LED as True White Light Source

I think these will help....

http://www.ledgrowlightsdepot.com/pages/what-are-the-best-led-grow-lights

"A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p-n junction diode, which emits light when activated.^[4] When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor."

https://en.wikipedia.org/wiki/Light-emitting_diode

ps://www.earthled.com/collections/earthled-growled-series-led-grow-lights

Thanks, SolarEagle! I know it's possible to make LED lamps out of many LED's that together, represent a full spectrum of light. And understand that individual photons of specific wavelengths are based on the specific band gap of the semi-conductor. But if Phosphor can bend some of the light into the yellow spectrum, could it also be used to bend some of the light into other parts of the spectrum?

" ... LEDs have about a 20nm 'bleed-over' on each side of the wavelength (varies with color.) For example, a 380nm diode will fall in the ranges of 360nm-400nm, with 380nm as the peak. "

I guess if you're set up for it, you can experiment with different materials, as to what effect will be obtained, I cannot say with any certainty....

....."the development of the first white LED. In this device a Y3Al5O12:Ce (known as "YAG") phosphor coating on the emitter absorbs some of the blue emission and produces yellow light through fluorescence. The combination of that yellow with remaining blue light appears white to the eye. However using different phosphors (fluorescent materials) it also became possible to instead produce green and red light through fluorescence. The resulting mixture of red, green and blue is not only perceived by humans as white light but is superior for illumination in terms of color rendering, "

http://www.sciencedirect.com/science/article/pii/S0030402611002713

http://www.mt-berlin.com/frames_cryst/descriptions/led_phosphors.htm

http://onlinelibrary.wiley.com/doi/10.1002/lpor.201300140/abstract

https://www.pvlighthouse.com.au/resources/courses/altermatt/The%20Solar%20Spectrum/The%20extraterrestrial%20(AM0)%20solar%20spectrum.aspx

happy smoking

Is this for medicinal purposes, or recreational?

If you have an iphone, you can download this app to turn your phone into a spectrometer:

http://physicsbuzz.physicscentral.com/2013/02/turn-your-phone-into-spectrometer-for.html

Here's instructions to turn any phone camera into a spectrometer:

http://www.wired.co.uk/news/archive/2010-10/11/camera-phone-spectrometer

Finally, here's a gadget that's just being developed. I don't know when it will be available:

http://www.laserfocusworld.com/articles/print/volume-51/issue-06/world-news/spectroscopy-miniature-all-passive-ftir-spectrometer-fits-on-mobile-phones.html

Thanks that app looks awesome! Also, since people seem curious, this is NOT for growing weed. It is for other plants though :)

Here's a comparison of the typical spectrum of a White LED and ordinary Sunlight.

White LEDs emit a significant amount of blue light, which is what plants need for photosynthesis.

Large numbers of greenhouses in The Netherlands, among other places, already use LED lighting to promote growth out of season for plants such as tomatoes, etc.

It isn't necessary to use all of the spectrum, as plants don't need it. Green, in particular, is largely rejected, which is why leaves appear green. So there are economies to be made by not using the full spectrum.

Maybe it's time to Google on the topic and find out what LED-based legitimate plant growers are doing, and why (rhetorical question - NNTR)?

LEDs by their nature emit in narrow bands that correspond to an emission line from a phosphor, or electron orbit transition(This is usually stimulated by an ultraviolet LED). Some are emitted in a solid state laser, which also are narrow bands.

The phosphor can consist of a number of components that emit at different frequencies and are chosen to try to match a particular emission curve, usually black body.

Our eyes may see it as a broad continuous spectrum, but a grating or prism will soon

show the emission line nature of the light.

As for LED grow lights. Refer to the search here. Many articles on it, and sales pitches.

Optimal light varies a little by the plant variety grown.

Well, here's indirect proof of the idea that the "drug wars" we're never working. Pot is now legal in so many places that the premium that buyers were once willing to pay for the risk is now gone, so growers are being forced to economize by looking to energy efficiency. Bravo!

There is a lot of downwards potential. Female flowers create hundreds of seeds per floret, thousands per plant.Once a mailout of good seeds comes along, most people can get by on a single plant per year for themselves, which can be grown with 200 watts of LED light in a plastic covered shower space.All those greedy new entrants will starve. Risk is low if you sell/give nothing away, since those are the leak points for micro-growers

Several years ago I became interested in "light therapy" to overcome SAD (seasonal affected disorder). I went and looked at a "therapy" lamp and was highly disappointed. So I did a little of my own research and bought a four foot four tube fluorescent fixture and hung it above my bathroom mirror. I get my light therapy while brushing my teeth and whatever else I might happen to be doing. It does seem to help. When I come staggering into the bathroom early on dark Winter mornings and kick on the "Kleig" lights, I. WAKE. UP.

Another thing I found out was that color corrected halogen lamps produced the most natural light spectrum. But they are energy hogs. I would still like to experiment with them by placing a couple of light bars on either side of my bathroom mirror. But who knows. The way LED technology is advancing it might not be necessary.

When I was taking a drawing class I was having difficulty seeing fine detail so I went to a lighting store and purchased a full spectrum bulb. Having the higher frequency output helped with the finer details. Then I discovered one of my friends paid a lot of money for an Ott-Light so she could see to do sewing. My bulb cost only five dollars. Now I see where Ott-Light is LED powered and you can vary the brightness and color.

You need to determine which "white light" you wish to emulate.

In colour matching and verification, there are multiple variations of "daylight". Typically you will see fluorescent lamps nominated as D65 or D85 where the number represents the angle of the sun above the horizon.

If you're talking about white light as prescribed for automotive headlamps, then there is a very limited range in the colourtemperature spectrum that would qualify as "white".

As previously indicated, the available wavelenghts from LEDs are limited by the physics of the energy changes of electrons.

Thus it is not possible to have (as you requested) an individual LED to give a larger portion of the spectrum.

I worked for a company where LEDs were supplied in "BIN lots" sorted by dominant wavelength into 2nm groupings from a single parent wafer, but even then there were only certain colours available across typically 40nm spread.

We were investigating manufacture of LED headlamps for cars. White was a visual perception, but never a complete spectral distribution. This was achieved by combination of multiple chips into a single LED package, but he spectral distribution was peaky in the dominant wavelenghts and absent elsewhere.

I noticed in the spectral curve of sodium vapor lamps there was huge peak right at the orange part of the spectrum and not much anywhere else.They worked good for night lighting because the human eye is more sensitive to longer wavelengths. Recently the local power company has been replacing the sodium vapor streetlamps with white LEDs and everybody hates them. We liked the warm glow of the orange lamps. We loved it when they replaced the ice cold blue mercury vapor lamps with sodium. The mercury vapor would give me goosebumps even in the Summertime.

https://microsunlamps.com/blog/

https://microsunlamps.com/about-microsun/

Hey, has anybody mentioned MicroSun yet?

Go with your RGB variable LED's. Different plants require different spectrums. Some like the bluer end of the light while most prefer the red. This way you can adjust what makes them grow better. Some good grow systems don't even use white light.