Electroluminescent Panel Failures - What's the Cause?

[Mark & Mary Ann Weiss]

A fair amount of electronic equipment utilizes EL panels to backlight the
LCDs.
Some of the EL panels fail rather abruptly after a short time (a year),
growing dim, unevenly lit, etc.
A check on the inverters generally reveals a healthy 200v p-p sine signal
feeding the panel, so the panel must be bad. Some panels seem to recover a
bit and regain some level of illumination, though not as good as new.

So here's the question:
What's going on in the panel that causes it to lose brightness?
I understand that an EL panel is a capacitor, with phosphor-coated
dialectric.
The only thing I can think of is that somehow the layers have been infused
with moisture or oxygen, causing the luminence properties to degrade.

Can a panel be rejuvinated through either heating, cooling or drying out?

Anyone here an expert on EL panels?


--
Take care,

Mark & Mary Ann Weiss

VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
Hear my Kurzweil Creations at: www.dv-clips.com/theater.htm
www.basspig.com The Bass Pig's Lair
Business sites at:
www.dv-clips.com
www.mwcomms.com
www.adventuresinanimemusic.com
-

[TKM]

Post by Mark & Mary Ann Weiss
A fair amount of electronic equipment utilizes EL panels to backlight the
LCDs.
Some of the EL panels fail rather abruptly after a short time (a year),
growing dim, unevenly lit, etc.
A check on the inverters generally reveals a healthy 200v p-p sine signal
feeding the panel, so the panel must be bad. Some panels seem to recover a
bit and regain some level of illumination, though not as good as new.
What's going on in the panel that causes it to lose brightness?
I understand that an EL panel is a capacitor, with phosphor-coated
dialectric.
The only thing I can think of is that somehow the layers have been infused
with moisture or oxygen, causing the luminence properties to degrade.
Can a panel be rejuvinated through either heating, cooling or drying out?
Anyone here an expert on EL panels?
--
Take care,

Electroluminescent panels are historically notorious for being very
sensitive to moisture so anything that damages the panel seals and allows
air or water to leak in will cause problems.

Terry McGowan

Post by Mark & Mary Ann Weiss
Mark & Mary Ann Weiss
VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
Hear my Kurzweil Creations at: www.dv-clips.com/theater.htm
www.basspig.com The Bass Pig's Lair
www.dv-clips.com
www.mwcomms.com
www.adventuresinanimemusic.com
-

[Ian Stirling]

Post by TKM

Post by Mark & Mary Ann Weiss
A fair amount of electronic equipment utilizes EL panels to backlight the
LCDs.

<snip>

Post by TKM
Electroluminescent panels are historically notorious for being very
sensitive to moisture so anything that damages the panel seals and allows
air or water to leak in will cause problems.

Is baking at 110C, for many hours likely to remove the water?
Or will it have chemically bound.
(assuming it's just diffusion, rather than an out-and-out failure, and
assumign that everything doesn't melt)

[SQLit]

Post by Ian Stirling

Post by TKM

Post by Mark & Mary Ann Weiss
A fair amount of electronic equipment utilizes EL panels to backlight the
LCDs.

<snip>

Post by TKM
Electroluminescent panels are historically notorious for being very
sensitive to moisture so anything that damages the panel seals and allows
air or water to leak in will cause problems.

Is baking at 110C, for many hours likely to remove the water?
Or will it have chemically bound.
(assuming it's just diffusion, rather than an out-and-out failure, and
assumign that everything doesn't melt)

I would try a vacuum first. After the water is out just how do you plan on
finding the leak?
If that is the culprit.

[Clive Mitchell]

Post by TKM
Electroluminescent panels are historically notorious for being very
sensitive to moisture so anything that damages the panel seals and
allows air or water to leak in will cause problems.

Not to mention just permeating through the plastic membrane itself.

I'm not sure it is possible to bring them back by drying them out. I
think the moisture causes degradation of the material.

[Mark & Mary Ann Weiss]

Post by Clive Mitchell
Not to mention just permeating through the plastic membrane itself.
I'm not sure it is possible to bring them back by drying them out. I
think the moisture causes degradation of the material.
--
Clive Mitchell
http://www.bigclive.com

That's the thing... they are made of plastic, which is not a perfect barrier
to moisture, gases, etc.
Curiously, the particular panel that failed was in a piece of gear that
operates 24/7, in a dry studio environment. Usually, a unit that is warm
from constant operation tends to be very dry inside, inhibiting corrosion
and other moisture-related problems.
The panel was not overheated, but it was certainly operating in a warm
ambient. While moisture would be my guess, I find it hard to imagine
moisture getting into a panel in such an environment, that is, unless the
amount of moisture we're talking about can be obtained in 10% R.H.


--
Take care,

Mark & Mary Ann Weiss

VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
Hear my Kurzweil Creations at: www.dv-clips.com/theater.htm
www.basspig.com The Bass Pig's Lair
Business sites at:
www.dv-clips.com
www.mwcomms.com
www.adventuresinanimemusic.com
-

[Clive Mitchell]

Post by Mark & Mary Ann Weiss
That's the thing... they are made of plastic, which is not a perfect
barrier to moisture, gases, etc. Curiously, the particular panel that
failed was in a piece of gear that operates 24/7, in a dry studio
environment. Usually, a unit that is warm from constant operation tends
to be very dry inside, inhibiting corrosion and other moisture-related
problems. The panel was not overheated, but it was certainly operating
in a warm ambient. While moisture would be my guess, I find it hard to
imagine moisture getting into a panel in such an environment, that is,
unless the amount of moisture we're talking about can be obtained in 10% R.H.

Under those operating conditions I would say that it's just been a bad
bit of EL. Is there a risk it was being overdriven?