According to Korean website The Elec, Apple is currently in talks with Samsung and LG about applying OLED displays with two-stack tandem structures to future iPads and MacBook models. However, the devices are likely to be several years away before launch.
According to the report, a tandem structure with two stacks would have two layers of red-green-and blue emission layers. This will allow future iPad and MacBook models to display significantly brighter displays and up to twice the luminance. The report states that Apple's OLED devices, such as the iPhone, have a single stack structure.
OLED technology can be expensive so it is likely that the displays will be used in future iPad Pro and MacBook Pro models. According to the report, the future iPads will be available in 12.9-inch and 11-inch sizes. These sizes are identical to the iPad Pro sizes.
According to the report, the two-stack iPad displays are also low-power LTPO panels. This could allow for a wider ProMotion refresh rates between 10Hz and 120Hz in line with the iPhone 13 Pro models. ProMotion has been supported by iPad Pro models since 2017. However, the refresh rate is between 24Hz to 120Hz.
Timing remains a big question mark. Some reports had claimed that the first iPad with OLED displays would be released in 2022. However, the report today claims that the release date has been moved to 2023 or 2024. According to the report, though it is possible that an OLED-enabled MacBook will be released in 2025, this could be delayed.
Apple's mini-LED backlighting has been adopted by the iPad Pro (12.9 inches) and new MacBook Pro (16-inch and 14-inch models (16-inch). Mini-LED technology provides increased brightness for HDR content, and a higher contrast ratio.
Update: Nikkei Asia has released a separate report claiming that Apple is actively developing micro-LED display technology.