Help with EL Sheet products

kbonk · Sep 1, 2003

Hi All,
I am looking for any info on EL sheet, I have a project and am looking for suppliers, info on what people have used and general experiences.
I need to develop a 30" square with 20" cut out of the center. Can I remove the "backer" "black out" side of the EL sheet and have some light excape out the back?
any info would be great
K /ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/help.gif

James S · Sep 1, 2003

There are lots of different kinds of the stuff with different colors and different requirements in supply voltage. I have some larger pieces that can be connected directly to line voltage and light up just fine. Though a higher freequency supply at that voltage or higher may be necessary for some.

You can get some that can be cut the way you want. But I think you may be better off getting wide strips to make the square rather than getting a huge piece and cutting out the middle.

The pieces I have I've always gotten surplus, allelectronics.com and other such places always have some pieces for sale of various sizes and colors. If you want production quantities or larger sizes you're going to have to find the manufacturers. I've never worked with them at that level, so I can't point you to any more info on that side. allelectronics.com also sells inverters that can run them from regular battery voltage.

kbonk · Sep 1, 2003

I need to do this for a commercial project, if I do use (4) 5" strips will I need to jump from one to the other? If I use a single square can I have only one connection to the sheet? ho far away can the inverter be?are there any good sources of info which I can read about the do'is do and do'is donts. I am in research mode now
thanks

JSWrightOC · Sep 1, 2003

EL works by sandwiching a nonconductive phosphor between two electrodes, one (or possibly both) of them transparent. An AC voltage is applied between the electrodes, and the entire unit acts as a capacitor. The higher the frequency, the higher the current flow because of capacitive reactance. Contiguous sheets of EL material can be powered from one location (there are usually tabs protruding from one or more locations for providing power) though larger sheets may require multiple connection points for even lightning. A 5" square piece should work fine with one connection point, but again this depends on the manufacturer's specifications.

If you simply use 4 5" strips, you will have to make connections to each one. You can power them all from the same inverter, as long as it is capable of the power output. Again, check the specs of the EL and the inverter if you can.

As for lenghts of cable runs between the EL and the inverter, the shorter the better--you are dealing with a high frequency signal. The wiring can act as an antenna, radiating this signal resulting in lots of EMI. If you need to make long runs, I suggest some kind of coaxial cable that can handle the voltages involved (most types will). Considering the size of today's inverters, this may be inappropriate.

One last note--connecting the EL directly to the mains supply can be done, though it is certainly a lot safer to use an isolated supply, and one of lower voltage. This mandates a higher frequency, but that in turn means smaller reactive components and makes portable applications feasible.

Enjoy! /ubbthreads/images/graemlins/smile.gif

Doug Owen · Sep 1, 2003

20 or so years ago I was involved in just such an exercise. A custom made odd shape EL panel was used as a backlight on a flex membrane switch assembly and they were 'turning dark in the oven'. Coast Guard requirements (it was for marine use) required 100% testing 12 hours at zero C, 100 hours at 50 C. We had problems. The design was done by long gone consultants, I was responsible for Production, and the Old Man was on my case big time.

Most of what's been said fits with my experience, with a few exceptions. Within reason, the high voltage converter can be a fair ways away. We fed it up a two conductor lead (not even twisted) 8 inches or so long running across the 'front end' of a very high gain (145 dB) radio 'front end' without problems. The frequency we used (high audio) and 'rounded wave shape' simply didn't have significant energy ar RF. Drive it with anything close to a sine wave and you're probably not going to have problems, either. Driving more than one panel from the same source lead to differences in lighting level. Tooling costs for the custom panel were reasonable, in the hundreds of dollars as I recall. It was a set of 'die rule' punches for the various sheets involved in the sandwich.

IMO the call for you is to identify your vendor and *work with him*, he knows what's best. If you choose the right one, he's 'been there, done that'.

Doug Owen

LED-FX · Sep 1, 2003

For strip try:

http://www.e-lite.com/

You can also get EL `printed` to spec by some manufacturers.

As far as I remember Seiko are one of the big names in EL.

Also EL has limited life span , higher frequency=higher brightness, think of sheet as capacitor, and shorter life.

Adam