NHD-1.5-128128UGC3 Graphic Display Ghosting
Hi there,
I'm using an NHD-1.5-128128UGC3 Display (128 x 128 pixels RGB Oled ) module.
The display content is controlled via SPI at a rate of approximately 10Hz (1 Image sent every 100ms, SPI rate is more around 5Mbs).
The Display is working fine , but there seem to be some kind of Ghosting /tearing on the screen when displaying some kind of figures on it.
If i display an horizontal line on the display, that covers for example 75% of the width, the left pixels are illuminated more ( or less depending if the background is white or black and the line is of opposite color ). I interpret it as this line guetting roughtly the same amount of power as other lines , but this power is divided between less pixels as many are truned off ( since a draw a black line).
Thus the other lines , have to share the power between more pixels, and thus seem less illuminated ( i'm just trying to explain the effect i'm witnessing with simple words)
I'am powering the board through a stm32 nucleo ( in 3,3VDC), but i also tried powering it from a lab power supply to make sure it wasn't a current problem with the max current capabilities of the nucleo board, but it made no change.
Is there anything that can be done to improve the rendering of the display in order to make those lines:
- could i overcome the problem by tuning internal settings of the ssd1351 drivers ( VCOM, frequency,... ) ?
- should I avoid to wide color difference between pixels on a same line '?
Many thanks in advance for the help
Eric
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Hi Eric,
Your interpretation is correct about each horizontal line's pixels sharing the current through each pixel within the line.
This does effect the overall brightness of the pixels within each horizontal line and will result in the brighter pixels appearing next to the long black line where most of the pixels are off.
Some ideas to reduce this effect would be to reverse the image so the background pixels are off and only the bar graph and other graphics are lit.
Reducing the display contrast will also reduce the trails but this will affect the brightness of the overall image.
Using a color background vs a white background will also reduce the visibility of the bright pixel trails as the contrast difference using color pixels will not be as wide as the black and white image.
Regards,
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