EV: In its MicroLED Displays 2018 report, Yole highlighted the challenges of driving microLEDs, especially with traditional TFT backplanes such as LTPS or Oxide (Yole will also discuss the topic at the upcoming SID –Display Week Conference in San Jose in May). glō seems to have made significant breakthroughs in that regard. How are you addressing the challenge of microLED non-linearity? What kind of compensation circuits might be needed and how do they differ from other emissive technologies such as OLEDs?
FD & AN: The standard compensation circuitry needed for OLED LTPS and CMOS uniformity are suitable for glō’s LEDs. There are two attributes in glō’s technology that allow us to use standard LTPS driver electronics and compensation:
- glō microLEDs are specifically designed to be efficient in the low current regimes offered by LTPS and CMOS back planes.
- All colors of glō microLEDs, including red, are made with InGaN material, simplifying the demands on compensation circuits. The InGaN semiconductor material also has the advantage of longer life times and better temperature stability, reducing the burden on compensation circuitry.
EV: What kind of brightness levels can be achieved with glō microLED displays on CMOS vs LTPS backplanes? Can they both deliver a wide dynamic range?
FD & AN: To date glō has been able to achieve 4,000 nits from LTPS backplanes and up to 150,000 nits from CMOS backplanes. Both CMOS and LTPS backplanes offer the ability to turn off a pixel completely while the adjacent pixel is fully bright. This enables true high dynamic range (HDR) displays, i.e., the achievable brightness difference between adjacent pixels is orders of magnitude better than OLED.