I am lookin for a LED device which I plan to use for light saturation experiments on small plants. It should provide about 1800 umol photons/m2 in the PAR range. Most researchers use high power (500 to 1000W) halogen lamps but these lamps also need a water filter to block the heat.
Since I wish to avoid the water filter I am looking for a ready made LED light source.
I would appreciate any suggestion
Stefano
I agree with you Dibakar Pal.
Very interesting link.
Regards!
Yes, you can achieve high irradiances with LEDs (I've measured up to 10 000 umol m-2 s-1 with an off-the-shelf 39W LED array (https://www.lumitronix.com/en_gb/smartarray-q36-led-module-39w-neutralwhite-53681.html). To have a spectrum that is not lacking green light, and has a good balance of blue to red you could use daylight/cool-white LEDs (5000 to 6000 Kelvin equivalent which will contain more blue than incandescent lamps) with CRI > 80. Almost all commercial LED lamps will have a very high R:FR ratio, while all incandescent lamps will have a low one.
You do not say how large an area you need to illuminate, and this makes a huge difference in what can be recommended. Please, let us know this. If you are willing to do some simple wiring or not, and whether you want to illuminate a small area like a single Arabidopsis rosette or a gas-exchange chamber or something larger. A supplier of various custom light sources for plant research is PSI in the Czech republic (http://www.psi.cz/), but maybe all you need is a LED light source as available for studio photography from a company like Aputure or Godox (check eBay or your local photography shop). For a small area if the LEDs are packed on a small physical area you will need at most 50 W as LEDs are at least 10 times more efficient than incandescent lamps in the conversion of electric energy into light. Many of the light sources sold for use in photography have a built-in dimmer to adjust the light output between 10% and 100% full output. If you are planning to use one of these sources in the lab make sure to buy one with a socket to connect an external power supply so that you do not need to even buy or worry about batteries. Of course for field use those accepting batteries are preferable. (Tomorrow I will measure the output of one 9W LED light source for photography that I have and post again here).
Thank you Pedro for suggesting the photographic LED panels: I will investigate that and I believe that both price and light spectrum should be OK, although I have not found yet any led combination which produces a continuous spectrum similar to that of incandescent lamps.
In any case I will need to cover a small area, about 20 x 20 cm and I could do some wiring/assembling of spare components, so I if you have any suggestion for DIY solutions I would be very glad to know.
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