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Conundrum

Mon Dec 24 2012, 06:52PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Hi all.
Has anyone managed to find out how thin EL sheet can be made, say 50um?
Thanks!

-A

Proud Mary

Mon Dec 24 2012, 08:26PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

You need

High Luminance from Thin Film Electroluminescence Devices

which is here:

The authors discuss luminance and radiance in a one micron ZnS:Mn film on ITO excited at up to 150 kHz.

Good old zinc sulphide seasoned with a jigger of manganese -- none of your fancy rare earths imported from China, or organic scintillators that started life in an oil refinery.

Just your cup of tea, I'd say.

Conundrum

Tue Dec 25 2012, 02:49PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Interesting, thanks!
Trying to figure out how to salvage manganese from a broken road lamp battery, MnO2 isnt any good and yields no EL activity though it does glow under UV.
Would heating it in the presence of carbon using an induction heater or electric element work?
MnO2 + C + heat = Mn (m) + CO2
As it is pretty reactive, treating MnO2 with hydrogen would also work.

Proud Mary

Tue Dec 25 2012, 03:31PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Conundrum wrote ...

Interesting, thanks!
Trying to figure out how to salvage manganese from a broken road lamp battery, MnO2 isnt any good and yields no EL activity though it does glow under UV.
Would heating it in the presence of carbon using an induction heater or electric element work?
MnO2 + C + heat = Mn (m) + CO2

Method of making zinc sulfide electroluminescent phosphor particles. US Patent 5273774

ZnS:Mn electroluminscent powder can also be made by heating together ZnS powder with a manganese compound for 1 - 2 hours at 850 - 1050Â°C in a nitrogen atmosphere, see:

Method of making a manganese-activated zinc sulphide electroluminescent powder. US Patent 3984586

Pinky's Brain

Tue Dec 25 2012, 05:55PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
Location:
Posts: 837

So, "all" you need is a ball mill, a bottle of N2 with a regulator and a small electric kiln airtight enough you can keep it flooded with N2 with a low gas flow? :)

Proud Mary

Thu Dec 27 2012, 08:17PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Pinky's Brain wrote ...

So, "all" you need is a ball mill, a bottle of N2 with a regulator and a small electric kiln airtight enough you can keep it flooded with N2 with a low gas flow? :)

We-ell, the 'all' might be quite a lot of work, but none of it is too difficult, costly, hazardous, that you couldn't succeed at it in the home workshop.

Conundrum

Thu Dec 27 2012, 11:41PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Wonder if Jeri's method of heating it under glass beads (I have some of those) in a fragrance sampler would work here? Maybe use that induction cooker I have and rewind the spare coil into a toroid..

Pinky's Brain

Fri Dec 28 2012, 06:59PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
Location:
Posts: 837

The glass frit Jeri used can serve as an atmospheric barrier, but it can't reduce the MnO2.

AFAICS your fragrance sampler would either shatter or melt.

Conundrum

Sun Dec 30 2012, 01:16PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

It worked, once.
I did get a bright glow under UV, the tricky part is then grinding the phosphor without a) getting water in it, or b) making the resulting particles too small to work.

See

recently on H-a-D, seems he is using a different technique for making the top coating.

Actually there is a way to make it brushable. Supertex now sell a single chip EL driver which is 0.1*0.1mm in chip scale so in theory an induction based system I came up with would be able to receive 13.56 MHz ISM band on its IC scale coil and flash the EL directly above the chip if the 16 bit address matches.
This would allow for video speed updates and thanks to Moore's Law thousands of these could be made in little glass or UV set polymer for $10/1000.

Comments?

Conundrum

Sun Sept 25 2016, 07:40AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Relevant patent, please add to archives.

Also interesting, someone is claiming a full spectrum EL can be made which starts red at 90Hz and shifts to near UV at 2000Hz.
I think its a variant of SrS but using two dopants possibly Au and Bi.

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