2021 Apple iPad 10.2 (9th Gen) PWM: 40000 Hz. What does that mean?

[⛤ . shzk178 ˚⊹]

Hello. I would like to buy The Ipad 9th, and according to "notebookcheck" this Ipad has 40000 Hz ( Screen flickering / PWM detected )
What does that mean for casual user who would like to play some games or just to watch some movies? Thank You.

[Ančiukas ❤]

PWM is a way for various display panels to adjust their brightness. Instead of dimming the backlight, the device actually makes it flash very quickly which reduces the amount of light that comes out, which lowers the overall brightness our eyes perceive. Normally the flashing is so fast, the human eyes can't actually see it but some display panels might flash at a lower rate, which some people can see.

PWM 40,000Hz means the display flashes 40,000 times a second. For most users, it shouldn't really matter. This is only relevant to people sensitive to display flicker.

[DevaVictrix]

That’s fast!!!

[ChickenBalls]

İlk olarak DevaVictrix tarafından gönderildi:

That’s fast!!!

lol its not refresh rate though...


https://www.notebookcheck.net/PWM-Ranking-Notebooks-Smartphones-and-Tablets-with-PWM.163979.0.html

PWM is short for pulse-width modulation and describes a flickering of the background illumination to reduce the luminance. Sensitive users may see this flickering below a certain frequency and get tired eyes or headaches.

Ideally you don't want any flickering at all so 0HZ is better than 40KHZ

[DevaVictrix]

İlk olarak ChickenBalls tarafından gönderildi:

İlk olarak DevaVictrix tarafından gönderildi:

That’s fast!!!

lol its not refresh rate though...

It's just a pretty impressive rate given things like light bulbs flash at 50Hz (in the UK, at least). It's something I've never come across or heard of before.

[ChickenBalls]

İlk olarak DevaVictrix tarafından gönderildi:

İlk olarak ChickenBalls tarafından gönderildi:

lol its not refresh rate though...

It's just a pretty impressive rate given things like light bulbs flash at 50Hz (in the UK, at least). It's something I've never come across or heard of before.

uh some of the decent laptops are at over 100K Hz
Apple and their products are not superior or unique.

the screen of this cheap 260Euro Nokia tablet got a PMW frequency of 3 846 000 Hz, thats 3.86MHz
https://www.notebookcheck.net/Nokia-T20-Tablet-review-Pad-with-LTE-lasts-forever.581060.0.html

[_I_]

wpm is the % of on/off time for the pulse
____ = 0%, _-_- = 50%, ---- = 100%

1khz is a normal freq, when its used for data, fan controllers or servo or other d/a devices
but voltage controllers use a much higher freq, 40khz is in the normal range for that

on a display, its the rate that the led backlight turns on/off to make it bringt/dim

[Masychefx2]

60hz crew checking in

[Cathulhu]

Too bad you can't read properly.

[Pepe]

If you care about your eyes, you'll buy an iPad Air. That one is flicker free, no PWM. PWM is just a cheap solution that many companies use to make more profit rather than putting a proper DC dimming display in their devices.

40000Hz is a big number, most people will never notice any flicker at that speed, it's definitely better than other tablets out there. But why risk it and why give companies money on flawed designed hardware, when there is a proper solution they could put in? These tablets are not cheap at all, why did Apple go cheap on the specs? iPad 7 had no PWM. iPad 8 had no PWM. I think no iPad had PWM until now (except for iPad Pros with OLED - and iPhones with OLED - OLEDs still suck because it's harder to create some kind of DC dimming, but some LG TVs have flicker free displays, so there is a solution, but nobody wants to put the money in).

Apple is making a profit in the detriment of your health.

Just because we can't detect the flicker, it doesn't mean it's not there. The brain can't process so many FPS, but the eyes' cells do have a way faster response time. Long time exposure to intense stimuli can lead to eye strain on some people.

If you don't intend to use the tablet much (30-60 mins a day), I guess it's fine. More than that, no way!

Since I did experience some eye strain and head aches on some older devices and I found out about the source of the issue, I am trying to protect my eyes as much as I can, that means always buying flicker free monitors or devices with flicker free displays. I've seen how poor displays broke the vision of close family, friends and coworkers. They all started wearing glasses, and even if vision deterioration can't be entirely blamed on the displays, I think a large amount of it can. They didn't have any bad side effects like me looking at a bad monitor, so they've continued to stare at it for hours, without questioning the poor built quality. No problems detected, no change from the company. "Win win". And win for the opticians. I saw people looking at a blurry text, and they thought it's fine, they thought it's their eyes or their glasses. The greatest combo I've seen was blurry text + wrong colors (blueish or pinkish) + visible flicker. Some people have poor vision and they don't even realize it how much a monitor can add up to their lens size in a few years.

Anyway, take care of your eyes if you can.

[Ančiukas ❤]

If possible, you can visit a store with an iPad 9th generation on demo and try it for yourself to see if your eyes can detect the flicker.

[_I_]

if its for running an oled, then its the pulse rate for the leds blinking on/off, not refresh rate

wave/shake a finger in front of it, if its not smooth, thats how fast the leds are blinking