A brief discussion on the "high refresh rate" of mobile phone screens

Perhaps the most popular term in smartphones since last year is high refresh rate.

We have seen several mobile phone manufacturers use high refresh rate as one of their main selling points, and also vigorously use it as one of the indicators of high display quality. Refresh rate is a property of the display, measured in Hertz (Hz), and manufacturers use it to emphasize a smooth user experience. Computer screen display manufacturers have used refresh rate as a selling point for several years, but high refresh rate screens have only been used on mobile phones in the past year.

The release of the OnePlus 7 Pro made screen refresh rate a hot topic among smartphone enthusiasts and technology journalists. The device has a 90Hz OLED display, which is 50% higher than the standard 60Hz on the market at the time. Since the great success of the OnePlus 7 Pro, many smartphone companies including Samsung, Xiaomi, OPPO, Vivo, etc. have followed suit and used smoother displays in their flagship products. This year, this technology has matured rapidly, and many mid-range products are also equipped with high refresh rate screens.

In fact, as early as 2015, Sharp took the lead in launching the first high refresh rate smartphone product. However, they used an LCD screen at the time, and Sharp's mobile phone had limited influence, so the launch of this product did not cause any waves.

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What is refresh rate?

When the screen displays new content, every pixel needs to be updated. Therefore, every time the screen updates all pixels from top to bottom, it is called a "refresh", and the refresh rate refers to the frequency of screen updates or refreshes.

The typical refresh rate for most TVs, PC monitors, and smartphone displays is 60Hz. A 60Hz refresh rate means that the screen refreshes 60 times per second. As for the OnePlus 8 Pro, it has a maximum refresh rate of 120Hz, which means that the screen can refresh up to 120 times per second. As long as the screen refreshes fast enough, the human eye will feel that the content being watched is smoother.

Although our naked eyes cannot see the refreshed individual frames, we can see smooth frame sequences on the display of smartphones. When playing the same animation, the screen refreshed at 90Hz produces 50% more frames than the 60Hz display. Because of these extra frames, sliding on displays that support 90Hz, 120Hz or even higher frame rates will be smoother.

You can try different frame rates to see the difference with your naked eyes through this website.

What if the iPhone launched a high refresh rate screen?

High refresh rate is not unfamiliar to Apple fans. In 2017, Apple officially launched ProMotion dynamic frame rate adjustment technology on iPad Pro, achieving a maximum screen refresh rate of 120Hz, but Apple has not yet used this technology on iPhone. However, the smoothness of the iPhone system, that is, "hand tracking", is very good. After many years, the smooth iPhone still makes many Apple users not interested in this suddenly popular technology.

However, we are expected to witness the performance of a high refresh rate iPhone for the first time this year. It is currently reported that the iPhone 12 Pro Max will still be equipped with ProMotion technology. Compared with the LCD screen of the iPad Pro, the iPhone 12 Pro Max will have better effects than the LCD screen due to the characteristics of the OLED screen. Samsung has done statistics. For the same 90Hz screen, the OLED's smear length is about 20% shorter than that of the LCD. A shorter smear length means a smoother user experience.

If Apple implements ProMotion technology on the iPhone 12 Pro Max, we will see the smoothest iPhone ever.

High refresh rate is not useless, but it is not everything either

High refresh rate is a icing on the cake feature. A screen refresh rate higher than 60Hz can definitely provide users with a smoother user experience. But now it has slowly become an indicator of screen quality, which I think is unreasonable. A higher refresh rate does not mean better screen quality, because screen quality depends not only on the frame rate, but also on the manufacturer's calibration and optimization at the software and hardware levels. In my opinion, it is not a "feature that you can't go back to after using it."

In addition, high refresh rates often bring problems such as high power consumption, which is why Samsung, the leader in displays, has been slow to provide 2K+120Hz options for its flagship products. For this technology, I am looking forward to this year's iPhone 12 Pro Max giving a very good answer. "Doing the best" is Apple's consistent style.

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