For those of you who deride Pentile and worship RGB, here's why Pentile is better. Look at the top picture. Which direction is the top of the phone? Is it left/right? Or up/down?
You can't tell because Pentile is symmetric along both axes. One row is RG, the next row is GB. Just as one column is RG, and the next column is BG. That means you can do subpixel rendering along both axes, and you can do it with the same algorithm. Flip your phone/tablet into landscape or portrait mode. Doesn't matter - the subpixel rendering works both ways.
RGB subpixel arrangements can only do subpixel rendering along one axis (usually horizontal). That means a 1920x1080 display using RGB is effectively 5760x1080 with subpixel rendering, with a 1:3 subpixel aspect ratio. You get three times the effective resolution along one axis as you do the other.
Our eyes don't work like that. They have the same resolution in the vertical as in the horizontal. Which is why Pentile can better match the eye's resolving power using fewer subpixels. And why eventually Pentile will beat out RGB.
I believe pretty much every RGB device has left to right subpixels when in portrait, so that would actually be 1920x3240. In any case, I do see your point about subpixel rendering in both directions; the issue is that the pixel model we use really doesn't support Pentile, so practically the antialiasing looks pretty bad. But with Samsung so influential, I wouldn't be surprised if that changed.
The point is --- does it matter for modern devices? iOS did not use subpixel rendering at first, and and as far as I know STILL does not. (For the reason described --- you can only make it work as expected in two of the four orientations.)
If the company that, arguably, cares the most about the appearance of its screen thinks sub-pixel rendering no longer matters once you hit modern screen densities, maybe it's time to treat it as an interesting (but obsolete) piece of technology trivia from the past --- just like we no longer spend time worrying about the optimal way to dither a 24-bit image to an 8-bit screen.
If Pentile definied a RGBG 2x2 group as a pixel, that would be fine. But that's not what happens. A single RG or BG pair is defined as a subpixel. Each addressable pixel on a Pentile display CANNOT produce an output in the full gamut.
It's largely irrelevant because the human eye can pretty much not distinguish color on the detail level of pixels. The "retina" threshold for the ability to tell apart colors lies at a way lower dpi than that for luminatic information. Hence why pentile is almost a battery life, heating and production cost free lunch.
How about taking similar pictures (preferably in scale) of Galaxy Note 3 screen and this one? I'm mostly interested in seeing how things are shaping up from the perspective of Oculus Rift DK1 / DK2 owners, who are interested in seeing how the future is shaped to be.
It seems like we will be living our lives trough diamond shaped screen door effect for the next year or two...
Can somebody explain to me how this is pentile? I just see a normal RGB bayer mosaic when I look at this photo, i.e. groups of four pixels with 2x green on one diagonal and red and blue on the other diagonal
Ah, I understand my confusion, LCD's do not use a bayer pattern, but a stripe pattern.
Quote from the wiki page about the Pentile_Matrix_Family: "Thus the RG-BG scheme creates a color display with one third fewer subpixels than a traditional RGB-RGB scheme but with the same measured luminance display resolution.[5][6] This is similar to the Bayer filter commonly used in digital cameras."
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Death666Angel - Friday, August 29, 2014 - link
I don't see the unevenness. But that is one weird picture! :DJoshHo - Friday, August 29, 2014 - link
It definitely takes close examination but you can see how the shapes are a bit jagged and they can have some size variation as well.tuxRoller - Friday, August 29, 2014 - link
For comparison's sake, what's the typical variance of an lcd subpixel?JoshHo - Friday, August 29, 2014 - link
The line edge roughness issue is something I haven't seen in LCD.soccerballtux - Saturday, August 30, 2014 - link
I have a better idea for what to do with my saturday!Solandri - Friday, August 29, 2014 - link
For those of you who deride Pentile and worship RGB, here's why Pentile is better. Look at the top picture. Which direction is the top of the phone? Is it left/right? Or up/down?You can't tell because Pentile is symmetric along both axes. One row is RG, the next row is GB. Just as one column is RG, and the next column is BG. That means you can do subpixel rendering along both axes, and you can do it with the same algorithm. Flip your phone/tablet into landscape or portrait mode. Doesn't matter - the subpixel rendering works both ways.
RGB subpixel arrangements can only do subpixel rendering along one axis (usually horizontal). That means a 1920x1080 display using RGB is effectively 5760x1080 with subpixel rendering, with a 1:3 subpixel aspect ratio. You get three times the effective resolution along one axis as you do the other.
