Alex ,here's a rough idea ,but nevertheless worth of further testing ....
A two (or four ) channel COB ...
The outside LES "ring" is using a
broadband red phosphor ,with a peak of 640 nm .
Why not 660 nm ?
1) 640 peak red phosphor still emits plenty of 660 nm light ,but also " fills " better
the "lower " red region ,thus "taking care " for both the ChA nad ChB absorption peaks and supplying the highest RQE red light ( 600-620 nm ) .
2) Less power is wasted in the NIR region of over 730 nm ,than when utilising 660nm peak broadband red phosphor .
(as the latter is converting too much of excitation energy into unwanted and useless NIR radiation.)
3) Stokes shift losses are less with a broadband 640 nm phosphor ,than with the broadband 660 nm one.Thus a higher radiometric efficiency is achieved ,when utilising the former.
The inside LES circle is a mix of
green and yellow phosphors*
This phosphor mix will emit a cool white light of ~ 5000 °K ,80-Ra .
(* can be GAL (Aluminate ) or NYAG ( Garnet) phosphors ,
but rather not Silicate ones, due to the relatively large particle size - D50(V)- of the latter )
If this COB outputs
totally 1500 umol/sec ,then it could be "broken down " to something like that :
Channel #1 ( 5000° K )
400-499 nm : ~250 umol/sec (peak 450-455 nm )
500-599 nm : ~400 umol/sec
Channel #2 ( broadband 640 nm )
600-730 nm : ~850 umol/sec (peak 640-645 nm )
......
Just a rough idea ,there ...
With the use of dimmable drivers and this COB ,the grower can possibly achieve quite a few things ...
During seedling and early vegetative stages of plant growth ,the grower can set
the Channel #1 at 100% output and channel #2 at 20% output ...
~820 umol/sec totally ,is more than enough radiation for a vigorous vegetative growth ..
Plus the fact ,that the spectrum emulates closely enough ,the sunlight during early spring ,
thus resulting in a greater female:male ratio of plants and a "stocky " stature .
From late vegetative growth to midst of flowering ,the grower can have at 100% ,both channels ...
And then ,during late reproduction stage (towards harvest ) ,the grower can
set the channel #1 at 20% and channel #2 at 100% ( total ~980 umnol/sec ) ,
so to avoid the unwanted foxtailing and the degradation of the cannabinoids
(trichomes turning amber/brown ) ,due to high energy / short wavelength photons.
Throw in a microcontroller ,and then the " spectrum shift " will be handled automatically ,
during the whole growing cycle ..." Spring light =>Summer light => Autumn light " ....
Alex ....
I'm hoping that you and the rest of the FCO team ,will think it over ...
You can always make some "beta" CObs and let us do the actual testing ..
Cheers.
