protecting NHD-1.8-128160EF-CTXI# from ESDs on a battery powered application

tsmrnd

• May 29, 2019 20:49

Hi,
I'm currently working on a battery powered device that must comply with IEC60601-1-2 4th edition.
At the moment being, I am a having problems with the ESD test.
Everything was fine until the zap gun was pointed at the screen.
The display is protected with acrylic of 0.5mm thickness. There is an air gap of 1.5mm between the display and the acrylic.
The zap gun was configured for 15KV and it was applied at a distance of about 4mm from the acrylic.

After the ESD, the power consumption of the display and its brightness increased.
The application cannot be seen clearly because of too much brightness.
I guess the display got damaged.
The same happened to the other device under testing.

Will adding some vessels (made of a copper fold) to the display help protecting it from ESD?
What else can be done to prevent the ESD from going into the display panel?

Any advice will be appreciated.

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  gsubas

  • July 19, 2019 15:37

  Hello tsmrnd,
  I am running into similar situation. Were you able to resolve the issue? If yes, could you point me to the right direction?
  
  Thank you.
  
  Regards.

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  Sergio_M

  • December 31, 2019 11:33

  Hello,
  
  The following techniques can be used to improve ESD shielding for our displays.
  One or more options may be suitable depending on your application.
  - Add a TVS diode between VDD and GND
  - Tie the display's bezel to ground 
  - Add ~33-ohm resistors on the data and clock lines
  
  Hope this helps!
  

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  DavePo

  • November 16, 2021 14:07

  Hello.
  Did any of these suggestions eliminate the ESD issue ?
  If so, which one ?
  If not, what other techniques were tried until success ?
  

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  Ted M.

  NHD Staff

  • November 22, 2021 09:22

  Hi DavePo,
  
  This display is rated to withstand an 8kV Air spike and 4kV Contact spike without damage to the display.
  Depending on your application and product environment, all of the options mentioned previously to control ESD should be considered in your design.
  If your application is critical to prevent interruption due to ESD, then adding a periodic display reset in the application code will help to recover from most lockups that could occur after an ESD event.
  
  Otherwise, adding an extra air gap between the front bezel glass and the display surface will help to prevent an ESD spike from affecting the operation of the TFT.
  
  Regards,

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