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From: "red rover"
References: <3DE11C25.6123DC38@chariot.net.au> <email@example.com>
Subject: Re: Electroluminescent displays
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Mon, 25 Nov 2002 21:42:32 -0500
NNTP-Posting-Date: Mon, 25 Nov 2002 21:42:12 EST
Organization: Bell Sympatico
I use to design high-end EL display circuits (not backlights)
for military use. Primarily US Army helicopters (and even Air Force 1).
I have never seen visible color shift. I do recall there use
to be DC units but everything had gone AC by the mid 80s.
The AC voltage required was a trapezoid with around 210V dwell
as I recall. Brightness was
controlled by varying duty-cycle, frame-rate and voltage. You
had a choice of Green or Amber. Amber was much brighter but annoyingly
close to the filter wavelength for the Night Vision Goggles.
For low voltage battery powered DC backlights (like the Timex
Indiglo watches) I recall that one of the small IC shops made
a special chip for this. I'm pretty sure it was Sipex.
"John Fields" wrote in message
> On Mon, 25 Nov 2002 05:06:21 +1030, One Stone
> >EL displays ONLY run on AC to my knowledge. The voltage require to ecite
> >the phosphor is a function of the area.
> The voltage required to excite the phosphor depends on the intensity
> of the electric field required to pop electrons out of their
> orbitals. The area determines the _current_ required to drive the
> John Fields
> Professional circuit designer
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