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LCD screen works from touch? Answered

I was taking apart a small department store card reader and as i was doing so i noticed that the LCD screen would kinda  work from my fingers touching it.  Some parts of numbers and indicators glowed as I ran my fingers across it.  Is this from static electricity is my hands?  Or just residual power in the display.   All wires were removed from it so no capacitors to power it or anything.  I did notice that the silicon-rubber-carbon? thing on the top and bottom of it were attached.  Can someone with a knowledge of how these displays work please explain this phenomenon.


2 Replies

Downunder35m (author)2017-05-23

Pressure ;)
Was already the same with the first LCD (numeric) displays.
That is one reason why modern screens are so stiff and usually covered with a rigid glass "plate".
You can try the same on your flatscreen tv, when it is running slight pressure on the screen will change the colors - don't press hard!!!

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