Smartphone displays have come a long way in a short period of time. LCD panels, which once dominated the market, have been phased out in most segments in favour of more advanced display technologies. Today, buyers can choose from AMOLED, OLED, pOLED, and other types. Meanwhile, high-end smartphones are also increasingly advertised with another term — LTPO. It is often mentioned alongside 120Hz refresh rates and always-on displays. However, LTPO is not simply another type of screen panel, but a backplane technology that helps a display dynamically adjust its refresh rate depending on what is being shown.
What is LTPO display technology?
LTPO stands for Low-Temperature Polycrystalline Oxide. It is a display backplane technology that combines two types of thin-film transistors (TFTs) — Low-Temperature Polycrystalline Silicon (LTPS) and oxide TFTs, commonly based on IGZO (Indium Gallium Zinc Oxide).
For switching circuits, LTPO uses LTPS, while oxide TFTs are leveraged for driving the display. It is this hybrid approach that allows LTPO panels to offer both fast operation and lower power consumption.
What’s also important to understand is that LTPO is technically not a replacement for OLED or AMOLED screens. Instead, it works underneath such panels by controlling the pixels. This is why smartphone specifications can refer to a screen as an LTPO AMOLED display.
The technology was originally developed by Apple as part of an LTPO backplane for the Apple Watch Series 4 in 2018. Since then, it has become increasingly common in premium smartphones and smartwatches.
LTPO Display Benefits
The biggest advantage of LTPO is power efficiency. A display running at a high refresh rate consumes more power, and not every task requires the screen to refresh that frequently. By dynamically lowering the refresh rate when possible, an LTPO display can reduce the amount of power consumed by the screen.
This is useful with always-on display features. Instead of keeping the display refreshing at 60Hz or 120Hz while showing the time, notifications, or other static information, an LTPO panel can drop to a much lower refresh rate. Some LTPO implementations can even go down to 1Hz for such use cases.
The other major benefit is that users do not have to choose between high refresh rates and power efficiency. When the content demands it, the display can increase its refresh rate. For example, while reading an ebook or looking at a static image, an LTPO display can operate at a very low refresh rate. When the user starts scrolling, it can increase the refresh rate to make movement appear smoother.
LTPO Display Drawbacks
The biggest drawback of LTPO is cost. LTPO panels are more complex to manufacture than conventional OLED displays, which is one of the key reasons they are usually restricted to high-end phones and smartwatches.
There can also be trade-offs in display density, albeit such instances are rare. One such instance is with the use of larger IGZO TFTs in LTPO, which can potentially compromise display density.
FAQs
1. What does LTPO stand for?
LTPO stands for Low-Temperature Polycrystalline Oxide. It is a display backplane technology that combines LTPS and oxide TFTs to enable more efficient control of the display.
2. Is LTPO better than AMOLED?
LTPO and AMOLED are different aspects of a display. AMOLED refers to the OLED display technology, while LTPO refers to the backplane used to control it. Therefore, an LTPO AMOLED display combines the two technologies rather than being an alternative to AMOLED.
3. Does LTPO improve battery life?
LTPO can improve power efficiency by dynamically reducing the refresh rate when high refresh rates are not required. This can be especially useful for static content and always-on displays. The actual battery-life improvement varies depending on the device and its implementation.
4. Can LTPO displays run at 1Hz?
Some LTPO displays can reduce their refresh rate to around 1Hz. This is particularly useful for static content and always-on display features, where continuously refreshing the screen at a high rate would consume unnecessary power.
5. Is LTPO only available on premium smartphones?
LTPO has traditionally been associated with high-end smartphones and smartwatches because of its higher manufacturing cost compared with standard OLED solutions. However, wider adoption and increasing production could eventually make the technology more common in less expensive devices.
