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Subject: Re: Extended Temperature LCD Character Module
Organization: HVW Technologies
X-Newsreader: MicroPlanet Gravity v2.30
Date: Thu, 05 Dec 2002 15:56:50 GMT
NNTP-Posting-Date: Thu, 05 Dec 2002 08:56:50 MST
In article <6ywH9.2483$RT7.email@example.com>,
> I need to switch from a normal LCD module to an extended temp range unit.
> Currently my 2X24, LED backlit, module uses a pot (0 to 5V) on the contrast
> input. It seems that the extended temperature units sometimes need a
> negative voltage and others need a voltage higher than Vcc (5V). It would
> not take to much hacking to provide a fixed, higher, contrast voltage but
> adding a temperatiure varying voltage and/or a negative voltage would be
> much more intrusive to the current design.
> Are there extended temperature LCD modules that already contain the
> temperature compensation circuitry? Or are there ones that will operate
> over the extended temp. range with a fixed, higher, contrast voltage?
> Thanks for the help.
What sort of temperatures are you talking about? My favourite answer to
this kind of a question is to look at a heater. In Canada the TAXI cab
terminals that some companies use actually have four 1W resistors
mounted just below the LCD keeping the whole thing just a little warmer.
It might seem a little crude but when you look at the expense and hassle
of so-called extended temp LCD's it balances our pretty quickly. Don't
forget LCD stands for Liquid Crystal Displays.
Maybe when the new Light Emitting Polymers become production units we
will all have a better solution.
HVW Technologies Inc.
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