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

As some of you are considering trying older lenovo windows/linux laptops, I going to start a list here of potential replacement display panels for ThinkPad T480 and/or T480s that may work for some eyestrain wise.

1. https://www.panelook.com/LM140LF1F02_Panda_14.0_LCM_overview_48911.html (144hz refresh rate for a thinkpad!)
2. https://www.panelook.com/N140HCG-GQ2_Innolux_14.0_LCM_overview_41388.html (This is a low power IGZO FHD display for better battery life, IGZO means indium gallium zinc oxide as semiconductor material)
3. https://www.panelook.com/R140NWF5_R6_IVO_14.0_LCM_overview_36125.html (matte FHD touch screen, 6 bit color so not recommended for dithering reduction)
4. https://www.panelook.com/B140QAN02.0_AUO_14.0_LCM_overview_37246.html (hdr wqhd glossy)
5. https://www.panelook.com/B140QAN02.3_AUO_14.0_LCM_overview_33893.html (Non-hdr wqhd matte, what I am using in T480s)
6. https://www.panelook.com/LP140QH2-SPB1_LG%20Display_14.0_LCM_overview_40282.html (I prefer number 5 to this which came with my T480s)
7. https://www.panelook.com/N140HCA-EAB_Innolux_14.0_LCM_parameter_30063.html (has PWM)

How to guide:

https://forum.thinkpads.com/viewtopic.php?t=127439

https://www.ristrettorambles.com/upgrading-settling-into-the-thinkpad-t480/

https://www.ifixit.com/Device/Lenovo_ThinkPad_T480

https://www.ifixit.com/Device/Lenovo_ThinkPad_T480s

One thing to note is whether your machine comes with 40 pin or 30 pin cable and the eDP version and number of lanes. You may also have to use a pinout converter with one compatible with your chosen panel. When I replaced the panel on the T480s, the cable length was a just barely enough to reach the location of the slot on the panel. Another aspect to check is if you are using narrow or regular pitch pins. If you get a T480 the comes with a FHD touch display, it will greatly limit your options as to what panels can be swapped out without tinkering with eDP pinout adapters and motherboard to panel cables.

Resources for understanding pinouts and cables:

https://hackaday.io/project/179868-all-about-laptop-display-reuse/log/209701-common-edp-laptop-panel-pinouts

https://www.reddit.com/r/thinkpad/comments/uw0tit/t480s_from_fhd_touch_to_non/

https://old.reddit.com/r/thinkpad/comments/up3bql/seeking_advice_for_p14s_screen/

https://www.reddit.com/r/thinkpad/comments/i9oqr1/comment/g4fm42k/?rdt=45559 (see 30-pin normal eDP cable FRU 01YR501)

https://www.reddit.com/r/thinkpad/comments/v8tf2n/t480_screen_buying_advice_in_eu/?rdt=53836

Pin Pitch Converter Example

simplex

It doesn't look to me to be vertical green lines but white lines or spaces between horizontal rows. See this:

https://www.dropbox.com/scl/fi/apr1qfjvta6m17a9xvy30/IMG_20240620_093854.jpg?rlkey=12w5qeab6pc67pxmndzjb5bm0&st=kaa8xjgw&dl=0

Ignore the rainbow moire but notice the lines in the lighter parts in the trees. And this seems to be a static artifact. Panel degradation?

simplex

Nothing is different on video as it is static and not flickering. Yes, it is even easier to see with naked eye. This is third time I've seen this. First on a legion 5 amd laptop, the NEC EA271U-BK monitor, and now this LG gaming monitor.

simplex

The one I have listed in my original post for this discussion in the table: LG 27gp95r-b

I still need to find the specific panel model. It was not present or maybe as noticeable when brand new out of the box only a few months ago.

Edit update:

The horizontal lines are what's shown in these videos expect mine is less noticeable.

https://www.youtube.com/watch?v=2agVKO-Ihkk

https://www.youtube.com/watch?v=1FcM1cb34Uc

simplex
I have no idea. Need to find their datasheet.

PWM waveform at 0% and 100% brightness using thorlabs pda100a2 detector. 20dB gain setting on photodetector produces this waveform. Close to flat at 0dB gain setting.

Same photodetector 20dB gain settings but for legion 7i laptop and samsung s10+ (both at max panel brightness) Photodetector placed close up to panel with no interference from ambient artificial light.

Samsung s10+

Legion 7i 2023 laptop

simplex

I use legion 7i everyday with no issues (always set to 240hz refresh rate and linux mint). As I said before, I don't use the s10+ as main phone only for testing screens and the s10+ does give me strain after about half hour of use. Others seem to not tolerate the 7i.

xiaomi 12s ultra at max brightness and "dc dimming" enabled in developer settings (measured using thorlabs pda100a2)

simplex

Still trying to find out how to enter service mode or similar to find out.

finding panel for LG 27gp95r-b high refresh rate monitor.

1. https://www.panelook.com/LM270WR8-SSE1_LG_Display_27.0_LCM_overview_64259.html
2. https://www.panelook.com/LM270WR8-SSD1_LG_Display_27.0_LCM_overview_62942.html
3. https://www.panelook.com/LM270WR8-SSA1_LG_Display_27.0_LCM_overview_48193.html

If not one of the above , some similar panel closest in spec to the the third one (SSA1)

HWiNFO64 returns LG [Unknown Model: GSM5BBF]

Nord N30 max brightness PWM:

https://imgur.com/a/muZaxkN

It looks bad but I can handle this much better than the oled samsung s10+ at max screen brightness.

versus samsung s10+:

All measurements at 20dB gain on pda100a2 photodetector.

HKC MB140CS01-4 is a compatible FHD lcd panel for T480 and most likely T480s thinkpad laptops.

https://www.panelook.com/MB140CS01-4_HKC_14.0_LCM_overview_60997.html

100% brightness still shows some flicker despite stating dc dimming in panelook. Tested using a T480, linux mint 21.3, full white rgb(255, 255, 255) patch. Not subjectively comfortable compared to 7i panel (see posts above).

(thorlabs pda100a2 detector at 20dB gain)

Zooming in with shorter 5ms timescale reveals 60hz flicker.