OnePlus 9 Pro Display Features In-Depth: Story Behind 1Hz LTPO Display and Making New Standard, New Track

So when the 9 Pro project was set up, we insisted that we must not play the game with power consumption as painful as the 8 Pro, and we must have a breakthrough in this area of power-saving, and at this time the pre-research group came to us with the LTPO technology roadmap.

LTPO is very simple, that is, the OLED screen refresh rate can be reduced to below 60Hz, and can change the refresh rate per frame, while the ordinary previous generation LTPS screen, only a few fixed gear refresh rates can be selected because in many cases we browse the content, the frame rate is actually much less than 120Hz, or even below 60Hz, LTPO can be a very good match to the frame rate of the content, and dynamically reduce the power consumption of the screen.

To be honest, although we all know that LTPO has a great potential to gain in power consumption and is the technology we dream of, no one knows how to use it and there is no previous path to follow, which also means great technical risk and uncertainty.

We could not see any samples or demos at the time of the project, LTPO was only on the PPT, no one knew what would happen if this was finalized, even other brands, when they were ready to go on LTPO, they all prepared the same specifications of the ordinary screen as a backup, once LTPO problems ready to switch the spare tire, we faced a difficult choice can be imagined.

But we are not always the first to eat crabs, the first 2K90, the first 2K120, we have done too many difficult things in the past two years, I remember as if acid digital said a sentence when he does not see the difficulties in the project, the project is likely to face failure. So we were shooting, facing the future, continue to lead the industry to the next key technology node, not to mention the pre-research group with the characteristics of LTPO, but also achieved a very impressive thing, this first press not a table.

By the time we got the screen samples in September, we spent a lot of time communicating with Samsung, the technical details of LTPO, what is the mechanism of screen frequency conversion, how we want to control it, after all, after understanding these, we can better define the upper control strategy, this time I was under a lot of pressure, on the one hand, if the strategy was not well defined, once it involved major changes and modifications, the development architecture might have to be reconstructed, and the very tight project schedule might be further aggravated, and on the other hand, the Cyberpunk Custom Edition was at a critical closing stage, with OS acceptance, accessories, packaging, and marketing things coming up, making me a bit distracted.

Thanks to the help and guidance of the technical leader of the project, we quickly figured out the frequency conversion mechanism of the screen, and the upper layer of the strategy, after I took a shower, the light came on (by mistake, the combination of LTPO’s technical advantages, overlaid with some of our mature means on the 8 Pro, we quickly finalized the overall strategic framework, and there are no major changes to date.

As mentioned earlier, the initial upper layer strategy is defined, but the development workload is still much more than expected, I will give an example, ordinary LTPS screen, want to make the screen bright need to configure 60120 two groups of parameters, if you count the special 30Hz AOD that is three groups of parameters, each group of parameters need to be completed when the upper layer needs to switch, such as the horizontal screen to watch the video.

For example, when watching a video in landscape, the refresh rate should be cut from 120 to 60; when the phone locks, the screen should enter AOD mode from normal mode, these changes in the bottom of the screen are not perceived by ordinary users, only then can the experience be seamless and smooth.

But here at LTPO, this driver parameter has become an amazing 24 groups! I laughed when I first saw it, we can develop this to handle it, each group is not just light up the screen on the line, because the upper and lower linkage will have a very complex inter-cut logic, but this is not optional, but a must reach the item, only these frequencies are through, we can maximize the use of this screen inverter capabilities, to bring down the power consumption.

Samsung to provide screen specifications, to treat the same, only willing to ensure that the frequency effect of 10-120Hz, but with our understanding of the Samsung screen settings, after repeated exploration and experimentation, we successfully made a refresh rate of 1Hz, and to achieve a smooth frequency of 1-120Hz, so that the power consumption of the screen can be reduced to lower, we have done a lot of effect testing and aging tests to ensure that our frequency effect is always the same, the user can not perceive.

Well a bit more nonsense, the following talk about our specific scheduling strategy. In your daily use of cell phones, as long as the finger is touching the screen, the screen always responds with the highest refresh rate, so you can not feel the lag or fluency brought about by the frequency reduction, only when the screen is still, the screen refresh rate will immediately drop to the lowest refresh rate, to achieve the purpose of power-saving.

Some people may ask, that does not sound like much savings ah, in fact, not, we look at the big data, the user every two touches between the pause time added up, in fact, very significant, which is also in line with the use of intuition, who is looking at the WeChat public, read the melon of interest, but also must stop to look carefully at what is written ah

This is how we have achieved the same or even lower power consumption than the previous generation of 60Hz for 120Hz daily browsing and sliding scenes.

Next, we wondered what other scenarios are a serious mismatch between the input frame rate and the output refresh rate, and finally found that one is video, one is navigation, we still see most of the video today is 30 fps or 24 fps, we use this screen to do, 24-60Hz adaptive follow the video frame rate, the same in the navigation scene, once we identify the phone in navigation mode, the screen can reach a minimum refresh rate of 30Hz to follow the navigation of the lower position update frequency.

Overall, we did not let the user lose the smooth and senseless experience because the screen has the ability to downscale, it is still the performance scheduling you are familiar with, or silky smooth 120Hz, or elegant full-screen gestures, or light sliding curve, and thanks to the refresh rate can be intelligently adjusted, we have made up for some of the regrets of the previous generation, for example, in the video application we did not lock 60Hz this time, only when the full screen is recognized to play video, it will enter 24-60Hz adaptive mode.

I think this is the only way to meet the LTPO of OnePlus, and dare to say that they are the new standard of the whole industry screen. I have a very strong feeling that everyone will eventually see the value of LTPO, and it’s only a matter of time before this technology is popularized in flagships.

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