Author Topic: NHD-3.12-25664UCY2 display - inconsistent pixel brightness in same areas  (Read 2701 times)


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    Using the NHD-3.12-25664UCY2  (256 x 64) using the 4-wire interface I have no problems sending full screen images and displaying them.  However all the images and patterns I send use the same grayscale value.  However, on the display some of pixels vary in their grayscale/intensity?  It's always the same pixels too.  I have tried two different displays with same results.  I would think if its noise that the pixels would be random but they are always the same. I checked the initialization sequence and it matches example in the data sheet.

    I have attached two images.  One with a picture and one with all the pixels set at the same greyscale level  (0x04).   On the image with all set to the same greyscale you can see a rectangle area at the left and right side of the LCD - but I am sending all the same greyscale values.  With the picture on some of the pixels are of different brightness/grayscale.

Please help.



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Hello Bill,

Unfortunately because these are Passive Matrix OLEDs the brightness of the pixels can vary based on how many pixels are on in a row.
The brightness will be higher if you only have a few pixels lit, as opposed to having the whole row on.


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These OLEDs are passively drawn, which means that each line is lit at once. If you have a line with almost all the pixels lit it wont be as bright as a line with only 50% or less lit up.


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