LCD modules are made up typically of a front polarising panel, a
conductive plane with teh segment images printed on them, the liquid crystal
material, a electrically common plane, and another polarising plane and a
reflective backplane. If the display is has a two tone image, usually grey
and black with wavy edges, then it is a pretty safe bet that the liquid has
leaked out and the unit is ruined, usually impact damage causes this
failure. Sometimes due to temperature, usually too cold rather than too hot,
the display will change color over the whole of the screen, a lot of lcd
material is not freeze proof. The big advantage of lcd 's is that they use
microcosm's of power, ie millionths of an amp, or micro amps, comparitive
solid state led's use around milliamps of power, ie thousandths of an amp,
there fore the lcd modules are used for battery powered application, there
power requirements are so low that even the stray static and capacitive
charges on your fingers is enough to activate the display if touched, so the
static build up from teh commonly used plastic protective strips on teh
display is also enough to turn the segments on and sometimes keep them stuck
on, but when the unit is powered up all is well. They sometimes also
multiplex teh display, ie turn each segment on and off in turn at a rate
slighlty greater than about 30 hz, so that if something is turned on and off
more than about 30 times per second, the persistance of vision of the human
eye makes it appear to be permanntly on, which saves on more power. And if
you have ever wondered why safety gear is always yellow, its because the
peak optical response of the human eye is around 555 nano metres, ( I
think!! ), ie the colour yellow.
Chris Johnston
North RICHMOND
NSW Australia.
----- Original Message -----
From: "AVLEC" <av...@telkomsa.net>
To: "KRnet" <kr...@mylist.net>
Sent: Thursday, August 10, 2006 7:49 AM
Subject: KR> LCD problems
> Serge
> Just a short note on your LCD problem. Yesterday I bought one of those
> electronic barometers that has temp, time date, and weather forecast. When
> I
> removed it from its wrapping it had a clear protective strip stuck over
> the
> display with a fake display printed on it. As I removed this strip the
> same
> symptom appeared on the display. I at first wanted to throw the thing
> against the wall but decided to apply a bit of slight pressure to the
> display with my thumb and wala the display cleared perfectly and worked
> fine
> after that.
> Just as well I never threw it against the wall because it turns out that
> it
> didn't have a RH readout which was my primary reason for needing one of
> these things. Back it goes tomorrow!
> Regards
> Dene Collett
> KR2SRT builder
> South africa
> Whisper assembler
> See: www.whisperaircraft.com
> mailto: av...@telkomsa.net
> ----- Original Message -----
> From: "Serge VIDAL" <serge.vi...@sagem.com>
> To: <kr...@mylist.net>
> Sent: Tuesday, August 08, 2006 13:46
> Subject: KR> Drilling template for Precision Vertical Card Compass
>
>
>> I just made a printable paper template for the Precision Vertical Card
>> Compass. As usual with me, it's a Microsoft Powerpoint file. I'm not a
>> draughtsman by any account, so precision not garanteed. But it's free, so
>> anyone interested, just shoot.
>>
>> (And by the way, could anyone tell me if that compass is going to work
>> well in the Southern Hemisphere, although it is a Northern Hemisphere
>> P/N?)
>>
>> Serge Vidal
>> KR2 "Kilimanjaro Cloud"
>> Paris, France
>>
>> _______________________________________
>> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
>> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
>> please see other KRnet info at http://www.krnet.org/info.html
>>
>
>
>
> _______________________________________
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
