Question on Wavelength.

The manufacturer datasheet for a luminous brand COB. Has a chart on Wavelength. Percentage verses Wavelength.

The chart shows a single 3000k chip, driven at 100%. Has a wavelength of 450nm. Driven at 70% it's ~575nm.


What am I looking at here? What wavelength should it be?

SouthCross said:

The manufacturer datasheet for a luminous brand COB. Has a chart on Wavelength. Percentage verses Wavelength.

The chart shows a single 3000k chip, driven at 100%. Has a wavelength of 450nm. Driven at 70% it's ~575nm.


What am I looking at here? What wavelength should it be?

Click to expand...

You have to show the pic to have a chance of someone explaining it for you.

This isn't the chart for the chip but shows an example.

http://aemstatic-ww2.azureedge.net/content/dam/leds/PrintArticles/volume-12/issue-10/1510LEDs_F6f1.png

Here is another chart example.

that last chart is a good explanation of spectra as it shows the actual color at each wavelength

in a cob spectrum chart:

sharp blue peak= light from the actual monochromatic blue diodes
broad yellow/green/orange/red peak is created from the yellowish silicone layer on the top of the chip

it is "phosphorescent" and creates green/yellow/red light when the blue light shines thru it

resulting "color temp" of the mixed spectra is controlled by composition and thickness of the phosphor layer and the relative ratio of green/yellow/orange/red to the blue peak

basically mixing multiple primary colors to make "whitish" light

SouthCross said:

The manufacturer datasheet for a luminous brand COB. Has a chart on Wavelength. Percentage verses Wavelength.

The chart shows a single 3000k chip, driven at 100%. Has a wavelength of 450nm. Driven at 70% it's ~575nm.


What am I looking at here? What wavelength should it be?

Click to expand...

In other words... you were misunderstanding the intent of the graph. On the chart you posted, the percentage on the x-axis is not how hard these cobs are being driven, but it is giving the different parts of the color spectrum a percentile mark based upon how much of that color is present. The 5000k has a high peak in blue but a much lower peak in red. Conversely the 2700k has a very small amount of blue compared to the amount of red, and you can see that the red peaks at 650nm. It also looks like the person who made this chart screwed up since no part of the 2700k spectrum is touching 100% (that red peak should be hitting 100%, not 90%)

Now I'm on point.

At 100% the chip runs more towards the blue side. As the driven % drops the chip runs towards red.

So with the 3000k 'cool white' chip. I can run it at 100% in veg for the benefits of the blue. In flower, I can lower the driven % for more red.

I'm I correct?

SouthCross said:

Now I'm on point.

At 100% the chip runs more towards the blue side. As the driven % drops the chip runs towards red.

So with the 3000k 'cool white' chip. I can run it at 100% in veg for the benefits of the blue. In flower, I can lower the driven % for more red.

I'm I correct?

Click to expand...

Not really. Think of those graphs as a way to show ratios. You are getting all of that light and adjusting the current doesn't affect the CCT really that much.

So for the 3000k think of it as for every 1 photon at 650nm you're getting .4 at 450nm. Obviously this is a gross oversimplification but it helped me.

SouthCross said:

At 100% the chip runs more towards the blue side. As the driven % drops the chip runs towards red.

Click to expand...

spectrum is nearly identical at all currents. that graph shows photon output, not power input

SouthCross said:

Now I'm on point.

At 100% the chip runs more towards the blue side. As the driven % drops the chip runs towards red.

So with the 3000k 'cool white' chip. I can run it at 100% in veg for the benefits of the blue. In flower, I can lower the driven % for more red.

I'm I correct?

Click to expand...

Yeah, you're still thinking "if I do this, then this is what happens". Nope. Those charts simply record the different wavelengths that a particular temperature cob produces as soon as you turn it on. Each temperature cob on that chart has a different mix of blue, green, yellow, red light (and everything in between). That chart simply shows you how much of each color there is, right down to the nanometer.