Honor 50 Series’ 1920Hz High-frequency PWM Dimming
Not long ago Honor launched a new generation of digital series, Honor 50 Series, its screen using the 1920Hz high-frequency PWM dimming while solving the problem of DC dimming and low-frequency PWM dimming strobe stimulation, so we see a new possibility of OLED screen dimming, let us today to understand in depth what exactly is high-frequency PWM dimming.
For OELD screen, the eye protection function is also a lot of consumers are exceptionally concerned about the place, because long time use of cell phones, then easy visual fatigue, and even affect eye health, Honor 50 series screen through the authoritative TUV Rheinland low blue light certification, can effectively care for the user’s eyes.
And in the dimming mode, this time Honor 50 series took a different path – in the high light environment, the Honor 50 series using a lot of people who have long been familiar with DC dimming, and in the indoor, night, and another low light environment, Honor 50 is using high-frequency PWM dimming.
For DC dimming, in the past few years, because many people are affected by PWM dimming flicker problem, so DC dimming is almost treated as a panacea, OLED screen seems to use DC dimming can be once and for all, but in fact, it is not, PWM is resented the actual reason is low-frequency PWM, high-frequency PWM is a better solution, so Honor 50 series this time using 1920Hz high-frequency dimming.
What is the PWM function mentioned by Ming at the launch Today Honor talk about the Honor 50 series using 1920Hz high-frequency PWM dimming?
What is dimming, why do you want to dimming?
Because we have to look at the contents of the phone normally in a different light, you need the screen according to the strength of external light changes, make the corresponding brightness change, the process of changing the brightness is dimming.
Honor 50 series is equipped with both high-frequency PWM dimming and DC dimming two dimming methods, in bright environments, such as sunny weather outdoors, DC dimming can play more advantages, so this time the Honor 50 series is DC dimming.
However, in reality, most of the time we are using the phone indoors in such dark conditions, and the human eye is more sensitive to low light, but low light DC dimming is prone to color cast, Honor 50 series will use high-frequency PWM dimming, through the combination of high-frequency PWM dimming (low light) and DC dimming (high light) to bring the user a more extreme visual experience.
PWM dimming, more suitable for OLED low bright dimming program
DC is Direct Current, and DC dimming is to adjust the intensity of brightness by controlling the size of the screen backlight power. In the original production of cell phones, most of us are using the LCD screen, LCD screen is a bit like a “sandwich” – the top layer is the touch layer, the middle is the display layer, the bottom is the backlight layer so that each layer of uniformity are very high. At this time, we can directly control the brightness of the screen by adjusting the power of the screen backlight, which is DC dimming.
DC dimming is not fully applicable to OLED screens, this is because OLED screens are self-luminous, the brightness of the screen is generated by the current through each pixel unit, an OLED screen has millions of pixel units, in a high brightness environment, each pixel unit can be fixed at a higher display pixel current, bringing uniform and accurate imaging,
However, in a low brightness environment, when the current through the pixel unit is low, slight current fluctuations will cause differences. The brightness difference between the pixels, the appearance of the color cast, is the ragged screen that everyone sometimes mentions, the lower the brightness, the more obvious this phenomenon.
PWM is the abbreviation of “Pulse Width Modulation”, that is, pulse width modulation. PWM dimming is to keep all OLED pixel units at a high display power, through the high-frequency “bright screen-off – screen-bright – screen-off screen.”
Bright and dark alternately, use the visual residue of the human eye to control the screen brightness-the longer the bright screen state lasts per unit time, the brighter the screen, and vice versa, the pixel unit has always maintained a consistent high-power display, PWM dimming can bring a uniform and accurate display.
However, although PWM dimming can bring better display effects, after all, the principle of PWM dimming is the flicker of the screen, too low-frequency flicker is also not a perfect solution, and the Honor 50 series 1920Hz high-frequency PWM dimming is the further upgrade of the low-brightness down-dimming solution.
1920Hz, so that the eye “invisible” strobe high-frequency dimming
PWM “bright screen – off screen – bright screen – off-screen” principle of operation also means that if the dimming frequency is too low, the screen will appear to flicker, stimulating the eyes. Generally speaking, more than 70Hz strobe human eyes will not feel the flicker, only feel the light and dark, so the current industry’s common practice is to use 240Hz PWM dimming.
But the human eye may not notice, the visual cells can still. Long time to receive low-frequency strobe stimulation, the human eye will produce muscle fatigue, causing eye and even body discomfort response. If you use one phone to photograph the screen of another phone, you can see the screen flickering streaks, very harsh.
Reference IEEE LED lighting standards, the strobe range to reach 1250Hz to achieve a low risk to human health, the industry’s current common 240Hz there is a big gap, which is why many users complain about OLED screen “flash blind.”
To further solve the PWM dimming flicker problem, Honor’s R & D team in the screen and the underlying design of the circuit scheme has done a lot of optimization, bringing the industry’s most high-frequency 1920Hz high-frequency PWM dimming, in the user “invisible” place, to bring the user’s eyes and visual cells are really “Invisible” creative dimming program, while solving the two major problems of chromatic aberration and blinding.
Maintain the ultimate experience where users can’t see. Is it worthwhile to invest in R&D in places that are difficult for users to notice? In Honor’s opinion, it is the essence of innovation is to bring users a more ultimate product experience, not to find marketing gimmicks, even though users may not notice it, but as long as it brings users a better product experience, it is worth our investment.
Now consumers are using cell phones for longer and longer, it is important to protect their eyes, so PWM dimming looks like a small function, but it can bring consumers a better experience, and we will continue to upgrade this function to bring you a more ultimate screen viewing experience.