What is PWM, Why is it Important, and Why Did We Add This Test to Our Reviews?
Published: July 2015
Updated: November 2024
Perhaps you’ve noticed that the LaptopMedia team has started testing every laptop for Pulse-Width Modulation. PWM is used to regulate the brightness of LCD and LED displays. How does that concern us?
The pulsations can be bad for your health and more specifically for the users’ eyesight. They can lead to migraines, headaches, or other forms of discomfort after long-term usage. In many cases, those pulsations have a frequency somewhere around 240Hz. They cause multiple contractions and expansions of the pupils, which bears down negatively on your health. They are especially harmful in models with LED backlight because the colors of the emitted light are not as inert as the colors of the CCFL backlight and so they reach high amplitudes and rapid luminance changes.
Basically, the problem comes from the flickering of the light rather than from the crystals in LCD monitors.
➡️ Top Laptop PWM Ranking (Rated by negative impact on eyesight) ⬅️
Pulse Width Modulation (PWM) is an easy way to control monitor brightness. When you lower the brightness, the light intensity of the backlight is not lowered, but instead turned off and on by the electronics with a frequency indistinguishable by the human eye. In these light impulses, the light/no-light time ratio varies, while brightness remains unchanged, which is harmful to your eyes.
If there is PWM, it is better to have a high frequency of around 20,000 times per second instead of, say, 200. This is noticeable at different brightness reduction levels for different monitors. It is noticeable to a higher degree in LED than in CCFL backlights due to the former’s lower afterglow and higher nominal diode brightness.
Below are the waveforms of 4 displays.
1️⃣ The first one doesn’t emit pulse-width modulation, which provides the option to work for extended periods of time.
2️⃣ The second is a classic PWM. Its aggressive pulsations at a low frequency put extra pressure on the eyes and brain.
3️⃣ The third also emits PWM, but it has an extremely high frequency, which is considered to be less harmful.
4️⃣ The fourth one doesn’t flicker unless the brightness is <25%, so it is eye-friendly in practically every normal usage mode.
✅ OUR SOLUTION
To minimize the harmful effects of devices we’ve brought into our homes and can’t part with. While we might not stop using them, our lab has enabled us to deeply investigate and develop a suitable solution for our users.
From now on, every notebook entering LaptopMedia’s lab will receive a custom package of three profiles: “Design and Office”, “Gaming and Movies,” and “Health-Guard.” These profiles will be sold digitally at a nominal price. By purchasing these profiles, users obtain a valuable product and support the growth and expansion of our lab, where we conduct specialized research.
Each profile is tailored for each display model.
For PWM-controlled backlights, the profile lets you dim the brightness, ‘closing’ the pixels through a special PWM-Free slider, avoiding PWM. You can also use this slider to dim your screen further in case the brightness of your display is too high, even when you’ve lowered the Windows slider to the minimum.
But the “Health-Guard” profile offers more than just reduced brightness. The Health-Guard profile reduces the white temperature to around 5750-6000 K, while maintaining perceptually accurate colors, and adequate contrast.
Color accuracy is a priority – whites stay white, blues stay blue, etc., avoiding eye-straining reddish tints.
All these features distinguish the “Health-Guard” profile from free “color warming” alternatives.
Here is a comparison of two spectral diagrams from a modern notebook display emitting ‘white’ light. The first one is without a profile, while the second represents the “Health-Guard” profile.
How to Buy?
For every laptop that visits our lab, we create display profiles, which can be found in our detailed reviews. We also have a LaptopMedia Profiles Supported Laptops List page, where you can find all the machines for which we have created profiles over the years.
You could also place an order here but don’t forget to tell us an e-mail with your exact panel model. Scroll down to see where to find it.
Εκτός από τη λήψη αποδοτικών και φιλικών προς την υγεία προφίλ, αγοράζοντας τα προϊόντα της LaptopMedia υποστηρίζετε επίσης την ανάπτυξη των εργαστηρίων μας, όπου δοκιμάζουμε συσκευές για να παράγουμε τις πιο αντικειμενικές δυνατές αξιολογήσεις.
Design and Office
Το προφίλ Design and Office κάνει τα χρώματα της οθόνης όσο το δυνατόν πιο κοντά στην πραγματικότητα.Ιδανικό όχι μόνο για επαγγελματίες αλλά και για καθημερινούς χρήστες, πληροί τα πρότυπα sRGB (λευκό σημείο D65, γάμμα sRGB) με ελάχιστο DeltaE για ακριβή αναπαραγωγή χρωμάτων στο πάνελ σας.
Gaming and Movies
Έχετε παρακολουθήσει ποτέ μια ταινία όπου, κατά τη διάρκεια σκοτεινών σκηνών, μετά βίας βλέπετε τίποτα; Πολλές οθόνες αποτυγχάνουν να διακρίνουν σωστά τους σκούρους τόνους. Το προφίλ μας Gaming and Movies ενισχύει την απόδοση σε χαμηλό φωτισμό, όπως η τεχνολογία HDR, χρησιμοποιώντας μια καμπύλη γάμμα προσαρμοσμένη στην ανθρώπινη αντίληψη — ιδανικό για παίκτες που αναζητούν ταχύτερες αντιδράσεις και πιο καθαρά γραφικά.
Health-Guard
Το προφίλ μας Health-Guard προστατεύει τα μάτια σας εξαλείφοντας το τρεμόπαιγμα (PWM), μειώνοντας την καταπόνηση και την κόπωση, και ελαχιστοποιώντας την επιβλαβή έκθεση στο Μπλε Φως που μπορεί να διαταράξει τον ύπνο και την υγεία. Χρησιμοποιεί λογισμικό dimming και μια καμπύλη γάμμα προσαρμοσμένη στην ανθρώπινη αντίληψη για άνεση και ασφάλεια κατά τη χρήση της οθόνης.
Αποκτήστε Όλα Τα Προφίλ Με 33% Έκπτωση!
Where to find my exact panel model?
One of the best ways to do that is with an app like HWINFO – it’s free, and its portable version doesn’t need installation:
Installation and Usage
For easy use and switching between profiles, we developed the LM Profiles 3.0 app. Just download it, then drag and drop the profiles onto the application. That’s it!
You can now effortlessly switch between modes and take advantage of the PWM-free brightness slider when the “Health-Guard” profile is activated (to ensure that PWM is eliminated, make sure the Windows brightness slider is set to maximum).
Have Questions?
Feel free to reach out to us through our Contact Us page.
Author: Simeon NikolovEditor-in-Chief at LaptopMedia.com with 20+ years of experience in testing and analyzing laptops and mobile devices.
Author: eng. Kroum NikolovHead of Engineering at LaptopMedia.com, inventor and innovator with 40+ years of experience in electronics and high technology.
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