Physics Talk

dlruckus · Guest

Hi. I have a question as to what sort of changes in peak wavelengths
might be expected in LEDs when the current is varied across them. Can
there be significant shifts? I am thinking of normal useage ranges not
catastrophic currents.
I'd be appreciative of input from those who might know something of
this.
Thanks
Duane

Markus418 · Guest

I can suggest you this book:

Light-Emitting Diodes, by E. Fred Schubert
see homepage:
http://www.rpi.edu/~schubert/

Markus

Guest · Posted: Tue Jun 05, 2007 6:20 am Post subject: Re: LED spectral stability

The Schubert book in the other reply is a very good reference.

The short answer to your question is yes, LEDs can shift significantly
in wavelength, especially if you overdrive them. I've seen them change
dramatically right before they fry. Even before that, you could see a
3 to 5 nanometers shift, which may or may not be significant depending
on your application.

- Dave

On Jun 3, 10:09 pm, dlruckus <d...@earthlink.net> wrote:

dlruckus · Guest

Dave thanks, both to you and to Markus.
I will do some time,temperature and current vs wavelength studies
with the specific components to see what can be done.
I don't expect to stress the LEDs so I suspect, with controlled
currents, temperature changes will be the dominant error vector.
Stability is of more importance to me than exact wavelengths.

Regards
Duane

On Jun 4, 9:20 pm, d...@wyble.org wrote:

art.springsteen@gmail.com · Guest

Duane,

For reference LED's, such as those distributed by INPHORA, not only do
the LED's have heat sinks attached but also have Peletier(sp?)
coolers attached. That is really the only way to keep the colors from
shifting significantly- as Dave posted, up to 3-5 nm. Cool and current
controlled is good, heat is bad...

Art Springsteen

On Jun 5, 3:08 pm, dlruckus <d...@earthlink.net> wrote:

dlruckus · Guest

Thanks Art.

Regards
Duane

On Jun 5, 10:14 pm, "art.springst...@gmail.com"
<art.springst...@gmail.com> wrote: