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

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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, which 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 utilize PWM or Pulse-Width Modulation to reduce a monitor’s brightness setting.

On the other hand, the PWM method 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, delivering a constant stream of light across all brightness levels.

Nowadays, most 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 significant concern for individuals who prefer lower brightness levels, whether in a dimly-lit environment or when the monitor luminance is intense, even below 50%.

Consequently, some completely flicker-free monitors don’t include this information in their product’s specifications. Most monitor evaluations include whether the products utilize 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 desktop screen. Given this, if the flicker of a display is high, it directly impacts your vision. In essence, monitors with higher flicker rates are better than those with lower values.

Related: Why Is My Monitor Flickering? Reasons And Solutions

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.

Some individuals are more sensitive to flicker. They are the ones who suffer from headaches when they stare too long at the screen. Traditional LCD monitors use CCFL tubes as backlights, which usually 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, leading to headache attacks and eye fatigue. Some 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 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 state of digital signals to achieve a plain analog signal. If you set a monitor at 70% brightness, you 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 analog signal would typically produce.

Should I Be Concerned about PWM?

flicker free pwm worth it?

To keep things simple, yes. PWM is utilized 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 smartphone technologies 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 rapid contractions and expansions of the pupils.

On the other hand, high frequencies are less straining to the eyes due to 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 appear and cause problems for the user.

To eliminate these problems, your monitor’s brightness levels should be adjusted to safe viewing between 30% and 40%, 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 utilized in many modern electronic devices, so there is no way to escape this technology. It is not a bad technology at all, and the same goes for Flicker-free technology, but poor implementation on displays can result in severe symptoms among its end users.

The hope is that innovations can resolve these issues for displays that utilize PWM and Flicker-free technology. We can only hope that shortly, manufacturers can step up their game to produce laptops with displays that feature the same ideal specs as 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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