As I understand it that display is a passive matrix, not TFT, so there is inevitably some level of interference between pixels.
Post a picture of what you see on it - others may then be able to decide if that's normal or erroneous?
Thanks for your comment. I appreciate that the 5110 is pretty old, we have three 5110 phones in service - the best phone ever. I guess you are right, and Nokia may keep the screen clean by careful control and careful choice of what to show. The streaks appear to vary. There is virtually nothing there right now and it is very hard to photograph. There may even be some optical illusion in this, the van der Biezold effect perhaps. The main problem is in the graph bar, about ten pixels in from each end. Looking through a loupe, I can't see any streaking but I can now see that the pixels in question at the right are actually faulty. They are not so bad individually at the left, but the cumulative effect is worse. You can see, though, that the bad patches in the bar align with the gaps between the characters above, so maybe there is more than one problem in play.
I have three little sketches, clock ( badly streaked), graphics (rather washed out), and text (excellent). I copied the initialisation from the text to the others. The clock was a lot better but it did nothing for the graphics.
LcdWrite(LCD_CMD, 0x21); // LCD Extended Commands.
LcdWrite(LCD_CMD, 0xBf); // Set LCD Vop (Contrast). //B1
LcdWrite(LCD_CMD, 0x04); // Set Temp coefficent. //0x04
LcdWrite(LCD_CMD, 0x14); // LCD bias mode 1:48. //0x13
LcdWrite(LCD_CMD, 0x0C); // LCD in normal mode. 0x0d for inverse
I would like to better understand the contrast, and bias. Perhaps there is not much there to understand. Even Lang's magnum opus has nothing to say.http://ianlangelectronic.webeden.co.uk/#/lcd-module-0/4569058582
Here is the clock. The text seems fine. I'm pretty pleased with that.