What is an LTPO display?
LTPO stands for low temperature polycrystalline oxide and refers to a particular type of backplane technology seen in OLED displays. OLED stands for Organic Light Emitting Diode, a unique type of self-emitting display that can be found everywhere from smartwatches to smartphones and larger consumer displays.
OLED screens typically use low-temperature polycrystalline silicon (LTPS) for the thin film transistors (TFTs) that make up the display’s back plate. By leveraging both LTPS and Indium Gallium Zinc Oxide (IGZO), Apple can use a combination of LTPS and LTPO technology to provide new benefits while keeping production viable.
All this 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 real benefits only became apparent with the launch of the Apple Watch Series 5 with its always-on display.
LTPO is a breakthrough because it does not require additional components between the display controller and the graphics processing unit (GPU) to enable a dynamic refresh rate.
While LTPO is a technology developed by Apple (for which it owns the patents), Samsung has also been working on similar display technology that does not require it to pay any royalties to any of its main rivals. Samsung’s version is known as hybrid oxide and polycrystalline silicon (HOP.)
What are the benefits of LTPO?
Your smartphone screen consumes more power than any other component. While OLED screens are more efficient than their LCD counterparts, they still consume a great deal of your battery life compared to other components such as the system-on-chip or wireless technologies such as Wi-Fi and Bluetooth.
The main benefit of LTPO is to reduce this power consumption by varying the refresh rate. This is exactly how Apple was able to create the Apple Watch Series 5 (and its successor). Apple’s latest wearables have always-on displays while the battery lasts all day.
The term “refresh rate” refers to the number of times a display is updated in one second, measured as a frequency in hertz (Hz). Most smartphones use 60Hz screens, although 120Hz models are available (and Apple itself produces a “ProMotion” iPad that uses the higher refresh rate).
A higher refresh rate provides a more responsive and smoother user experience at the expense of energy efficiency. Varying the refresh rate to 1 Hz (essentially one frame per second) according to Apple’s latest wearables can conserve energy as the screen makes fewer requests and makes fewer changes to what is displayed on the screen.
For example, if your phone receives a notification, it lights up to notify you. During this time, moving objects are unlikely to appear on the screen. Lowering the refresh rate does not affect the user experience in any way. When you pick up your phone to check the notification, the refresh rate can be restored to a frequency more suitable for general use.
This technology can be used dynamically throughout the operating system. For example, if your device is displaying the “Now Playing” screen for a podcast or music, the screen refresh rate may be significantly reduced. Theoretically, games that take advantage of high frame rates could “demand” the use of the full 120Hz if Apple provided the means to do so.
Since Apple has a tight ship in terms of composite user experience, the company could “enforce” more efficient refresh rates in certain circumstances, such as when viewing the lock screen or making a video call. Apple’s FaceID cameras can already see when you look at the screen, so it may even be possible to lower the refresh rates if the operating system sees that no one is looking.
Which devices use LTPO screens?
The first device to really take advantage of the benefits of LTPO was the Apple Watch Series 5. The smartwatch caused a furore when the company announced its “always-on” display technology, with a refresh rate that can drop all the way down to 1 Hz.
Apple has yet to combine its wearable LTPO technology with the kind of high-refresh rate display seen in the iPad Pro, but as of March 2021, prominent speakers suggest the company plans to add this technology to an iPhone in the near future. to add.
Meanwhile, LTPO screens using Samsung’s HOP technology are already in the wild. These screens are limited to flagship devices such as the Samsung Galaxy Note 20 Ultra and Galaxy S21 Ultra. Anandtech’s analysis of the display used in the S21 Ultra pointed to “massive efficiency gains” in terms of power consumption.
One more step forward
LTPO technology represents a new step forward for wearable devices such as smartphones and wearables. These improvements are not 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. Currently they’re for high-end devices that use faster refresh rates, so don’t be surprised to see them appear in flagship iPhones and wearables soon.
Want better battery life on your iPhone without upgrading? Read our guide to improving your iPhone battery life.
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