LUXEON Rebel Phosphor Converted Amber

Sorry if this was posted elsewhere, but I found this to be an interesting breakthrough:
LUXEON Rebel Phosphor Converted Amber

Imagine if they use similar technologies to make Red or Red/Orange more efficient, too! Green is already more efficient in parallel to the advancement of the Royal Blue and Blue dies. Now for an efficient RBG or RBGA fixture, the reds are the only thing holding us back.

For the heck of it, I may get a few and replace my lousy amber turn signal lamps with these. The old amber emitters were plain disappointing. The spectrum is a bit more wider than the old Amber, so I wonder if these will be more pleasing to the eyes.

-Tony

Thanks for the info. I have been looking for high output Amber LEDs for the Firefighters line of flashlights that we are developing. Amber is the best color with far less reflection from smoke than white light.

Curt

Amber is the best color with far less reflection from smoke than white light.

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?

Explain please.

Please tell me this isn't an extenstion of the urban myth that yellow/orange fog lights have less scatter than white/blue.

Why do you think it is an urban myth?

blasterman said:

Please tell me this isn't an extenstion of the urban myth that yellow/orange fog lights have less scatter than white/blue.

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Try this one on for size: Why is the sky bue?

Try this one on for size: Why is the sky bue?

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Rayleigh scattering (and I refuse to wear you clothes)

To be more exact, the Raleigh Effect of photons bouncing off of Oxygen and Nitrogen in the upper atmosphere causing the dominant blue color of the sky, has little relation to fog lights and smoke.

The bunk on this starts from the urban myth that longer wavelengths of light are more likely to be reflected than shorter wavelengths. The fact is that particle scattering occurs when the wavelength of light is in a specific relation to the size of the particle; molecule/dust/fog or other. Atmospheric Fog, the last time I checked was composed of water droplets and not dense areas of Oxygen and Nitrogen clouds at sea level. Maybe if you lived on Venus.....

Also, last time I looked at the clouds in the sky (also composed of fine water droplets like fog) they were white. If the fog light bunk were true, then a white light shining in fog, or sunlight off a cloud would appear color tinted off axis because a specific wavelength were being favored via either refractive or transmissive scattering. Do the Halogen headlights of an oncoming car look bluer in fog? No. According to the yellow fog light myth, they should.

I set up fog/smoke machines for light shows, and amber/red/yellow are actually the easiest to see off axis compared to blue.

The Firefighter thing has more to do with contrast sensitivity of the human eye in poor visibility, and in this respect longer wavelengths and shorter wavelengths aren't all created equal.

OK, I hear ya. ...doing some homework.

2xTrinity said:

...our eyes shift toward being more sensitive to blue light at night, and that most objects outdoors preferentially reflect red and green, few things in nature reflect blue. However, fog reflects everything indiscriminantly, so contrast ratio between the illuminated fog and your illuminated object will be much worse.

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blasterman said:

Rayleigh scattering ...

Also, last time I looked at the clouds in the sky (also composed of fine water droplets like fog) they were white. If the fog light bunk were true, then a white light shining in fog, or sunlight off a cloud would appear color tinted off axis because a specific wavelength were being favored via either refractive or transmissive scattering. Do the Halogen headlights of an oncoming car look bluer in fog? No. According to the yellow fog light myth, they should.
...
The Firefighter thing has more to do with contrast sensitivity of the human eye in poor visibility, and in this respect longer wavelengths and shorter wavelengths aren't all created equal.

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Maybe also blue sensitivity at lower light levels? The human eye is most sensitive to yellow and green ...in general, so that may have something to so with fog lights being yellow in addition to the higher ratio of target reflection to illuminated fog.
2xTrinity has a lot more to say about the foggyness here:
https://www.candlepowerforums.com/posts/2842629&postcount=8

Interesting stuff.

It isnt just Rayleigh scattering, but also Mie Scattering. A comparison to clouds/fog to soot is only valid if

1) the index of refraction is similar
2) the diameters are similar.

Neither is the case.

I don't care about the science, if it tricks my eyes into seeing more details, what does it matter that my eyes are being tricked if I'm seeing more details?

Everyone shouldn't decide what they believe based on words when they are trying to decide on something visual.

Caution: Placebo effect.

Sometimes you need to be sure you are actually seeing a difference and not just thinking you are seeing a difference.

I say, if an amber light helps you see stuff that you couldn't see before, use the amber. but also be wary of Gomer's point. Make sure you actually are seeing more.

Water droplets are nice little spherical drops of water which makes them wonderful retroreflectors..... just like the glass beads in pavement stripes and some other retroreflective materials. Over the visible band, water droplets should reflect back pretty equally.

The issue is more one of eye sensitivity and eye response. White light reflected back will be perceived as brighter and given the short wavelengths will cause your iris to close up and hence kill your night vision.

Semiman

With current LED technology, it is difficult to produce yellow to yellowish-green wavelengths efficiently. For this reason, a number of companies are manufacturing phosphor-converted color LEDs, which range from yellow-green (lime) to orangish-yellow (amber).

Philips manufactures the Luxeon Z Lime and PC Amber. The Lime is more of a greenish-yellow color, with a very high 190 l/w efficiency.
The PC Amber is useful for customizable-color changing LED fixtures, where better color rendering ability is desired, since phosphor-converted LEDs have broader spectral bandwidth coverage than bare LED emitters that emit a single discrete wavelength.

Cree manufacturers a PC Amber in its XP-E2 line.

Then there is the QT Brightek PC-amber