USB LCD backpack display trials
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.
This entry was posted in LCD, testing and tagged FT232, test.
Comments
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.