Lumens is a Korean-based LED maker that was at CES to showcase their “microLED Display.” Their definition of a microLED is a bit different from Plessey’s, however (Plessey Shows GaN on Silicon Microdisplay). Lumens makes LEDs for the digital signage market, so a microLED for them is likely an LED less than around 1mm. A microLED for Plessey is in the tens of micron LED size range.
Nevertheless, Lumens was showing a state-of-the-art fine pitch LED display – 0.8mm. This is the finest pitch I have seen publicly. On display was supposed to be a 139” UHD resolution display using modules with this pitch. But there were some issues with the booth construction which only allowed a slightly smaller display to be assembled (photo below). This display includes a polarizer sheet and looked good, but not great. It is in need of improved image processing to create a really nice looking image. Toward that end, the company said they were working on a second generation controller.
Lumens want to sell the LED modules only, not full displays. The module is listed a 102 x 51 mm with a resolution of 128 x 64. A total of 1020 modules are needed to make a UHD wall. The company says they are a leader in creating these fine pitch modules using chip on module (or chip on board) technology.
Their manufacturing line can made for these modules now using a mass transfer technique, but it still fairly slow enabling only 20-30 UHD sets per month.
But another key technology is their ability to remove and replace defective LEDs. This machine is scheduled to be updated in the next couple of months, so we will check back on defect rates and repair rates at a later date.
The company also makes modules with 1.0, 1.2 and 1.5 mm pitches as well.
Lumens also had a demonstration of ‘monolithic’ microLEDs which we cover in Part 2.
