What are LTPO displays? Are they better than conventional OLEDs?

LTPO display technology is not new, but in recent months it has become popular thanks to smartphones with variable refresh rates.

LTPO stands for Low Temperature Polycrystalline Oxide and refers to a particular type of motherboard technology that is used in OLED displays. OLED displays typically use low-temperature polycrystalline silicon (LTPS) for the thin-film transistors (TFTs) that make up the display’s backplate.

Nevertheless, LTPO display technology opts for a mix of TFT LTPS and TFT oxide. The latter uses IGZO (Indium Gallium Zinc Oxide) TFTs. By leveraging both LTPS and IGZO, screens can be produced that can vary their refresh rate.

Apple technically used this display technology in the Apple Watch Series 4, but the real benefits weren’t seen until 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 allow for a dynamic refresh rate.

Even though LTPO is a technology developed by Apple (for which it owns the patents), Samsung has also been working on a similar display technology that will not force it to pay usage rights to one of its main rivals

Samsung’s version is known as hybrid oxide and polycrystalline silicon (HOP).

What advantages does LTPO bring?

The screen of your smartphone consumes more energy than any other component. Although OLED displays are more efficient than their LCD counterparts, they still consume a large part of the battery compared to other components such as the processor or communication modules.

The main advantage of LTPO consists of rreduce this energy consumption by varying the refresh rate. This is precisely how Apple has been able to create the Apple Watch Series 5 (and its successor). The latest Apple watches sport always-on displays while maintaining battery life throughout the day.

The term “refresh rate” refers to the number of times a screen is updated in one second, measured by frequency in hertz (Hz). Most smartphones use 60 Hz displays, although there are models of 90 Hz, 120 Hz, or even higher. The iPad Pro also uses uses the highest refresh rate.

A higher refresh rate makes the user experience smoother at the cost of lower energy efficiency. By reducing the refresh rate to, say, 1Hz (basically one frame per second), as in the latest Apple watches, battery can be conserved as the screen makes fewer requests and changes to what is displayed on it.

This technology can be used dynamically throughout the operating system. For example, if your device is in the music player app or in the email app, the screen refresh rate can be significantly reduced.

What devices use LTPO displays?

The first device to make use of the benefits of LTPO was the Apple Watch Series 5, with a refresh rate that can go up to 1 Hz.

Apple has yet to merge its LTPO technology for wearables with the type of tall screen it uses in iPhones, but the leaks indicate that the company is planning to add this technology in the near future.

On the other hand, LTPO displays that use Samsung’s HOP technology are already on the market. Some examples are the Samsung Galaxy Note 20 Ultra y el Galaxy S21 Ultra. Another recently announced smartphone with this screen is the OnePlus 9 Pro.

It remains to be seen how far LTPO displays will spread. At the moment, they are intended for high-end devices that use higher refresh rates.

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