Products to try or avoid? PWM Flicker and Temporal Dithering Testing

GregAtkinson

photon78s I don't understand this statement:

Especially, brightness stability could become a critical problem because human sensitivity to brightness is increased under lower refresh rate

Maybe they mean "...human sensitivity to brightness instability or variation"??? I've put the whole paragraph here for reference.

However, in order to take advantages of LTPO, some technical challenges should be taken on. Modified pixel circuits and additional process steps are mandatory. Nevertheless, unknown problems may occur. Especially, brightness stability could become a critical problem because human sensitivity to brightness is increased under lower refresh rate [5], [6], [7], [8]. It has been reported that brightness variation is detected irrespective of charge loss in the storage capacitor even with LTPO [8]. The brightness instability under a low-refresh-rate may result from many unknown causes. Our measurement data show that electron trapping into the gate insulator of the driving TFT is one of the causes of the brightness instability. We propose a novel solution to this problem and report the effects of our solution under the low-refresh-rate driving condition.

When I read articles like this I'm reminded that I'm an amateur kind of grasping at straws hoping to find something...

photon78s

GregAtkinson

The frustrating thing is where are the "real pros" in the industry who have eyestrain issues? Anyways, my takeaway is that they are trying to lower power consumption (LTPO tech), and they are acknowledging the downside of "brightness instability" and trying to find a "solution" because the industry demands it. The rest is EE jargon.

simplex

photon78s

Sir, could you help me, and write, how to connect Fnirsi 1C15 to photodiode (which one?), to measure flickering…?

photon78s

simplex

I don't know about that specific model but for my testing I followed the discussion here: https://ledstrain.org/d/312-homemade-oscilloscope-to-detect-pwm-diy-guide

I think ideally use the thorlabs photodetector (PDA100A2) with your oscilloscope.

photon78s

Benq RD280U "4k+ Programming" desktop monitor. 28.2 inch.

https://www.benq.com/en-us/monitor/programming/rd280u/spec.html

Still just tolerating it and taking breaks. I leave it on light background coding setting. I do like to use the rear bias light set on lowest possible color temperature.

ninjaturtle

photon78s does it make you sleepy? Do you know its spectrum?

photon78s

Others have stated how coil whine on this forum and how it contributes to symptoms or just general frustration while using devices.

I was using a desktop with a 7950X and 4060 ti gpu with very loud high pitched noise coming from the gpu area. Tried tinkering with bios and power management settings made no difference. I then opened a program called airfoil maker from the X-Plane 12 flight simulator program and that seems to eliminate the noise! Interestingly in task manager, I don't see any significant rise in gpu or cpu use which is great for power consumption as well.

Nevermind, the noise comes back.

qb74

photon78s
People in these forums heavily underestimate the physiological & psychological aspects of eyestrain, especially when biology crosses into the electromagnetic world.

Coil-whine is a hardware "defect", one can attempt something like this to (maybe?) alleviate it.
https://old.reddit.com/r/watercooling/comments/1bzf4d8/how_to_reduce_gpu_whine/kypewax/

photon78s

ninjaturtle

In the brief time I was using it, it did not make me sleepy. YMMV. Unfortunately, I don't have the device I was using previously to measure spectrum but Benq does not advertise anytime special like quantum dots, etc.

ninjaturtle

Benq (especially the ones with eyecare/safe with the blue shifter of some nanometers) makes me sleepy and dumb during the day. Very bad. While some with blue peak around 445nm bother me very much, that is why I am interested in the spectrum. I am wondering if i can find any panel in the middle, maybe something like Apple monitors.

photon78s

I have look into that specific blue peak of 445 nanometers.

https://www.laserworld.com/en/laser-technical-faq/1153-what-blue-color-is-best-visible-405nm-445nm-or-473nm.html

For the Benq RD280U, the panel is listed as BOE MV282CVB-N10 from http://www.displayspecifications.com/en/model/90b93a88

JTL

qb74 Coil whine can be a crapshoot. From what I've experienced it can be a sum of per component unit variance, quality of AC input power, quality of output of PSU (maybe add to part of per component unit variance), function of total power consumption of components, etc. If you exchange components, you can get lucky and encounter no/little noise. Some people have had resolution by feeding their equipment from double conversion UPS's which provide a stable source of AC output power as well.

photon78s

qb74

Thank you for that link. Placing the computer as far away as possible and having obstructions between you and the source of the sound since it seems to be very high frequency directional sound might help as well and common sense.

qb74 People in these forums heavily underestimate the physiological & psychological aspects of eyestrain, especially when biology crosses into the electromagnetic world.

photon78s

Some e-ink screens claiming 60 Hz refresh rate. We shall see.

https://www.modos.tech/blog/modos-paper-monitor

https://www.tomshardware.com/monitors/portable-monitors/e-ink-screen-performance-hits-60-hz-with-10-3-inch-portable-touchscreen-monitor-from-dasung

https://www.techspot.com/news/106433-dasung-new-paperlike-103-portable-e-ink-monitor.html

From the modos website (emphasis mine):

The display is always refreshed to 1-bit mode first, then drives to 2-bit / 4-level greyscale after a preset time (for example, around 200ms). The process is non-flashing. This allows smooth typing while maintaining greyscale antialiasing for texts on the screen.

We are also planning to implement a 16-level greyscale mode with similar logic, but the 16-level will be flashing. Flashing/ flickering causes distraction and won’t work well for typing, but it could be useful for reading.

For the error-diffusion issue, we are evaluating using simpler dithering methods such as patterned dithering that would generate an image with arguably worse quality but could be more pleasant / causes less distraction when in typical desktop use.

qb74

@photon78s
Have you done any further testing of Windows 11? Curious on if there's a specific setting that caused larger brightness oscillations for you. Settings such as HAGS might impact it.
Have you used the same drivers when comparing 1809 and W11? Some drivers behave differently
https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/258634/tile-based-rasterizer-causing-artifacts/1914891/

photon78s

see https://ledstrain.org/d/938-check-your-neck-muscles

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