LG Display is developing a five-layer OLED panel structure that could end up in a future iMac, with an extra layer added to prevent screen burn-in and increase brightness, reports The Elec.
LG Display already builds four-stack OLED panels for high-resolution monitors, and arranges the light-emitting layers in a blue-green-blue-red pattern. The five-stack version reportedly under development adds a third blue layer, creating a blue-green-blue-red-blue arrangement.
Stacking on another emitting layer spreads the electrical load, which is important at high pixel densities, where each pixel gets smaller, as does the portion of it that actually emits light. Pushing more current through a smaller emitter to keep brightness up is also said to shorten panel life while making image retention more likely.
Apple last year sent requests for information to Samsung Display and LG Display about iMac OLED panel development. The specifications discussed were a 24-inch panel with 600 nits of brightness and 218 pixels per inch. The current 24-inch iMac's LCD manages 500 nits at the same density.
LG Display has already demonstrated a 27-inch 5K panel at 220 PPI with an RGB stripe subpixel layout. Given it uses the four-stack structure, it is likely not destined for an iMac, but The Elec suggests it is a gauge for high-density RGB stripe OLED and whether the company can manufacture it in volume.
The only problem with using five stacks, however, is cost. More emitting layers mean more organic material and a reportedly fiddlier deposition process. At the same time, LG Display has to reach Apple's brightness and lifespan requirements without ruining its yields in the process.
Samsung Display is developing QD-OLED for the same reason. Both suppliers are targeting 2028 to have the first iMac OLED panels developed, but a launch likely won't happen until 2029 at the earliest. Meanwhile, Apple is expected to refresh its current 24-inch LCD-based iMac with a new processor later this year.
