How much PPI needed for OLED to look good?

Discussion in 'Mobile Devices and SoCs' started by orangpelupa, Jul 10, 2016.

  1. orangpelupa

    orangpelupa Elite Bug Hunter
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    Because I just saw an 5 inch phone with 720p OLED (Samsung Galaxy j5), and it looks much worse than LCD at the same size and resolution.

    Thin black text on white background looks annoying due to the weird color ringing.

    The pixels easily seen from normal viewing distance. It's not blocky. But looks like a fine fabric mesh.
     
  2. cheapchips

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    Slightly unhelpfully it'll depend! Just with Samsung, they have different production lines making panels with different subpixel properties, before you get into panels made by other manufacturers.

    I had a S5Neo, and the 1080p screen on that was really good. The phone was laggy and awful though, so I swapped it out after a week.

    Any Samasung 1440p panel should look awesome.
     
  3. Rurouni

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    It uses super amoled, thus pentile, thus the total number of subpixel is only 2/3 vs normal rgb screen. To have a comparable number of subpixel vs a rgb 720p screen, you need a 880p pentile screen.
    Edit: of course it wouldn't be as simple as that since it would mean that 880p screen will have more green subpixel vs 720p normal screen but less blue and red subpixel. For viewing pictures, 880p screen might look better than 720p normal screen, but for contrast thing like black text on white background, it might still look worse.
     
    #3 Rurouni, Jul 10, 2016
    Last edited: Jul 10, 2016
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  4. Grall

    Grall Invisible Member
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    Samsung uses "pentile" subpixel placement in some/many/all of its OLED phones, instead of standard RGB (or variation thereof) subpixel arrangement, you have RG-BG sets of subpixels (IE, more G than R or B). This supposedly improves display longevity (the blue subpixel in particular can be made larger), and perhaps more importantly, gives an artificially inflated pixel-per-inch figure, since there's 1/3rd fewer subpixels per pixel with this arrangement... :p

    Downside is weird moire patterns and other artifacting in certain imagery.
     
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  5. Lodix

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    I can still see spaces between pixels If I look close even with a 1080p on 5 inches, so for me I need 1440p for my phone.
     
  6. Silent_Buddha

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    It definitely depends on the panel.

    For the most part Samsung uses pentile while LG uses WRGB, which is closer to how LCDs handle sub pixels.

    Regards,
    SB
     
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  7. milk

    milk Like Verified
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    Does any pentile display phone handle sub-pixel anti-aliasing properling? Meaning: did anyone take the time to make a AA algo that js aware of pentile's unorthodox subpixel arrengement? Cause improper filtering of the image could be a great part of the cause for why their output looks so terrible.
     
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  8. Blazkowicz

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    I've sometimes argued for monochrome OLED on geeky sites, few or nobody ever seemed to be interested. I have other ideas like that : phone with rj45 ethernet, battery-powered PC-in-a-keyboard. Get in touch with me if you want ideas to be innovative (*).
    Apple did build their Macintosh empire by giving high res monochrome as the only option, leaving out low res color graphics and text modes.

    (*) My definition of an innovative product is of one that ships (else it's not a product), I've said nothing about it not being a market failure!
     
  9. Grall

    Grall Invisible Member
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    Heh, Blaz, we already have "retina"-level resolution color OLED screens... There's no present need to go monochrome just to reach high enough DPI; the window for that has closed already. :)
     
  10. milk

    milk Like Verified
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    It could be argued that for straight black on white fine text, "retina resilutions" is not above the threshold where a bit more dpi couldn't still affect legibility. That's why e-readers have higher dpis and are still increasing it with every major new release. For pretty much all other use cases and content though, retina-level is good enough.
     
  11. Grall

    Grall Invisible Member
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    There's 5.x-inch phones with 1440P screens out there, and they're so high rez that you couldn't even read the text if you used a regular 10, 12-point font and held it at normal phone distance. Text legibility is not an issue even on original Apple 3.5/4-inch retina screens.

    Also, if you really think phones need additional pixels, I believe there's also at least one phone with a 4k screen out there, which is just as ludicrous as it sounds... ;)
     
  12. milk

    milk Like Verified
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    Well I stand corrected then. 1440p is way beyond "retina" though.
     
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