Backlit AMOLED panel??

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AgentBuBu

Senior Member
Jun 3, 2016
333
85
It's my first contact with an oled panel from close view and personal usage. I noticed that the display acts like and LCD which is backlit even if there is a black image. Is the same supposed to happen to AMOLED? I thought the pixels would light themselves and if there is a black image, the screen should look the same like when its turned off - and it doesnt act like that, there is a dim light that's showing up when the screen is on and displaying a black image. Is it normal? Is the screen replaced with an LCD? ( i bought the phone used )

THanks!!
 

blackhawk

Senior Member
  • Jun 23, 2020
    2,734
    550
    Easy test for an LCD, view through polarized glasses and rotate.
    LCDs have a polarization filter so a second polarized lense with block the polarized light at some point in it's rotation axis.
     

    AgentBuBu

    Senior Member
    Jun 3, 2016
    333
    85
    I tried to take some samples of the pixels with another phone, here are the results:
    MI MIX 3:
    IMG_16-04-2021_22-07-04_8.1.011.NIGHT.jpg
    IMG_16-04-2021_22-24-45_8.1.011.NIGHT.jpg
    IMG_16-04-2021_22-25-11_8.1.011.NIGHT.jpg

    ------------------------------------------------------------------------------
    Photos taken of a LCD tablet:
    IMG_16-04-2021_22-59-45_8.1.011.NIGHT.jpg
    IMG_16-04-2021_23-00-01_8.1.011.NIGHT.jpg
    IMG_16-04-2021_23-00-48_8.1.011.NIGHT.jpg

    -------------------------------------------------------------------

    Is it possible to say from these pictures that the display on the mi mix isnt RGB Stripe?
     

    AgentBuBu

    Senior Member
    Jun 3, 2016
    333
    85
    Like, maybe im considering it wrong, but i thought viewing from this angle an AMOLED panel with a black image should be the same like the second image when its off:
    1.jpg
     

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    AgentBuBu

    Senior Member
    Jun 3, 2016
    333
    85
    Searched through some logs and apps and found out its a samsung ea8076 - same display which is on the K20 Pro/mi 9t pro. Everywhere i searched i've found only amoled, i also looked up on the internet and there are available TFT replacements for the mix 3, i think it's amoled but it's very unusual - if i put a true amoled black image on the screen and increase the brightness, the screen gets brighter, even if there's nothing else than black pixels. Also, the maximum brightness is slightly lower than the one of my older phone ( RN3 Pro). I don't know what to believe at this moment.
     

    CriGiu

    Senior Member
    Apr 6, 2012
    832
    571
    to add on this, an easier test may be to check if a black background/image results in no light coming from screen (easier to see in the dark). LCD displays emit light (the backlight is still on) even for black images, oled do not
     

    blackhawk

    Senior Member
  • Jun 23, 2020
    2,734
    550
    to add on this, an easier test may be to check if a black background/image results in no light coming from screen (easier to see in the dark). LCD displays emit light (the backlight is still on) even for black images, oled do not
    The easiest foolproof way is view with polarized sunglasses and rotate.
    LCDs show their stripes...
     
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