What is Flicker-Free Technology and PWM? (Jargon Free)

by Lisa Hayden
What is Flicker-Free Technology and PWM

Are You Wondering What is Flicker-Free Technology and PWM?

In your search for the best monitor in the market today, you might come across specifications like flicker-free technology and PWM. You ought to know that these features affect your usage, and this is why understanding these terms is essential; what this technology is and how it affects your experience as a user.

To begin with, flicker-free technology, also known as Flicker-less and Anti-flicker, refers to a monitor that does not utilise PWM or Pulse-Width Modulation to reduce a monitor’s brightness setting.

The PWM method, on the other hand, refers to the rapid turning on and off of the backlight, with its flickering frequency naked to the human eye. PWM is known to cause eye strain and headache attacks.

The good news is that the latest monitors are flicker-free, meaning they use direct current modulation to control the brightness settings, which in turn delivers a constant stream of light across all brightness levels.

In this day and age, the majority of monitors are being advertised as flicker-free, but in reality, most are not. Display monitors that use PWM introduce flicker at lower brightness levels (lower than 20% to 30% sometimes below 50%). This is a major concern for individuals who prefer lower brightness levels, whether they are in a dimly-lit environment or when the monitor luminance is strong, even below 50%.

Consequently, there are completely flicker-free monitors that don’t include this information in their product’s specifications. Most monitor evaluations include whether the products utilise PWM to control brightness levels.

Flicker-Free Monitors

flicker free monitors

Flicker-free is a term for video displays that operate at high refresh rates. Its main objective is to eliminate the perception of screen flickers. To keep things simple, flicker means that a display monitor takes time to reproduce the entire screen of the desktop. Given this, if the flicker of a display is high, it has a direct impact on your vision. In essence, monitors with higher flicker rates are better than those with lower values.

What are the Benefits of Using Flicker-free Displays?

Flicker-free monitors successfully alleviate eye strain, which makes them an ideal display for those who use their PC for extended periods.

There are individuals who are more sensitive to flicker. They are the ones who suffer from headaches when they stare too long at the screen. Traditional LCD monitors make use of CCFL tubes as backlights, which normally flicker as this is how they work. In addition, these monitors emit glaring blue light, which can exacerbate their headaches and eye strain.

Display monitors fitted with LED backlights were meant to remedy this problem, but LEDs typically go on or off to make the screen either darker or brighter. The LEDs are pulsed at a fast rate or slow rate, which can be perceived by most people as flicker resulting in eye strain and headaches, too. A conventional LCD monitor operates at 60Hz refresh rate.

On the other hand, Flicker-free LCDs operate at 120Hz refresh rates or higher. As a result of the speed increase, it’s difficult for the eyes to perceive flicker easily, so they also lead to headache attacks and eye fatigue. There are also those who won’t suffer from eyestrain at this speed, too. There are also LCD screens that operate at 240Hz.

In essence, the faster or higher the frequency in Hertz, the more comfortable and easier the display will be on the eyes, and the less ghosting will develop when pictures or clips move across the screen.

Pulse-Width Modulation

pwm monitor technology

PWM or pulse-width modulation is typically detected on laptop displays at high brightness settings, those at 99% brightness or below. This is definitely not good news for users as using these monitors can result in eye stating and headaches, too.

Simply put, PWM is a very rapid on and off states of digital signals to achieve a plain analogue signal. If you set a monitor at 70% brightness, you simply need to maintain the digital signal on for 70% of the time and off for 30% of the time your display is in operation.

The on and off states are being achieved rapidly at frequencies measured in Hertz (Hz) or the number of times per second. In essence, the faster the frequency, the less noticeable the off states become, mimicking what an analogue signal would typically produce.

Should I Be Concerned about PWM?

flicker free pwm worth it?

To keep things simple, yes. PWM is utilised not only for LCD monitor brightness but also in most forms of finite control across modern electronic devices. Fan speed control is implemented through PWM. Newer technologies found in smartphones also implement PWM, but at a smaller scale.

Why does PWN Cause Nausea, Headache, and Eye Strain?

Low PWM frequencies on a display monitor are unpleasant by our own standards. Low PWM results in eye strain, headache, and nausea due to the constant blinking of the screen backlight at low frequencies. These low noticeable frequencies may cause the rapid contractions and expansions of the pupils.

On the other hand, high frequencies are less straining to the eyes as a result of the flicker fusion threshold of the human eye. This feature allows flickering light at high frequencies to appear as if it was on the entire time. When the frequency is low, unwanted symptoms then appear and cause problems to the user.

To eliminate these problems, your monitor’s brightness levels should be adjusted to safe viewing between 30% and 40% or depending on your monitor’s specifications. It should not be forgotten that as brightness levels go down, the need for higher PWN increases, due to the lengthier off states. This means the interval between the in states must be kept short to keep a steady appearance of the flickering light.

PWM is utilised in many modern electronic devices, so there simply is no way to escape this type of technology. It is not a bad technology at all, and the same goes of Flicker-free technology, but poor implementation on displays can result in serious symptoms among its end users.

The hope is that innovations can result in resolving these issues for displays that utilise PWM and Flicker-free technology. We can only hope that in the near future, manufacturers can step up their game to produce laptops with displays that feature the same ideal specs of those found in desktop monitors. For now, end-users like you and me should make the necessary changes in the brightness settings, so you can avoid eye fatigue, nausea, and headache, all of which reduce productivity. 

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