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LCD display weirdness

Started by bitrex April 7, 2016
I removed the glass LCD panel on a 16x1 display so I could peel off the 
reflective coating and install an electroluminescent backlight.

I noticed that for a while, as I touched the contacts with my fingers I 
could trigger some of the display segments to turn on briefly.

I let the panel sit for a couple hours and the effect is gone now. 
Guessing that the capacitance between the "sandwich" stored enough 
charge from when it was receiving power to power it for a bit, even 
after it was disconnected?
On 07-Apr-16 11:37 AM, bitrex wrote:
> I removed the glass LCD panel on a 16x1 display so I could peel off the > reflective coating and install an electroluminescent backlight. > > I noticed that for a while, as I touched the contacts with my fingers I > could trigger some of the display segments to turn on briefly. > > I let the panel sit for a couple hours and the effect is gone now. > Guessing that the capacitance between the "sandwich" stored enough > charge from when it was receiving power to power it for a bit, even > after it was disconnected?
I've seen the same with panels pulled fresh from storage packaging. Maybe you'd discharged yourself.
In article <cCkNy.6119$JM6.3394@fx44.iad>,
 bitrex <bitrex@de.lete.earthlink.net> wrote:

> I removed the glass LCD panel on a 16x1 display so I could peel off the > reflective coating and install an electroluminescent backlight. > > I noticed that for a while, as I touched the contacts with my fingers I > could trigger some of the display segments to turn on briefly. > > I let the panel sit for a couple hours and the effect is gone now. > Guessing that the capacitance between the "sandwich" stored enough > charge from when it was receiving power to power it for a bit, even > after it was disconnected?
It takes virtually no power to move the crystal alignment. Just moving nearby objects is enough power. That's why LCD watch batteries run for 5+ years. Overvoltage or a persistent DC voltage may get a charge stuck in the panel for a while. Give it a few hours and it will recover. -- I will not see posts from astraweb, theremailer, dizum, or google because they host Usenet flooders.
On 04/07/2016 01:20 AM, Kevin McMurtrie wrote:
> In article <cCkNy.6119$JM6.3394@fx44.iad>, > bitrex <bitrex@de.lete.earthlink.net> wrote: > >> I removed the glass LCD panel on a 16x1 display so I could peel off the >> reflective coating and install an electroluminescent backlight. >> >> I noticed that for a while, as I touched the contacts with my fingers I >> could trigger some of the display segments to turn on briefly. >> >> I let the panel sit for a couple hours and the effect is gone now. >> Guessing that the capacitance between the "sandwich" stored enough >> charge from when it was receiving power to power it for a bit, even >> after it was disconnected? > > It takes virtually no power to move the crystal alignment. Just moving > nearby objects is enough power. That's why LCD watch batteries run for > 5+ years. > > Overvoltage or a persistent DC voltage may get a charge stuck in the > panel for a while. Give it a few hours and it will recover. >
Thanks for the explanation. And I just realized I did the "ATM machine" thing with the subject of this post...
On Thu, 07 Apr 2016 05:59:34 -0400, bitrex wrote:

> On 04/07/2016 01:20 AM, Kevin McMurtrie wrote: >> In article <cCkNy.6119$JM6.3394@fx44.iad>, >> bitrex <bitrex@de.lete.earthlink.net> wrote: >> >>> I removed the glass LCD panel on a 16x1 display so I could peel off >>> the reflective coating and install an electroluminescent backlight. >>> >>> I noticed that for a while, as I touched the contacts with my fingers >>> I could trigger some of the display segments to turn on briefly. >>> >>> I let the panel sit for a couple hours and the effect is gone now. >>> Guessing that the capacitance between the "sandwich" stored enough >>> charge from when it was receiving power to power it for a bit, even >>> after it was disconnected? >> >> It takes virtually no power to move the crystal alignment. Just moving >> nearby objects is enough power. That's why LCD watch batteries run for >> 5+ years. >> >> Overvoltage or a persistent DC voltage may get a charge stuck in the >> panel for a while. Give it a few hours and it will recover. >> >> > Thanks for the explanation. And I just realized I did the "ATM machine" > thing with the subject of this post...
Well, it _was_ 01:20 AM in the morning...