LCD Problem

[GuitarDude]

Hail all.

See the LCD (with elastomeric connectors) of the transparent device on this video:

https://youtu.be/KXjBXFq_sTQ

Does anyone know the name of this sort of "bleeding" problem, its cause and its solution?

Much grateful for all your help.

[GuitarDude]

No one knows then?

[jpanhalt]

Watched most of the video.  It's a bit hard to see exactly the problem.  Some of what's shown looks like the contrast is set too high.  Some may be failure to erase properly.  When I erase an LCD, I print every pixel with a 0.  There are possibly other causes.

Can you post a picture of your LCD to clarify exactly what the problem is?

[GuitarDude]

Thank you for answering.

There is also this video (none of these videos are mine):

https://youtu.be/Dd9XnJT687s

But that first video already has an immediate comparison. In its first 15 seconds the problem can be seen. The brown device has the pixels right, as they should be, with clear figures on screen. The transparent device has all its pixel figures with shadows (half lit pixels?). Its owner speaks about this fault at 1m13s...and says that the LCD was changed, but it did not correct it... Could this then by some fault on the circuit board? Any guess where?

[jpanhalt]

A pixel on an LCD screen stays on until it is turned off.  Turning it off requires sufficient voltage.  Turning it on is the same.  Contrast as well as the Ve (negative voltage) supply and perhaps time (i.e., interface speed) controls both.  I have never had the problem you see; however, I have had the problem of insufficient "boost voltage" result in dim images.  Changing my "boost" fixed it.  That was a firmware change.  I don't have a clue about what you can control with your device.  Nevertheless, I suspect it is firmware and not a defect in your screen.

EDIT:  You might find this video by fearless Dave helpful: https://www.eevblog.com/forum/blog/eevblog-1045-how-to-drive-an-lcd/msg1371450/#msg1371450