Affect of -40C temperatures on a LCD display

[nobb]

Hey.

I have a carpc and I am looking to get a new LCD screen because my current one does not operate in -40C temperatures. I was hoping someone more technical than me might be able to answer some questions I have on LCD screens and operating them in low temperatures. I am interested in this screen:

http://linitx.com/viewproduct.php?prodid=10949

Its minimum operating temperature is -20C, but I am wondering if I can operate it at even lower temperatures (and the possible negative effects). Some users have reported that their LCD screens (other models) have worked in even lower temperatures. What sort of negative effects do such low temperatures have on these screens? I have read that the CCFL backlights used in these screens have shorter lifespan if operated at such low temperatures. Can someone confirm? What about the actual LCD screen itself? Is there a possibility that the freezing of these liquid crystals might crack the screen (like frozen water cracking stone)?

How do car manufacturers with OEM LCD screens integrated into the vehicles deal with these temperature extremes? Maybe someone can provide a "highly technical" answer to these questions.

 

[dkozloski]

I'm in Fairbanks , Alaska. Every gas pump in town has an LCD screen for the card reader and they all seem to work fine down to -50F at least. I had a Cadillac CTS with an LCD digital information center and it worked fine to -50F and colder. The worst I've seen happen is that am LCD screen goes dark but as soon as it's warmed up it works fine. From experience I would say this is a non-problem.

 

[f95toli]

LCD screens CAN crack,although usually they just stop working at low temperatures; i.. the screen goes blank but when you warm it up it starts working again. THis can be a major problem with e.g. cameras during the winter.

There is a very physical reason for this. Liquid crystals go through a lot of different phase transitions as you change the temperature (it can litteraly be tens of transitions over even a small temperature range) and only some of these phases work in displays (i.e. change the polarization of the light that passes through them).
Now, for displays they do of course use crystals trhat have as few transisitions as possible, but nevernthless they DO go through a transition when you cool (or heat) them enough.


edit: I forgot to mention something. There is a very simple "critical temperature" for electronics which is set by the fact that it is often transported by air in cargo planes (where the temperature can drop to low temperatures). Hence, almost all commercial electronic devices are made to "survive" those temperature(which does ot neccesarily mean that they can be operated at this temperature) without problems. This temperature is sometime listed in "real" datasheet.
I know of at least one type of LCD display that failed commercially for this reason. It was sold in Japan but it was too expensive (this was 15 years ago) to export (it was fragile due to the type of crystal used, not because of the backlighting).

 

[nobb]

It seems to me that the dimming problem that LCD screens experiences is probably due to the properties of CCFL tubes. I did some reading and it appears that the striking voltage (required to ionize the gases in the tube to make it glow) increases almost exponentially the lower the temperature. I have also read that operating the CCFL tubes at low temperatures reduces their lifespan. Does anyone know why this is?

So right now, I am hoping to find a 7inch touchscreen monitor which has a LED backlight.