What HMO OLED Technology Is—and Why Apple Cares
High-Mobility Oxide (HMO) OLED display technology is a next-generation backplane approach that uses oxide thin-film transistors designed to deliver fast pixel switching while consuming less power and simplifying manufacturing compared with current low-temperature polycrystalline oxide (LTPO) displays, making it a promising candidate to extend Apple Watch battery life and improve future wearable display technology. Every OLED panel relies on a backplane, the grid of transistors that turns individual pixels on and off. Today’s Apple Watch and Pro iPhone models use LTPO, which combines low-temperature polycrystalline silicon (LTPS) and oxide transistors to support features like always-on displays and variable refresh rates. HMO targets the same high performance, but with a more power-efficient oxide-based design that avoids some of LTPO’s complex fabrication steps. Apple is now evaluating HMO as a potential LTPO display successor, starting with smartwatch-sized panels where gains in power efficiency translate directly into longer time between charges.
From LTPO to HMO: How the New Backplane Saves Power
LTPO displays improved Apple Watch battery life by allowing the panel to drop its refresh rate as low as 1Hz when not in active use, sharply reducing the energy needed to keep the screen on. HMO OLED display technology aims to go further by maximizing the inherent low-power behavior of oxide transistors while matching LTPO’s fast switching. Conventional oxide TFTs have struggled with low electron mobility, limiting their use in high-resolution, high-refresh-rate devices. LG Display’s HMO process is designed to raise mobility into the 30–50 cm²/Vs target range, closing the gap with LTPO while keeping power draw low. According to iClarified citing The Elec, “current mass-produced oxide TFTs typically offer a mobility rate below 10 cm²/Vs, while industry targets for next-generation applications range from 30 to 50 cm²/Vs.” If HMO meets those goals, an Apple Watch could maintain its smooth animations and always-on display while using less energy per frame.
Cheaper, Simpler Manufacturing—and What It Means for Apple
Beyond power savings, HMO is attractive because it is easier and cheaper to manufacture than LTPO on existing OLED production lines. LTPO requires complex steps such as laser crystallization and ion implantation to combine LTPS and oxide layers. Oxide-based HMO panels can skip those stages and use sputtering, a thin-film deposition technique already common in oxide processes. LG Display has reportedly installed HMO-related equipment on its Gen-6 OLED lines to develop and verify the technology, and industry reports suggest it can be adapted without rebuilding factories from scratch. For Apple, a successful LTPO display successor that uses simpler processes could improve yields, cut panel costs, and reduce supply risk. As with earlier display transitions, Apple is expected to start with LG Display for smartwatch panels and later expand to Samsung Display once the technology is proven and demand grows across more product categories.
Apple Watch as the Testbed—and a Path to Longer Battery Life
Industry observers expect the Apple Watch to be the first major wearable to adopt HMO OLED display panels if development stays on track. LG Display is currently developing and validating HMO on its sixth-generation lines for smartwatch-scale applications, with reports pointing to panel shipments beginning around 2027, though some analysts expect possible slippage to 2028. The watch is a natural testbed because its small, always-on screen makes every efficiency gain count. A more efficient backplane should extend Apple Watch battery life without needing a larger battery or a dimmer display, easing the long-standing trade-off between screen quality and endurance in wearable display technology. If Apple signs off on HMO for the watch and the technology proves reliable at scale, the same approach is widely expected to move to iPhone displays afterward, mirroring how LTPO first arrived on Apple Watch before reaching flagship phones.
