T41-3 Part 4 A Few Notes on Displays and Radio Frequency Interference

A few random notes on RFI and displays. I found this interesting display on eBay:

https://www.ebay.com/itm/388858163988

It’s interesting due to the metal shield added to the back side of the module. Note how the shield has a tab from the shield to the PCB, right next to the connector. I assume it touches a ground land on the PCB, perhaps even gold plated. This could be a feature to help reduce radiation from the display, or to prevent the display from being RFIed from external sources. Perhaps this display is intended for automotive applications?

The displays from Riverdi are claimed to be low radiation. Here is what they say:

Low EMI design STM32 Embedded boards were designed with special attention paid to electromagnetic compatibility, a design that has given them a high immunity to external electromagnetic signals which otherwise could have disturbing influence on their working correctly.

Board is equipped with low noise backlight converters thanks to which they produce low electromagnetic interference (EMI) to the surrounding space. In consequence, external electronic devices or circuits do not need special electromagnetic screening.

The EMC measurements held in a specialized laboratory confirmed low electromagnetic emissions of STM32 Embedded modules, even when displaying dynamic pictures.

I have ordered a Riverdi display module and try to compare it to an RA8857. Here is what Riverdi claims about their modules with respect to RFI:

https://youtu.be/4MZhAJaRzpI?t=293

I reckon the only way to find out how well they perform with respect to RFI is to put one in an radio and test it.

– 73 Greg KF5N