Why does my laptop screen get dark?

Question

laptops

For a long time I began to notice that when switching from a browser tab, which is decorated in dark to light colors, the brightness automatically increases, the eye can see how the brightness becomes "greater". How to fix it? I want to have static brightness.
Notebook Xiaomi Mi Notebook pro 15.6

upd: Do not write about power saving and brightness settings.

Answer 1

These are modern laptops with dynamic color range and contrast, making the picture more beautiful depending on the content. And obviously at some low level, it is unlikely to turn off.

Answer 2

In the screen settings there should be a parameter "brightness"

Answer 3

Disabling floating brightness via the power supply circuit.
We start the command line.
Type powercfg /L and press Enter.
I have two power plans - we get the following data:
Existing power plans (* - active)
------------------------------- ----
Power Scheme GUID: 2e3f1b4e-1ea8-4c80-b601-f4e78480e9ab (High Performance) *
Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced)
Open notepad and type the following lines:
powercfg -setdcvalueindex "GUID power schemes" 7516b95f-f776-4464-8c53-06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0 - shutdown when running on battery
powercfg -setacvalueindex "Power Scheme GUID" 7516b95f-f776-4464-8c53-06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0 - Power off
power scheme GUID with yours.
Do for each power scheme.
If you want to return everything back, then we replace the zero at the end of the line with one.
The result should turn about a:
powercfg -setdcvalueindex 2e3f1b4e-1ea8-4c80-b601-f4e78480e9ab 7516b95f-f776-4464-8c53-06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0
powercfg -setacvalueindex 2e3f1b4e-1ea8-4c80-b601- f4e78480e9ab 7516b95f -f776-4464-8c53-06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0
powercfg -setdcvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 7516b95f -f776-4464-8c53-06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0
powercfg -setacvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 7516b95f -f776-4464-8c53 -06167f40cc99 FBD9AA66-9553-4097-BA44-ED6E9D65EAB8 0 Enter
these commands on the command line.
You can save it in a batch file and apply it after the next update of the drivers for the video card.
The solution with floating brightness, if the previous method of treating the problem with "floating" brightness did not help
1. Press the Win + r combination
2. Enter "regedit" in the field and press Enter
3. Go to this path - HKEY_LOCAL_MACHINE\Software\Intel\Display\ igfxcui\profiles\media\Brighten Movie and change the value of ProcAmpBrightness to 0.00
4. Go to this path HKEY_LOCAL_MACHINE\Software\Intel\Display\igfxcui\profiles\media\Darken Movie and change the ProcAmpBrightness value to 0.00
5. Reboot the laptop