speaking of displays & DPM

[Wayne Braun]

At 08:32 AM 8/26/96 -0700, you wrote:
>Maybe I have an odd LCD pannel (2x20, I doubt it). Mine turns black when the
>car warms up in the sun.

        I don't know if the new, fancy, latest technology displays do this
but this is typical of some of the standard alpha-numeric displays.

        In a previous life, I worked at a company that used LCD displays.
The first time that the guys ran into this it caused quite a bit of
consternation. They were calibrating an instrument outside during the summer
and it was about +30C. They thought that they had destroyed the unit. As it
turned out, all that was needed was to let things cool down and the
everything was fine.

>
>At 08:23 AM 8/26/96 -0500, you wrote:
>>>LCD displays also don't work very well when they are hot.  All the crystals
>>>polarize.  There are a number of LCD video projectors and they have to be
>>>chock full of fans to keep the LCD cool enough to remain useful.
>>>
>>
>>No, LCD displays don't work well when they're cold.  The temp extremes
>>inside a car is fine for LCD -- except very cold days.
>>
>>tom cloud

        I guess this would depend on where you are. If you are in a place
like England where you typically don't see extreme temperatures then you
could be OK. Here on the other hand we see temperatures ranging from +40c in
the summer down to -50c in winter. We don't always see these extremes (
except for last winter ) but you do need to account for them. Unheated LCD's
tend to get a little slow at -40.

        For general testing purposes, you will likely run into very few
problems but if you are going to permanently mount this you should look for
one that is designed for use in this environment.

        Regards
        Wayne Braun