Let me cross post why image retention occurs.
Right now, it looks like the inversion algorithm on this LCD may have a bug.
A firmware upgrade probably could fix this problem, but I don't think everybody realizes that it's an scaler/TCON bug on the inversion algorithm.
Why Image Retention / Burn-In Sometimes Occur On LCDs
However, if a stationary (non flickering) image causes image retention on this panel, then there is a definite bug with the inversion algorithm and it cannot be fixed without a firmware upgrade.Chief Blur Buster wrote:Crossposting here.Image Retention ("Temporary Burn-In")Joel D wrote: ↑19 Sep 2020, 13:26Dang. Thats the weirdest thing ever. I've had the same static image on the screen for hours at a time, never had a issue. Wow, I'm amazed this happened in such a short time. Furthermore, omg that retention in general is loud and bold ! Most bold IR I've ever seen. How high do you have your brightness ? IMO 99% of people use their monitors way too bright, in which could be culprit to image retention quicker. It is also why they see outrageous screen bloom and backlight bleed.
From Temporary Static Electricity Buildup In Pixels
Flicker patterns such as:
- Emulator black-frame insertion
- 3D-glasses software
- Certain motion tests (including but not just TestUFO's Sync Track)
- Anything that does exactly a half-Hz or quarter-Hz flicker with no dropped frames for a sustained period
Can create temporary LCD image retention. It's a static-electricity behavior when a flicker goes in sync with the positive-negative voltage inversion algorithm, and creates this inversion-related image retention.
This is temporary and you just display video full-screen, or some other thing that really exercise the whole screen -- e.g.
This gets rid of the per-pixel static electricity buildups.
You also get the same problem in anything that flickers pixels in-phase with the positive-negative voltages of the LCD inversion algorithm.
https://www.google.com/search?q=techmind+LCD+inversion
Voltages inverts to try to balance the electricity buildup in the panel, but flicker patterns that go in sync with this, can cause a voltage unbalance = static electricity build up, as an LCD pixels can accidentally behave as capacitors.
The layered nature of an LCD unfortunately creates unavoidable capacitance effects that interfere with operation.
Modern LCDs try to avoid this by using spatial and temporal alternating voltage (positive voltage, then negative voltage, then positive voltage, then negative voltage, and so on)
It's often in a chessboard pattern spatially, which sometimes produces an inversion artifact. Normally this is invisible when the positive voltages are perfectly balanced with negative voltages. But the voltage balancing is not always perfect, so you see this:
However, this is also done temporally -- the voltages swap (like an inverted chessboard) at the next refresh cycle.
Now, if you flicker perfectly (at half Hz), then pixels that gets the "higher voltage" (different brightnesses = different voltages) are always getting negative voltages or always getting positive voltages = static electricity buildup = image retention.
Not all screens use the same inversion pattern / inversion algorithm, so some LCDs don't get image retention easily, while others do. In an ideal world, we would be now using error-diffusion temporal dithering or some randomized dithered inversion algorithm, to be fully immune to all material. But in the real world, the panel makers don't do that, and just settle for simple patterned inversion algorithms which are easier to do at high refresh rates (complex invisible inversion processing can be costly). Historically, this is why inversion patterns often have showed up more commonly on high-Hz monitors -- for example, the early ASUS VG278HE (one of the first-ever 27 inch 144Hz monitors) was particularly known for its chessboard artifact during 3D glasses operation.
- The chessboard artifact is the quirk from spatial component of the inversion algorithm.
- The image retention is the quirk from temporal component of the inversion algorithm.
Thusly, I am not surprised that the world's first panels of a specific refresh rate has some "inversion-related quirks". Every single 240Hz 1ms IPS panel currently has this pixel-as-capacitors quirk at the moment, that only shows up with sustained exact-Hz flicker patterns. As time passes, I'm sure this will improve, wit h improved inversion algorithms.
Since the pixels have inadvertently behaved like capacitors because of the layered nature of an LCD worked against proper pixel operation. Now you got to drain the charge -- the built-up static electricity stored in the pixel.
Draining the pixel static electricity charge is best done by playing highly active video material. If you want to erase image retention faster, use full screen random-color flashing (fully randomized colors).
HOW TO FIX FIX: Play highly active fullscreen video or animation.
Play pixel fixer software https://www.youtube.com/watch?v=39HUG7QrQi8 (play at 2X speed, it's too slow)
Or simulated analog TV noise https://www.shadertoy.com/view/tdXXRM -- this usually erases image retention faster.
I prefer simulated analog TV noise as a quick burn-in eraser.
Make sure to click the full screen button
While a technology quirk, it is not an RMA defect at all.
Also, if you want to keep using emulator BFI, use the new 180Hz BFI feature now found in some emulators, a 3-cycle flicker pattern never produces image retention on majority of monitors -- RetroArch is building this feature in now.
NOTE: Some old LCDs had inversion-algorithms bugs tj(firmware bugs or hardware bugs) that caused burn-in even with stationary images, especially at certain picture settings. Also, certain manoevers such as overclocking an LCD may cause inversion algorithms to fail, creating a more image-retention-sensitive LCD. You will immediately know if image retention occurs with stationary images instaed of moving images.
They need to release a firmware upgrade ASAP.
In theory an RMA can be avoided if:
(A) Quarantine until firmware fix
(B) Install new firmware
(C) A long retention-undo by playing some active imagery (full screen action video) for hours, at a time proportionate (~10x as long as you displayed something that caused image retention).
Then the panel should be pretty clean, without needing to pay for shipping.
But this is contingent on Acer releasing a firmware fix that can be installed by users. This is one of the mandatory requirements of the Blur Busters Approved program, a commitment to release bugfix firmware upgrades.