311
The world's first colour e-ink monitor is essentially a 25-inch Kindle
(www.creativebloq.com)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 04 Aug 2023
311 points (97.0% liked)
Technology
34987 readers
443 users here now
This is the official technology community of Lemmy.ml for all news related to creation and use of technology, and to facilitate civil, meaningful discussion around it.
Ask in DM before posting product reviews or ads. All such posts otherwise are subject to removal.
Rules:
1: All Lemmy rules apply
2: Do not post low effort posts
3: NEVER post naziped*gore stuff
4: Always post article URLs or their archived version URLs as sources, NOT screenshots. Help the blind users.
5: personal rants of Big Tech CEOs like Elon Musk are unwelcome (does not include posts about their companies affecting wide range of people)
6: no advertisement posts unless verified as legitimate and non-exploitative/non-consumerist
7: crypto related posts, unless essential, are disallowed
founded 5 years ago
MODERATORS
It's not the blue emitting light that causes eyestrain on OLEDs, it's the low frequency pwm used to control brightness. Basically all the pixels turn on and off a few hundred times a second, not slow enough for your brain to consciously notice it, but fast enough for your eyes to react to what is in effect a strobelight right in front of your face. That is how dimming works on an OLED.
You end up with devices that still cause headaches and dizziness because they flicker in this manner, but are "eyesafe certified" because they filter out the blue light right before bed.
That got me thinking: couldn't that be solved by adding a layer in fron akin to a phosphor screen which "buffers" the light a bit thus bridging the switching which should reduce flickering?
Not without losing brightness. White LEDs work that way and are less bright than an uncovered LED of the same power. Some of the light from the LED becomes waste heat instead of light when the phosphor absorbs it.
Also, not without losing response time. Part of the point of using LEDs for displays is that they can change brightness very quickly.
I think this would result in some pretty intense ghosting and other undesirable artifacts.
Ghosting on CRTs wasn't too bad, mostly imperceptible even
That’s a good point, I don’t remember much ghosting on those. I guess it might depend on the phosphor used. If it was tuned to only fluoresce for that imperceptible off time and no longer it would probably work.
I guess it’s a similar idea to quantum dots, but if those quantum dots fluoresced for just a bit longer.
Eventually, there will something like a 1000 Hz monitor. At some point, it will refresh too fast for the brain to register any difference.
OLED TVs and desktop monitors don't use pwm, though they do have very slight brightness dips every refresh.
Afaik laptop and phone OLEDs do use (low frequency) pwm.
Fuck PWM, all my homies hate PWM
Why is the pulse width so large? LEDs can toggle millions of times per second, not merely hundreds.
It is possible, by the way, to dim an LED without PWM the old-fashioned way: by varying the voltage of the power supplied to it (“DC dimming”). You can see this in devices that have an indicator LED that stays on for a few moments before fading out. What's happening there is a capacitor in the device is (briefly) powering the LED. As its charge depletes, the voltage drops, and the LED dims. However, controlling LED brightness this way is a great deal less accurate than PWM, creating color distortion at low brightness. See related Android Police article.