I’ve written a few times about the hardened, engineered coatings that some direct view LED manufacturers are using on their modules to better protect against damage. It’s been a little hard to explain and even harder to show in trade show photos I’ve grabbed, but this close-up comparison image does a good job.
This is from a Shenzhen LED manufacturer called Shisai Optoelectronics, and it shows a conventional fine pitch DV LED module, with its array of surface mounted light emitters, and a version beside it that uses the hardened coating.
The process is sometimes called GOB, short for Glue On Board. I’m not a fan of that term – it makes it sound like a hack instead of an engineered solution.
Shisai is one of many Chinese manufacturers that are using the process of bathing the modules in an epoxy coating that protects the fragile light emitters from dumps, scrapes, spills and static electricity.
The technical knock against these are worries like the coating picking up reflections from other lighting, overall visual quality, and concerns about the coating yellowing after months or years of trapping the heat from the light chips.
Time and experience will tell the story there, and time will also help refine the R&D outcomes. While these coatings are mostly being used by the lesser known (over here at least) companies like Shisai, Cedar and Ledman, huge brands like Samsung (The Wall), LG (Magnit) and Sony (Crystal LED) have super-premium displays marketed as microLED that also have these kinds of coatings.
For displays that are going to be up and out of the way, they’re not really needed. But displays that are at eye-level, and within reach of people, are at steady risk of accidental or intentional damage.
This video, from an unrelated company, shows how finicky repair work is one damaged LEDs.