How LG Display's HMO Technology Could Extend Future Apple Watch Battery Life

The significance for Apple is clear: HMO is being considered as the direct successor to the LTPO TFT backplane currently used to drive Apple's iPhone and Apple Watch displays. LTPO's clever hybrid design, which combines fast LTPS (Low-Temperature Polycrystalline Silicon) and low-leakage oxide transistors, is the reason Apple can offer always-on displays and dynamically drop refresh rates down to 1Hz to save power . HMO aims to take that efficiency even further.

How HMO Delivers Better Power Efficiency Than LTPO

The core technical advantage of HMO is its significantly higher electron mobility—a measure of how quickly and easily electrons travel through the transistor material when an electric field is applied . In essence, a higher mobility number means the panel can drive an OLED pixel to the same brightness level with less electrical effort. Less energy is wasted as heat, and more of the battery's power is used to produce light.

Reports on the technology state that HMO is believed to let electrons flow three to five times more efficiently than current LTPO implementations. While mass-produced oxide TFTs today typically deliver electron mobility below 10 cm²/Vs, display makers are targeting around 30 to 50 cm²/Vs with advanced HMO-like materials .

This efficiency gain has several practical benefits for a device like the Apple Watch:

• Less power for the same brightness: The panel can maintain its current brightness and refresh rate while drawing less energy from the battery.
• Higher performance at the same power budget: Alternatively, Apple could push for brighter always-on screens, smoother animations at a more consistent high refresh rate, or enable more power-hungry display features without hurting battery life .

There is also a manufacturing advantage. LTPO is a complex hybrid structure that requires laser crystallization and ion implantation, a process that is roughly 30% more complex than standard LTPS . HMO reportedly avoids these costly, intricate steps, potentially making it cheaper to produce at scale while still improving the key performance metric of electron mobility .

Timeline: When Will HMO Arrive in an Apple Watch?

The most specific supply-chain reporting targets 2027 for the debut of HMO in an Apple Watch. According to Korean industry publication The Elec, LG Display plans to supply HMO-based smartwatch panels starting next year, meaning 2027 . Multiple outlets covering the report frame this as a likely feature for a 2027 Apple Watch model .

Some context complicates this timeline. A separate rumor from leaker Instant Digital suggests the Apple Watch may not receive a major external redesign until 2028 or later, possibly coinciding with the year after the iPhone's 20th anniversary . This has led to speculation that Apple might bundle a dramatic new display technology with a redesigned watch chassis in 2028 .

However, the display supply-chain intelligence and the redesign rumor are not mutually exclusive. Apple has a well-established pattern of introducing significant internal component upgrades—including new display technologies—while keeping a similar external design. The LTPO display itself debuted in the Apple Watch Series 4 in 2018 without a radical chassis overhaul . HMO could follow a similar path, arriving as a battery-life-boosting display upgrade in a 2027 model, regardless of when a full industrial-design refresh takes place.

The weight of current evidence strongly points to 2027 as the target for HMO. A 2028 timeline would more likely represent a delay or a strategic decision to pair the new display with a full redesign, rather than the current active plan.

The Supplier Rivalry: LG Display vs. Samsung Display

The development of HMO is unfolding within Apple's intensely competitive dual-supplier ecosystem. Apple historically prefers to source critical components from at least two manufacturers, a strategy that keeps pricing competitive and secures volume . For the Apple Watch, this puts LG Display and Samsung Display on a collision course over the next generation of low-power displays.

LG Display's position:

• First-mover on HMO: LG Display is the clear leader in bringing HMO to market, having already deployed the necessary equipment and begun verification on its Gen-6 line .
• Deep Apple Watch history: LG Display has been Apple's primary LTPO supplier for the Apple Watch since the technology was introduced in the Series 4, manufacturing panels using Apple's own LTPO intellectual property . HMO appears to be LG Display's own technology push rather than a licensed Apple design, which could give the company a unique advantage.

Samsung Display's position:

• Dominant in AMOLED... for iPhones: Samsung Display has long been the dominant force in AMOLED panels for Apple's iPhones, and it continues to invest billions in advanced OLED capacity .
• A different path for wearables: Samsung Display is not idly watching the HMO race from the sidelines. It is actively building pilot production lines for Micro LED smartwatch displays, an even more advanced (and currently far more expensive) technology than HMO . While current reporting does not name a specific Samsung-branded HMO competitor for wearables, the company's deep R&D in oxide TFTs and its long history of winning Apple business makes it highly likely that a competing advanced backplane solution is in development .
• The dual-source imperative: Because Apple does not want to be entirely dependent on LG Display for its watch screens, Samsung Display will almost certainly race to bring its own competitive low-power TFT solution to the table, whether it's a direct HMO equivalent or an alternative technical approach.

The real competition, then, is not just about which display technology is better in a lab. It's about which supplier can deliver the best combination of power efficiency, manufacturing yield, and sheer production volume in time for Apple's 2027 wearable product cycle. For now, LG Display has the headline technology and the head start—but Samsung Display's counter-move is almost guaranteed.