Impact of PWM Dimming Over 1440Hz
The recent release of the Honor 90 Series smartphones has sparked a debate regarding the impact of high-frequency pulse width modulation (PWM) dimming on eye protection. While Honor claims that their ultra-high-frequency PWM dimming at 3840Hz enhances eye protection, Huawei’s perspective, as voiced by their CTO Bruce Lee, suggests that the benefits of PWM dimming frequencies exceeding 1440Hz are negligible.
Understanding PWM Dimming:
PWM dimming is a commonly employed technique to adjust the brightness of displays, including those found in smartphones. It involves rapidly switching the display’s backlight or pixels on and off at a certain frequency, creating the illusion of reduced brightness. Higher PWM dimming frequencies, such as 1440Hz, 1920Hz, and even 3840Hz, have been touted as advancements in reducing flickering and minimizing eye strain.
Honor’s Stance:
Honor, with their latest Honor 90 Series smartphones, has embraced ultra-high-frequency PWM dimming, emphasizing its potential benefits for eye protection. According to Honor CEO Zhao Ming, the impact of PWM dimming on eye health encompasses various factors beyond just frequency, such as fluctuation depth and duty cycle. They argue that it is incorrect to make generalized statements solely based on frequency, suggesting that other aspects of the dimming process also play a role in eye comfort.
Huawei’s Counterargument:
Huawei’s CTO Bruce Lee recently shared a video in which a blogger explains that the benefits of PWM dimming frequencies exceeding 1440Hz are practically negligible for eye protection, especially in low brightness environments. The blogger contends that regardless of the advertised dimming frequency, the performance of PWM dimming at low brightness levels (below 10 to 15 nits) remains unrelated to the specified number. This challenges the notion that higher frequencies inherently lead to better eye protection.
Why is the benefit of PWM dimming with a frequency exceeding 1440Hz almost zero for eye protection, this video helps me explain clearly.
Said, Bruce Lee, Huawei’s CTO.
The Complexity of PWM Dimming:
The issue at hand is undoubtedly complex, with multiple factors contributing to the overall impact of PWM dimming on eye health. While PWM dimming at higher frequencies may reduce flickering perceptible to the human eye, the interaction between frequency, fluctuation depth, duty cycle, and ambient lighting conditions is not yet fully understood. Studies on the topic have yielded conflicting results, making it difficult to draw definitive conclusions.
