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Invention? Electrolumincense foil as microscope backlight!

These EL (Electro Luminicense) foils are for LCD backlight. They make nice even light, you can cut them in shape too. Run on about 80V AC, little converter makes it run on battery from .7 to 5 V.

My first idea was to use it as message board...

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put it in front of window, text can be written with a marker, and wiped off the plastic. Then I realized it could work as microscope backlight, always there is this problem when looking for alien life forms etc, to get even light, either with a mirror or some sort of bulb. I tried it at 5V, and it works ! This is how much light (with bright surrounding fluorescent light) it gives at

5V!
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If I can find the adaptor I will later perhaps post a picture of a sample under the microscope with this as backlight. Color could be better perhaps...

Has been done before? If not hereby donated into the public domain. Mention Jan Panteltje on your product :-) :-)

Reply to
Jan Panteltje
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How do you keep 'em dry when cut? I used to work for an EL panel company. Keeping moisture out was a MAJOR issue.

Reply to
mike

On a sunny day (Sat, 29 Dec 2012 10:09:09 -0800) it happened mike wrote in :

Well, I guess you should not cut them when you are going to expose it to moisture, or embed them in some extra plastic (foil). That should not be difficult, perhaps some plastic spray would already do. The shop who sold me these stated they can be cut. You do not have to cut these to use as microscope backlight, just put under the glass.

Reply to
Jan Panteltje

moisture,

I've been out of the biz for almost two decades. Maybe they're better now. At the time, moisture was a BIG deal. There was more than enough humidity in a dry climate to seriously shorten the life of EL. Plastic wasn't nearly dense enough. You can see it in the EL night lights. They rarely last a year.

The place I worked fused another glass pane on the back and filled the gap with oil.

Reply to
mike

On a sunny day (Sat, 29 Dec 2012 16:23:03 -0800) it happened mike wrote in :

moisture,

Interesting, seems today same problem with OLEDs (organic LEDs). I did read some datasheet of an OLED module, and they were paranoia about moisture too. Don't know how long these strips I have will last, but for microscope work they would not be on 100% of the time. I will run one continuously for a while, but humidity is pretty low here, 60 to

70 percent. The generated heat should evaporate moisture too?

The other idea I had was make a big 7 segment lighting clock with these strips, I can get them cheap.. To switch the AC put each of them in a bridge,

29 strips (1 for the double dot between hours and minutes), 28 transistors (no multiplex) and 2 20 pin PICs [because I have many of those] (one forwarding time via logic level RS232 to the next one, and one power sine wave generator with output AC stabilization (driven from 1 PIC PWM out, as switching in more or less segments changes load... Just enough pins! I am just put of a bit by the color of these things, brightness is really good.
Reply to
Jan Panteltje

Did not find the adaptor, at least not all parts of it... made some shots with tripod and camera above microscope:

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Sorry if focus is not 100%, very difficult to do it that way (super macro manual). Anyway, although the EL foil is slightly speckled, this does not show, as the speckles are out of focus when focusing on what you want to see.

Reply to
Jan Panteltje 

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You can get EL in different colors, and you can also shift the color 
towards blue by increasing the frequency of the driving voltage.
Reply to
John Fields

On a sunny day (Sun, 30 Dec 2012 13:27:04 -0600) it happened John Fields wrote in :

good.

Thanks. Yes I have observed the color change. White would be nice. Having different colored strips would also be nice.

Reply to
Jan Panteltje

good.

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http://www.e-lite.com/catalog/
Reply to
John Fields

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manual).

I would have thought that one of the modern white LED packages with a flat face, and roughly 120 degree radiation pattern would make a good microscope light. At least adjusting the current would change the brightness without much change to the color temperature, unlike what happens with a filament lamp.

You do have to be aware though that any 'white' phosphor source has in fact a lot of spikes and dips in the actual output with frequency. Probably the same applies to EL lights. Sometimes this might make the color rendering misleading.

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Regards, 

Adrian Jansen           adrianjansen at internode dot on dot net 
Note reply address is invalid, convert address above to machine form.
Reply to
Adrian Jansen

5V!

under the microscope with this as backlight.

Like i said before,NOT an invention.

Reply to
Robert Baer

On a sunny day (Sun, 30 Dec 2012 14:19:19 -0600) it happened John Fields wrote in :

good.

Hey, nice stuff. I really did not know they made pure white. It is US based, and no prices, and no rep in Europe it seems. Could become expensive ... Now that I know whioe exists I will google locally a bit to see if anything comes up for small quantities. Thanks!

Reply to
Jan Panteltje

On a sunny day (Sun, 30 Dec 2012 14:19:19 -0600) it happened John Fields wrote in :

PS ebay has it all,

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Look at the pictures of these guys! :-)

Reply to
Jan Panteltje

5V!

the microscope with this as backlight.

That's pretty cool. I can see a Raspberry Pi project coming up using those things. Where did you get them?

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has them, but they seem a little pricey - or is that normal cost?

Reply to
G. Morgan

comes up for

Here are some prices:

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Reply to
G. Morgan

On a sunny day (Mon, 31 Dec 2012 06:28:22 -0600) it happened G. Morgan wrote in :

comes up for

Thanks. It is expensive, been looking on ebay, China has it all..

Reply to
Jan Panteltje

On a sunny day (Mon, 31 Dec 2012 06:23:03 -0600) it happened G. Morgan wrote in :

5V!

under the microscope with this as backlight.

I will keep my source secret [*] for now, but I pay 1 Euro a strip inclusive converter.

  • Need to get some more, not sure how many they have available.
Reply to
Jan Panteltje

J.F. mentioned the color change for these EL displays with increasing frequency. I decided to test it, and used sgen Linux signal generator, and my audio power amp. Power amp directly does not do much, not much peak to peak output voltage, you can see something, but not bright. So I added a small 1:10 audio step up transformer.

Started at 22kHz, -> blue

10kHz blue 8 kHz green blue-blue and then lower more greenish.

While switching between frequencies (wanted to try a sweep actually), the amplitude got a bit above what the EL strip could handle, and flashover happened. No way to restore, not even after cutting a piece off, flashover at where the connections are.

Next got an other one and measured capacitance:

109.045 nF Now that was a surprise, I expected some pF, maybe a nF, but not a hundred nF. So driving it in resonance seems the way to save energy. The blue color shift seems to come from increased current at higher frequencies?

OK, learned something.

Reply to
Jan Panteltje

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