NHD-0220CW-AB3 Pixel Problem

Terry

• January 28, 2020 11:44

We use the NHD-0220CW-AB3 in a number of products. One customer has noticed a variation in pixel intensity as per the attached. The modules are controlled via SPI. Is this just a faulty module or is there something else that can cause this problem? Any help appreciated.

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  ademarco

  • January 30, 2020 03:29

  Hello Terry,
  
  I had the same problem in the NHD-0420CW-AB3 (the 4 lines version) driven in I2C. There is a variation in pixel intensity.
  Please have a look to my post "Reliability problems on NHD-0420CW-AB3" and the reply I received.
  In my case it seems that the voltage used to power the display was too high.
  There are 2 operation modes: LOW voltage I/O application and 5V I/O application.
  In the first case the range is: 2,4V to 3,6V, in the second 4,4V to 5,5V.
  For I2C the datasheet says that the 5V I/O application is not supported.
  
  At which voltage did you power the display?
  How long after the problem appear (keeping the display always ON)?
  How many units have this problem?
  
  Please let me know is powering the display with a lower voltage you solve the problem.
  The point is that this check is not instant.
  In my case, the variation of pixel intensity appeared after one month of use.
  In any case, we are very far from the claimed MTBF (40.000 hours for the blue colour).
  Thanks and regards.
  
  Alberto

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  ademarco

  • January 30, 2020 03:40

  Attached another image with the same problem you have in the 4 lines version that I'm using.

  
  

  Regards.
  
  Alberto

  « Last Edit: January 30, 2020, 03:41:24 AM by ademarco »

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  Terry

  • January 31, 2020 06:27

  Hello Alberto
  
  Thank you for the replies.
  
  The display is powered from a dedicated 3.3V Supply. This the 1st time it has been seen on our products. The unit in question is with a customer & has been service for about a year, unfortunately I don't have any details of usage.
  
  Due to customer location I will probably have to send a new display to see if it corrects the issue. I will ask for the display back for investigation.
  
  Regards
  Terry

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  Alee_S

  • February 10, 2020 16:56

  Hello,
  
  Can you please share what kind of environment these displays are operating in? Is it possible they are being used in a high-humidity environment? As this could potentially explain some of the fading pixels in the current setup, and also why this issue gradually came about since its use.
  
  Best,

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