LTPO, short for Low-Temperature Polycrystalline Oxide, is a type of display backplane technology that lets your screen dynamically shift its refresh rate, dropping as low as 1Hz for static content and ramping up to 120Hz or higher for fast motion. This is the technology behind features like always-on displays and adaptive smooth scrolling on modern smartphones and smartwatches. It works by combining two different types of transistors on a single panel, each optimized for a different job.
How LTPO Combines Two Transistor Types
Traditional OLED screens use one type of transistor material in their backplane, the circuit layer that controls each pixel. LTPO panels use two. The first is LTPS (low-temperature polycrystalline silicon), which moves electrical current quickly and excels at driving pixels at high refresh rates like 120Hz. The second is an oxide transistor, typically made from indium gallium zinc oxide (IGZO), which has an extremely low “leakage current.” That means when pixels need to hold a steady image, the oxide transistors barely sip any power.
By putting both materials on the same backplane, an LTPO display gets the best of both worlds. The LTPS transistors handle the heavy lifting when you’re scrolling, gaming, or watching video. The oxide transistors take over when the screen is showing something static, like a clock face, a photo, or a page of text you’re reading. The display’s controller decides which refresh rate to use moment by moment, shifting seamlessly between them based on what’s happening on screen.
Why Variable Refresh Rate Matters
A standard 120Hz OLED redraws the entire screen 120 times every second regardless of whether anything on screen is actually changing. That’s a lot of unnecessary work when you’re staring at a notification or reading an article. An LTPO display can drop to 1Hz in those moments, updating just once per second, and the savings add up quickly over a full day of use.
The transition isn’t just between 1Hz and 120Hz. LTPO panels can settle at intermediate rates like 10Hz, 24Hz, 30Hz, or 60Hz depending on the content. A 24fps video, for instance, doesn’t need a 120Hz refresh. The display matches the frame rate to the content, trimming power consumption at every step without any visible difference to you.
How It Enables Always-On Displays
Always-on display (AOD) is one of the most visible benefits of LTPO. When your phone is locked, the screen can show the time, notifications, and widgets while refreshing at just 1Hz. At that rate, the oxide transistors hold the pixel voltage steady with almost no current draw, so the feature costs very little battery life. Before LTPO, always-on displays were either unavailable on high-refresh-rate screens or came with a noticeable hit to battery longevity. LTPO made it practical to keep useful information visible around the clock.
LTPO vs. Standard LTPS Displays
Older OLED panels built entirely on LTPS backplanes are fast and bright, but they can only run at fixed refresh rates, typically 60Hz or 120Hz. Some can switch between those two settings, but they can’t scale smoothly across a wide range. LTPS transistors alone leak too much current at low refresh rates, which causes image quality issues and wastes power when holding a static frame.
LTPO solves this by assigning the low-refresh-rate duty to oxide transistors, whose off-state leakage is orders of magnitude lower. The result is a panel that matches LTPS in peak smoothness and responsiveness (both still use OLED emitters with sub-1ms response times) while consuming significantly less power across a typical day of mixed use. The tradeoff is manufacturing complexity: producing a hybrid backplane with two transistor materials in one fabrication pass is harder and more expensive, which is why LTPO has historically appeared only in premium devices.
Who Developed It
Apple filed foundational patents for combining silicon and oxide transistors on a single display as early as 2013, with a formal application in April 2014 covering displays that use both material types in their driver circuitry. Samsung Display developed its own implementation and has been one of the primary manufacturers of LTPO OLED panels for both its own Galaxy devices and other brands. The technology first appeared in smartwatches, where battery efficiency is critical, before scaling up to smartphones and tablets.
Which Devices Use LTPO
LTPO is now standard in flagship smartphones and increasingly common in foldables and tablets. Apple’s iPhone Pro models and Apple Watch use LTPO panels. Samsung’s Galaxy S Ultra and Galaxy Z Fold lines rely on them. Beyond those two, the technology has spread widely: Huawei’s Mate 70 lineup features LTPO AMOLED screens reaching up to 3,500 nits of brightness, and its Mate X6 foldable uses LTPO panels on both its inner and outer displays. Google’s Pixel Pro phones, OnePlus flagships, and several other premium Android devices also use LTPO.
Mid-range phones still typically use fixed-rate LTPS OLED or LCD panels. If a phone’s spec sheet mentions an adaptive refresh rate ranging from 1Hz to 120Hz, it almost certainly has an LTPO backplane. A phone that lists only “120Hz” without a low-end range is likely using a standard LTPS panel that stays locked at that rate or toggles between 60Hz and 120Hz.
Generational Improvements
Manufacturers label newer versions as LTPO 2.0, 3.0, and so on, though these aren’t standardized industry terms. Each generation generally improves how quickly the display transitions between refresh rates, how efficiently the oxide transistors hold voltage at low rates, and how much power the panel consumes at peak brightness. Earlier LTPO panels sometimes showed slight flicker or lag when shifting rates; newer generations handle those transitions more smoothly, making the adaptive behavior invisible to the user. Brighter peak output and better efficiency at high brightness have also improved with each revision, which is part of why modern LTPO flagships can hit 2,500 to 3,500 nits while still lasting a full day on a charge.