Our eyes don't work like that. They have the same resolution in the vertical as in the horizontal. Which is why Pentile can better match the eye's resolving power using fewer subpixels. And why eventually Pentile will beat out RGB.
Crash course on subpixel rendering:
https://www.grc.com/ctwhat.htm
sheh - Friday, August 29, 2014 - link
The main job a display has to do is display whole pixels. Subpixel AA is just a bonus. I find non-RGB displays look worse given similar DPI.marcustyphoon - Friday, August 29, 2014 - link
I believe pretty much every RGB device has left to right subpixels when in portrait, so that would actually be 1920x3240. In any case, I do see your point about subpixel rendering in both directions; the issue is that the pixel model we use really doesn't support Pentile, so practically the antialiasing looks pretty bad. But with Samsung so influential, I wouldn't be surprised if that changed.name99 - Sunday, August 31, 2014 - link
The point is --- does it matter for modern devices?iOS did not use subpixel rendering at first, and and as far as I know STILL does not. (For the reason described --- you can only make it work as expected in two of the four orientations.)
If the company that, arguably, cares the most about the appearance of its screen thinks sub-pixel rendering no longer matters once you hit modern screen densities, maybe it's time to treat it as an interesting (but obsolete) piece of technology trivia from the past --- just like we no longer spend time worrying about the optimal way to dither a 24-bit image to an 8-bit screen.
tuxRoller - Friday, August 29, 2014 - link
At high enough dpi you can simply drop subpixel aa. Some phones are at that point (that newish lg phone with 530dpi).edzieba - Saturday, August 30, 2014 - link
If Pentile definied a RGBG 2x2 group as a pixel, that would be fine. But that's not what happens. A single RG or BG pair is defined as a subpixel. Each addressable pixel on a Pentile display CANNOT produce an output in the full gamut.jann5s - Monday, September 1, 2014 - link
an RG or BG pair is defined as a subpixel? or did you mean as a pixel?Rdmkr - Monday, September 1, 2014 - link
It's largely irrelevant because the human eye can pretty much not distinguish color on the detail level of pixels. The "retina" threshold for the ability to tell apart colors lies at a way lower dpi than that for luminatic information. Hence why pentile is almost a battery life, heating and production cost free lunch.jann5s - Monday, September 1, 2014 - link
do you have a reference which details this more, I think this is very interestingRdmkr - Monday, September 1, 2014 - link
I don't have a very good resource on the ready but the wikipedia page http://en.wikipedia.org/wiki/Chroma_subsampling is a good place to start. See also the pictures in http://en.wikipedia.org/wiki/Chrominance and http://en.wikipedia.org/wiki/YCbCr. Pentile exploits the same principle as chroma subsampling.sheh - Friday, August 29, 2014 - link
I hope aperture ratio is going to get more attention. Maybe VR goggles will help with that if they end up becoming common.In distances up to normal desktop usage I find the gridlike-look of LCDs disturbing.
boozed - Saturday, August 30, 2014 - link
The resolution of the "on" photo seems too low to tell whether the variability is truly in the display, or merely aliasing in the photo.JoshHo - Sunday, August 31, 2014 - link
That's true, I'm looking into getting an improved microscope for this purpose. However, the off photo shows it quite well.zepi - Sunday, August 31, 2014 - link
How about taking similar pictures (preferably in scale) of Galaxy Note 3 screen and this one? I'm mostly interested in seeing how things are shaping up from the perspective of Oculus Rift DK1 / DK2 owners, who are interested in seeing how the future is shaped to be.It seems like we will be living our lives trough diamond shaped screen door effect for the next year or two...
jann5s - Monday, September 1, 2014 - link
Can somebody explain to me how this is pentile? I just see a normal RGB bayer mosaic when I look at this photo, i.e. groups of four pixels with 2x green on one diagonal and red and blue on the other diagonaljann5s - Monday, September 1, 2014 - link
Ah, I understand my confusion, LCD's do not use a bayer pattern, but a stripe pattern.Quote from the wiki page about the Pentile_Matrix_Family: "Thus the RG-BG scheme creates a color display with one third fewer subpixels than a traditional RGB-RGB scheme but with the same measured luminance display resolution.[5][6] This is similar to the Bayer filter commonly used in digital cameras."