What Is an LTPO Display?
LTPO stands for low-temperature polycrystalline oxide and it refers to a particular type of backplane technology seen in OLED displays. OLED stands for organic light-emitting diode, a unique type of self-emissive display found in everything from smartwatches to smartphones and larger consumer displays.
OLED displays typically use low-temperature polycrystalline silicon (LTPS) for the thin film transistors (TFTs) that make up the backplane of the display. By leveraging both LTPS and Indium Gallium Zinc Oxide (IGZO), Apple can use a combination of LTPS and LTPO technology to offer new benefits while keeping production viable.
This is all done with the aim of producing displays that can vary their refresh rate. Apple technically used this display technology in the Apple Watch Series 4, but the true benefits weren’t seen until the launch of the Apple Watch Series 5 with its always-on display.
LTPO is a breakthrough because it doesn’t require additional components between the display controller and graphical processing unit (GPU) to allow for a dynamic refresh rate.
While LTPO is an Apple-developed technology (for which it holds the patents,) Samsung has also been working on similar display technology that won’t require it to pay royalties to one of its main rivals. Samsung’s version is known as hybrid-oxide and polycrystalline silicon (HOP.)
What Benefits Does LTPO Bring?
Your smartphone’s display uses more power than any other component. While OLED screens are more efficient than their LCD counterparts, they still consume a large slice of your battery life compared to other components like the system-on-chip or wireless technologies like Wi-Fi and Bluetooth.
LTPO’s main advantage is in reducing this power consumption by varying the refresh rate. This is precisely how Apple was able to create the Apple Watch Series 5 (and its successor.) The latest Apple wearables sport always-on displays while maintaining all-day battery life.
The term “refresh rate” refers to the number of times a display updates in a second, measured by frequency in hertz (Hz). Most smartphones use 60Hz displays, though there are 120Hz models available (and Apple itself produces a “ProMotion” iPad that uses the higher refresh rate).
A higher refresh rate makes for a more responsive and smoother user experience at the cost of energy efficiency. By varying the refresh rate down to 1Hz (essentially one frame per second) as per Apple’s latest wearables, energy can be preserved since the display is making fewer requests and changes to what’s on-screen.
For example, when your phone receives a notification it lights up to notify you. During this period, there are unlikely to be any moving objects on the screen. By lowering the refresh rate the user experience isn’t compromised in any way. When you pick up your phone to check the notification, the refresh rate can be restored to a frequency better suited to general use.
This technology could be used dynamically all over the operating system. For example, if your device is displaying the “Now Playing” screen for a podcast or music, the display refresh rate can be lowered considerably. Theoretically, games that take advantage of high frame rates could “request” the use of the full 120Hz if Apple were to provide the means of doing so.
Since Apple runs a tight ship in terms of its curated user experience, the company could “enforce” more efficient refresh rates in certain circumstances like when viewing the lock screen or making a video call. Apple’s FaceID cameras can already tell when you’re looking at the screen, so it may even be possible to reduce refresh rates when the operating system sees that nobody is watching.
Which Devices Use LTPO Displays?
The first device to truly make use of the advantages LTPO brings was the Apple Watch Series 5. The smartwatch made waves when the company announced the “always-on” display technology, with a refresh rate that can go all the way down to 1Hz.
Apple has yet to fuse its LTPO wearable technology with the sort of high refresh rate display seen in the iPad Pro, but, as of March 2021, prominent leakers suggest that the company is planning on adding this technology to an iPhone in the near future.
Meanwhile, LTPO displays that use Samsung’s HOP technology are already out in the wild. These displays have been limited to flagship devices like the Samsung Galaxy Note 20 Ultra and Galaxy S21 Ultra. Anandtech’s analysis of the display used in the S21 Ultra noted “huge efficiency improvements” in terms of energy consumption.
Another Step Forward
LTPO technology presents another step forward for portable devices like smartphones and wearables. These improvements aren’t immediately noticeable in terms of visibly improved display quality, but instead, deliver efficiency gains that should help improve battery life.
How widespread LTPO displays will become remains to be seen. At present they are destined for high-end devices that make use of higher refresh rates so don’t be surprised to see them appearing in flagship iPhones and wearables before long.
Want better battery life in your iPhone without upgrading? Read our guide to improving your iPhone battery life.
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