Thanks to high refresh rate displays, many mid-range and flagship Android smartphones are significantly smoother than the standard 60Hz displays still found on most smartphones, including Apple's iPhone 12 flagship 90Hz, or smartphones that refresh at 120Hz like the Samsung Galaxy S21 and OnePlus 9 Pro, for smoother scrolling and a more immersive experience.

However, 120Hz displays can be quite power hungry, especially when operating at QHD resolutions. That is where LTPO display technology comes in.

LTPO displays allow both higher refresh rates and resolutions without turning a smartphone into a battery-eating rectangle of glass and metal. And this technology is becoming increasingly common in Android phones in 2021.

We first experienced LTPO displays on the Samsung Galaxy Note 20 Ultra. But now it is also available on all three models in the Galaxy S21 series, the Oppo Find X3 Pro, and the newly released OnePlus 9 Pro.

The iPhone 13, coming this fall, could also feature this technology, as Apple looks to rival major Android phones with this popular feature.

Here is what you need to know about LTPO and how it will work on some of the best phones this year.

LTPO is an acronym that stands for low-temperature Polycrystalline Oxide. In short, it allows the display to dynamically change its refresh rate without requiring additional hardware components located between the device's graphics processing unit and the display controller.

By allowing the refresh rate of the display to change on the fly, the device can switch from using a higher refresh rate, which consumes more power, to using a lower refresh rate when not needed, thus drawing more battery life.

Apple has developed a new technology called "Apple's Refresh Rate".

Apple has developed LTPO technology and used it in the Apple Watch Series 5 to reduce the refresh rate from 60 Hz to 1 Hz, making the smartwatch last longer. Therefore, such technology can be used in smartphone displays to reduce power consumption.

Many OLED displays in cell phones currently use low-temperature polycrystalline silicon (LTPS) in the thin-film transistor (TFT) structure that forms the display's backplane, which essentially supplies many of the electronic components that make the display work LTPS use has made OLED displays in smartphones about 20% to 30% more power efficient than IPS LCD displays.

However, LTPS panels do not allow for dynamic refresh rates without extra hardware, as in the OnePlus 8 Pro and Oppo Find X2 Pro. In addition, other models can only switch between 120Hz and 60Hz, and do not support anything below the middle of that range.

Display back panels using LTPO, on the other hand, combine LTPS TFTs with transistors made of indium gallium zinc oxide (IGZO). The result is a display back panel in which the IGZO TFT is used to drive the display and the LTPS TFT takes care of the switching circuitry. This improves the overall efficiency of the display and allows the refresh rate to be changed dynamically.

All of this sounds very promising for future phones, but have you noticed that phones like the iPhone 12 Pro do not support LTPO displays? Apple does not even have a 120 Hz smartphone display yet, but that is rumored to change with future iPhones.

This is because IGZO TFTs are larger than their LTPS counterparts and cannot be packed so densely into a display. In such displays, the use of IGZO transistors would result in a loss of screen sharpness, since a TFT is used for each pixel.

However, in the latest Android flagships, companies like Samsung and Oppo have found ways to use this technology without compromising screen sharpness.

Since the LTPO patent is owned by Apple, Samsung worked on its own display technology that mimics LTPO. The technology in question is HOP.

Short for Hybrid-oxide and Polycrystalline silicon, HOP effectively combines LTPO technology with oxide TFT. And the LTPO technology was incorporated in the Galaxy Note 20.

But with the Galaxy S21, Samsung pushed the limits of displays even further, and Samsung Display developed an LTPO panel that can reduce the power consumption of an OLED display by 16%. However, a review of the Samsung Galaxy S21 Ultra shows superb battery life while powering a 6.8-inch screen with a resolution of 3200 x 1400 and a peak brightness of 1300 nits.

A new addition to the LTPO mix, the OnePlus 9 Pro seems to have found the right balance between a fast refresh display that adjusts on the fly and good battery life. When we tested OnePlus' new flagship with Dynamic Display enabled, it lasted 10 hours and 40 minutes in our grueling battery test. This is well above the smartphone average and just about ranks on our list of best smartphone battery life. Even better, setting the phone's display to 60 Hz had no effect on battery life at all.

And here's the good news, as Samsung Display manufactures OLED screens for Apple and is expected to continue to do so for the iPhone 13.

Given that Apple has yet to adopt a high refresh rate display, the move to LTPO panels will jump ahead of the displays seen in late 2019 and 2020 phones and provide the iPhone 13 with a display suitable for 2021, which would make it possible to.