime with "non-smart" LED's falling in price fast, along with increasing availability of better warm white output, it is causing me to permanently displace more and more incandescent bulbs in the bunker with LEDs.

Yup, the now very well insulated dirt home has mostly LEDs and it saves enough energy to power about 1/3 of the Chevy Volt energy requirement. My wife has banished all the CFLs and I've had to admit I was wrong, (completely, utterly and totally wrong), to require that we switch much of our lighting away from incandescent in 2005. BTW, not one of those awful lights ever made it's way into the kitchen...regular Maginot Line of lighting.

[astonas]

Re: Let there be (blue LED) light

Agree on the first point. However, the first LEDs that were available locally were an equally harsh bright white light, worse than a halogen. Only recently are we starting to see some spectral variety here. The Canadian market is much smaller than the USA, so often our selection is limited or it takes longer for new products to appear up here.

No, you're right in your observation, and not just locally. It's still slow coming from production. (At least, slower than the industry wants it to be.)

The problem is the phosphors that convert the single-wavelength LED emission to a broader spectrum. Organic materials are readily available, but have lifetime challenges. Quantum dots are being worked on, but aren't quite there yet. But while the latter have more engineering - and slightly fewer fundamental physics - limitations, neither is perfect. I'd expect that QDs, and perhaps eventually something even better, will be in lighting products relatively soon. (They've been in LED-illuminated LCD displays for a couple years.)

Until then, however, be aware that the promise of extraordinary lifetimes may be accurate when it comes to the bulb still emitting light, but not necessarily a guarantee that the spectrum will have the same shape as the day you bought it.

[jpatter666]

Re: Let there be (blue LED) light

Yup, the now very well insulated dirt home has mostly LEDs and it saves enough energy to power about 1/3 of the Chevy Volt energy requirement. My wife has banished all the CFLs and I've had to admit I was wrong, (completely, utterly and totally wrong), to require that we switch much of our lighting away from incandescent in 2005. BTW, not one of those awful lights ever made it's way into the kitchen...regular Maginot Line of lighting.

We too have a small pile of spare CFLs. Once the LEDs became cheap enough any time a bulb failed I replaced it with LED (excepting in a chandelier -- not quite WAF yet). I buy nothing but CREE -- the ones they sell at Costco are junk. I've never had a CREE bulb fail.

The first thing you notice is the heat reduction -- very noticeable in summer in a bathroom.
Second is the cost savings -- I work from home so lights are on all the time. Between LED screens (computer and TV), bulbs and some upgraded appliances my electric bill is *less* than it was a decade ago.
Third is time and effort. I hardly ever change bulbs anymore which means I don't need to keep a box of spares either.

On a final note, so far LEDs work *great* in ceiling fans. The number of incandescent bulbs that got shaken to death in those fans....even ones supposedly built for them.