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Unforseen Variability of blue LED Peak!

Unforseen Variability of blue LED Peak!

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I didn't know this. When shooting, I lit a clear MV lamp as a reference and placed it just far enough so that I can just make out the Hg lines. The prominent blue line is the 436nm and the green is the 546nm mercury lines. The double yellow lines are at 577/579nm. Photographed various LED I had from flood to household Edison screw lamps to indicator lamps. I was a bit surprised to see the peak can range from almost 438 to 455 nm.

SpectraCompsosite.jpg Circadian-vs-LED-Scotopic-P.jpg IMG_3970-LED-measured.jpg MeasuringLEDPeakMin.jpg

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Album name:lights*plus / Lamp Spectra
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Date added:Apr 11, 2018
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dor123
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Apr 11, 2018 at 04:36 AM Author: dor123
I know that the peak wavelength of the blue LED, varies between LEDs. This is also true with UVA, near UV, violet and green InGaN LEDs.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

rjluna2
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Apr 11, 2018 at 06:22 AM Author: rjluna2
Oh I see, you were using the clear MV bulb as a reference here

Pretty, please no more Chinese failure.

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Apr 11, 2018 at 06:28 AM Author: F96T12 DD VHO
Why does every LED seem to have that space in between blue and green

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dor123
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Apr 11, 2018 at 06:40 AM Author: dor123
The blue emission and the and rest emission is produced by two different things: The blue emission comes from a blue LED, and the green-yellow comes by a phosphor coating, that why that space exists between the two separate emission.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

F96T12 DD VHO
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Apr 11, 2018 at 06:45 AM Author: F96T12 DD VHO
Ok thanks that always really confused me

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Apr 11, 2018 at 02:15 PM Author: merc

Oh I see, you were using the clear MV bulb as a reference here

Thanks, Robert. Now I know what he is speaking about.
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Apr 11, 2018 at 03:10 PM Author: Medved
Why do you think it is unforeseen? You may easily make this type of LED anywhere between about 500 down to 300-ish nm, it is just a meter of optimization (some applications and/orphosphor composition suit better shorter wavelength, some loger).
But it is quite common for a cheap products to not use any exact specification, but "WhatseverIsJustTheCheapestOnTheMarketToday", so sometimes the cheapest is 438nm, week later 450nm, so obviously the production then varies (and the phosphor is then either designed as some compromise, or sourced the same way as well)...

No more selfballasted c***

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Apr 11, 2018 at 03:21 PM Author: lights*plus
I knew of a small variability from one LED to another, depending on the driving current or other driving parameters. But nearly ~10 nm in the blue InGaN peak?

According to the mercury lines, the phosphor looks much more consistent!
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Apr 11, 2018 at 03:31 PM Author: Medved
The LED wavelength could be varied indefinitely according to the wish, the phosphor radiation is given just by the used doping elements and you can vary just the amount (the typical LED phosphor uses at least two components, so you may vary their ratio and then the total phosphor amount).

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Apr 11, 2018 at 03:55 PM Author: lights*plus
We can see that all or most of the energy is kept in the visible section of the spectrum. Why is the lighting industry using just InGaN for a blue emitting and irradiating source? Could they have used (are there any) violet or green LED emitters that can irradiate a phosphor?

I would imagine if the material for the phosphor is the same, then it would (re)-radiate in the same region of the spectrum from one LED to another. Medved, do yo know the two components for the phosphor?
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Apr 11, 2018 at 05:29 PM Author: rjluna2

I knew of a small variability from one LED to another, depending on the driving current or other driving parameters. But nearly ~10 nm in the blue InGaN peak?

According to the mercury lines, the phosphor looks much more consistent!


Due to the size of the LED die, the variable becomes magnified which I would imaged. Same goes with the hfe (I can't seem to use the subscript code here) variable as common bipolar junction transistor. You try to put two different pairs of transistor as the Darlington transistor and another pair as well, you will get different value at the output.

https://en.wikipedia.org/wiki/Bipolar_junction_transistor#h-parameter_model

Pretty, please no more Chinese failure.

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