Do you think...

o0o

Enlightened
Joined
Jun 3, 2007
Messages
340
... LED color rendition can ever match incandescents? Will there be a day when LEDs can render outside settings as well as incandescents?

What technology aspects would need to improve to achieve said goal?
 
It's all about the phosphors and their excitation wavelength. I suspect that as the wavenelgth of the underlying LED gets shorter, it will open the door to new phosphor combinations. Fluorescents and CFLs use shortwave UV for their source, and UV LEDs are still pretty far away from that wavelength so they can't use the phosphor blends currently in use by fluorescents. While there are shortwave UV LEDs, their power output is incredibly small, their cost is incredibly high, and they're really still in the prototype stage. The thing is when you have a shortwaver excitation source, you have a much wider palette of phosphor colors available to work with.
 
It's all about the phosphors and their excitation wavelength. I suspect that as the wavenelgth of the underlying LED gets shorter, it will open the door to new phosphor combinations. Fluorescents and CFLs use shortwave UV for their source, and UV LEDs are still pretty far away from that wavelength so they can't use the phosphor blends currently in use by fluorescents. While there are shortwave UV LEDs, their power output is incredibly small, their cost is incredibly high, and they're really still in the prototype stage. The thing is when you have a shortwaver excitation source, you have a much wider palette of phosphor colors available to work with.

Could there be brand new technologies (other than phosphors) that open the door to a broader spectrum range?

It seems to me that the problem with phosphors is that when they begin to break down, the led shifts color.
 
Like any other technology, it's simply a matter of time until it's created, then more time until it's affordable. Wait around long enough and some genius will come up with a concoction of chemicals from under his kitchen sink and create a light source and power pack combo the size of an aspirin tablet that costs 25 cents to make and lasts longer than you do. Come to think of it, maybe I should get to snooping around under my sink.... :whistle: :poof:
 
Good point, Marmaduke. Some of the best inventions happened almost by accident (Post-It notes, for example). Even the fluorescent minerals from underground mines were discovered to be fluorescent by accident, opening the door for a whole range of applications from CRTs to fluorescent lamps and white LEDs.
 
IMHO LEDs do have a better color rendition than incan. We're just more used to incan and it gives a "warm" feeling :D

Now that LED has the power to compete ... gone is the ghostly glow and now we see brilliant white cut through the night whereas incan is a dimly yellow glow.
IMHO this problem was a lot about the lack of luminous flux with LED and not a problem per se.

When looking at the spectra of LED and incan ... we see that both aren't perfect at all. They are different. The huge red power in incan is more unnatural than the blue spike in LED.

bernie
 
For applications where color quality is paramount, the current move is toward Red,Green,Blue LED's. I have my doubts about this as the narrow wavelength of monochromatic LED's can cause problems.

- What if you shine it on something with a 'narrow' color between red and green? It is going to look darker than it should. I think the phosphor LED is better because it puts out a range of colors. You can add a red LED to warm it. I would like to see them come out with reddish phosphors, but I guess those must be fairly dim.
 
IMHO LEDs do have a better color rendition than incan. We're just more used to incan and it gives a "warm" feeling :D

Now that LED has the power to compete ... gone is the ghostly glow and now we see brilliant white cut through the night whereas incan is a dimly yellow glow.
IMHO this problem was a lot about the lack of luminous flux with LED and not a problem per se.

When looking at the spectra of LED and incan ... we see that both aren't perfect at all. They are different. The huge red power in incan is more unnatural than the blue spike in LED.

bernie



My overall preference is LEDs by far, but my opinion is different here.

I think that incandescents do a better job of cutting through fog, bringing out outside colors, and reaching out than LEDs do.

When I use even my most powerful LEDs outside, they have an almost 2D feel--the color of the beam makes seeing texture and 3D'ness nearly impossible beyond short range. They also don't really help much with ambient lighting when walking outdoors. Outdoor plants seem faded in color.

Incandescents, when at full power (e.g. before they start shifting color to amber/brown), for me anyway, really work excellently outdoors. The colors come to life, the texture/ 3D'ness peaks, and they can cut through ambient light.

Indoors is another matter. For me, LEDs seem MORE white when on a white wall, while the incandescents seem yellow -- at full power -- to brown at below full power. Even when moving room to room and not just looking at white walls, LEDs seem brighter/whiter indoors.

This is generally why I prefer LEDs indoors, and incandescents outdoors.

An easy way to make incandescents more useful for a longer period of time is to regulate them -- so they don't immediately drop in output after 2 minutes of use. I find that after just 5-10 minutes of use, nearly all incandescents are too amber-brown for my liking--even popular Surefire models. Unfortunately, only the A2 seems to have regulation.
 
For applications where color quality is paramount, the current move is toward Red,Green,Blue LED's. I have my doubts about this as the narrow wavelength of monochromatic LED's can cause problems.

- What if you shine it on something with a 'narrow' color between red and green? It is going to look darker than it should. I think the phosphor LED is better because it puts out a range of colors. You can add a red LED to warm it. I would like to see them come out with reddish phosphors, but I guess those must be fairly dim.

Also, if you need 3 different emitters (one red, one green, one blue), wouldn't they quickly get out of timing (e.g. they each drop in lumen maintenance at different rates), thereby shifting the color output over time?
 
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