Discussion in 'LED and other Lighting' started by GrowLightResearch, Jan 30, 2018.
OSRAM does not have a Duris 660nm deep red. They have a red/orange 623nm.
Calculated from the SPD chart and data from the datasheet.
I do not want to open that can of worms. For me personally, I will only deal with PPFD and do not care about PPF at all. That spec is useless to me.
The osram chip is truly a red only phosphor chip with a wide peak around 650 nm.
I fixed the link in my post. take a look. Its $0.73 on digikey.
I corrected I meant 625nm not 523nm. OSRAM does not have anything over 625nm in the Duris line. They do in the Olson SSL line and a 645nm in the Golden Dragon line.
Your link did not work.
True. Those are the highest efficiency deep reds. I prefer the Olson SSL 150 of the Cree. In deep blue Cree is the best.
I do not think there is such a thing as a PC red. But liar, wow, a little harsh even if they did have one. Show me the Digikey link.
You linked to an orange 620nm. It does not appear to be a PC LED. The Vf is about 6v likely three dice. It could be four 2v dice except the temperature curve drops 20% at 80° C indicative of a native red phosphide and not a deep blue nitride. A deep blue nitride would lose about only about 5% at 80° C.
The 73¢ Duris on Digikey is also a 620 nm, not 650nm.
Read the datasheet.
Does the color of this LED look orange or red?
Is the wavelength say 620nm?
What is the dominant wavelength? (second image)
If you map the crominicity coordinates it's much closer to 620nm than 650nm.
650nm is on the very tip of the red area.
The human eye will perceive the LED as 620 nm because of its spectral sensitivity. Put the SPD and the spectral sensitivity curve of the human eye in one coordinate system and you'll probably see that both curves meet at 620 nm. https://en.wikipedia.org/wiki/Spectral_sensitivity
EDIT: Ah well, Osram did this already in the datasheet. And it doesn't fit perfectly... intersection is at around 612 nm... don't know, maybe they were just rounding?
the spd in the datasheet shows a 650 nm peak. regardless of the exact chromacity its a very nice fat band in red and with lots of overlap into 660nm and into far red 700nm+ which a red mono does not have.
From a photosynthetic point of view, everything past 670nm is quickly becoming useless (https://en.wikipedia.org/wiki/Photosynthetically_active_radiation), therefore I would not recommend this LED for our purpose.
very true regards raw photosynthesis, but its also known that wavelengths in the 700 nm range have significant photomorphogenic effects. Phytochrome responses, shade avoidance, seed germination etc.
That's why I ask the question should I supplement with 660 deep red monos, or with a wider band of red light ?
Well, then you already know what you need to know. Do you want more photons (grams!) or do you want to experiment with photomorphogenic effects?
If grams then 660 nm, if photomorphogenic effects then far red LEDs.
The DURIS S5 are not good in either one of this.
I wish it was 650nm. I don't think the perception thing will fool the plants tough. Until then the solution to a flower LED maybe the Luxeon HE 90 CRI. It is 154 lm/W whereas the Samsung LM561 3000K 90 CRI is 130lm/W. 154lm/W is very good for a very red spectrum.
Obviously this Duris LED is targeted at general lighting. SPDs are not usually luminous, they are usually radiometric. In @alesh "math behind" spreadsheet it converts the SPD's radiometric watts to lumens.
This whole Duris datasheet is a bit weird. The "SPD" is luminous. Plants do not care about human perception. I think the graph in the datasheet is about the eyes red and green cones and showing where 620 falls. Who knows. I'm not going to use it.
The OSRAM hyper red peaks at 660nm and Cree's photo red peaks at 650nm.
Both are narrow band and drop to zero before 700nm.
Hyper red is a little more efficient than photo red. For deep red I use OSRAM hyper red.
In this graph from a graduate level textbook that is considered the plant physiology bible.
This is from the 5th Edition. It clearly shows 660 is better than 650nm. I drew a line at 650nm.
Far red does nothing for photosynthesis. Photomorphogenics will affect the cannabinoid levels and that has nothing to do with photosynthesis. Unfortunately there is very little research published in this area regarding cannabis.
I wasn't even talking about cannabinoid levels ... look up phytochrome, far red shade response and seed germination for just a few effects. Also check out Emerson....
Yes I am very familiar with those aspects of Fr. Old news. Very old news. The terpenoids, flavonoids, phenylpropanoids, and the other secondary metabolites are much more interesting aspects of phytochromes and .photomorphogenics.
I was 2 years old when Emmerson wrote the Dependence of yield of photosynthesis in long wave red on wavelength and intensity of supplementary lightt paper in 1957.
This image may help explain the difference between a blue-red spectrum vs. white. And make a statement regarding far red. I'm an electrical engineer and do not know much about plant physiology. I believe cannabinoids fall in to the bottom half of this table. I see cannabinoids phenylpropanoids, flavonoids and terpenoids in medical cannabis articles. For example these are the key words in this paper.
Cannabis constituents; phytocannabinoids; secondary metabolites of cannabis; terpenoids; flavonoids; phenylpropanoids;
If you look at the BRY and the BRFr vs. just BR, there is a significant difference.
The point being it's not just about photosynthesis. The yellow supports using white LEDs and the Fr as well. Although the effects of Fr work well for some species and not well at all for others. It's a crap shoot.
I'm going to use the BX Gen2 in my next grow to checkout the yellow photomorphogenics. I will start the seedling under just blue and yellow in an attempt to minimize elongation. And I'm going to use side lighting from two sides.
Bridgelux Gen2 3000K 80 CRI
Separate names with a comma.