Testing the USB LCD backpacks with two different character LCDs. We’ve noticed ghosting in several different brands of blue/white LCDs, have you had a similar experience?
Follow our progress in the development thread.
Thanks to IPenguin for the videos, which are GPL licensed.
Yup I bought some 16×02 white/blue lcd’s and they all have ghosting I used them in my home made mediacenter pc (driven by attiny2313 and vusb) and in power supply http://dangerousprototypes.com/2010/09/09/programmable-bench-power-supply/
Is it really ghosting or just long persistence?
The green LCD seems to have the same issue.
The term “ghosting” generally refers to a matrix driven circuit where the wrong row & column appear because of the circuit, and it happens with LED and LCD displays. The term “persistence” refers to an old image hanging around for a while until the display recovers from the previous voltage at a certain row & column.
The only way to distinguish the two is to hold a constant display image, rather than the frequently changing one in the videos. If the problem is ghosting, then it won’t disappear even after a long time. If the problem is persistence, then the unwanted image will only appear when the display is changed, and then quickly disappear.