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Sharp's 4K Smartphone Display Highlights OEM Tradeoffs

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So there are already 5.5" 4K screens, but I still can't get a 24" 4K monitor?
There talking about other countries doing this like Korea. Korea is usually close to a year ahead of us technology wise. which is why they already are introducing 4k into the mainstream.


Sep 26, 2013
I am actually glad they accomplished it as this will finally end ridiculous PPI race on smartphones as even those with best eye sight among us can't see even this much. To be honest with you 300 PPI is considered as a good photography quality what is exactly that 5"(4.8") 720p is delivering.


Apr 27, 2013
Depending on the usage, this is either stupid, or good.

If its for a phone its dumb. Your eye cant see that many pixles, 1080p(or varients) are just about perfect for the distance you will hold a 5.5" screen phone. Even if it wasnt dumb for a phone, i wouldnt want it with current hardware, it would be too slow.

If we are talking a screen for a virtual headset tho, then 4k at that size is about what you need. Tho 3 inches from your eyes, you might need more like 8k.

A 10" ish screen for a tablet at 4k, would probably be about fine. Tho, i wouldnt want 4k in a tablet with current hardware, would be too slow.
A couple years ago people were doubting 4k's usefulness as a television screen. Now we are seeing 4k smartphones coming up.

Well, it's good to improvise, but the returns do diminish. I'd love to see better cameras on smart phone instead.

Doug Lord

Jan 8, 2014
1080p is all you need in a smartphone. I would only be interested in 4k for a tablet or desktop. I have no interest in anything in between because their is no native media for 1440p. Much more interested in seeing HDR, Rec 2020 etc...

It's not the screen resolution or PPI which matters. It's the angular resolution. 20/20 vision is the ability to distinguish a line pair with one arc-minute of separation (1/60th of a degree). That is, both the PPI and viewing distance matter. For a printout viewed at arm's length (approx 24 inches), that's 1 / (24 inches * tan ( 0.5 * 1/60 degree )) = 286 PPI, which is where that 300 PPI figure for "good photographic quality" comes from. Likewise, 4k on a 50" TV is useless when viewed from further than about 8 feet. But on a 30" monitor viewed from 3 feet it's a marked improvement over 1080p.

If you hold the display closer than 24 inches away, then your eyes are capable of resolving higher than 300 PPI. So yes, those 400 and 500 PPI phone disiplays do provide some benefit since often people hold them closer.

800 PPI is starting to get ridiculous though (unless you've got a magnifier put in front of it). The only use I can see for that is to compensate for (lack of) subpixel rendering on a RGB stripe. Pentile RGBG is symmetric vertically and horizontally. So the same subpixel rendering algorithm works in both landscape and portrait mode, and you don't need to get to ridiculous PPI to fully fool the eye.

RGB stripe is asymmetric. When you do subpixel rendering on it, the effective horizontal PPI ends up being 3x greater than the vertical PPI (for monitors). That is, a 300 PPI display with subpixel rendering has 900 addressable PPI horizontally, but only 300 addressable PPI vertically. For a handheld device that's flipped between landscape and portrait mode, this corresponds to the display being different (markedly worse in resolution) in the horizontal or vertical direction depending on the orientation of the display. One way to counteract this would be to move up to something like 800 PPI - vast overkill in one axis in order to compensate for a shortcoming in the other axis.

Or you could just use the simpler and cheaper solution - switch to a subpixel array which is symmetric in both directions, like Pentile RGBG.


Jul 28, 2013
I'm waiting for call audio quality to become better... the original purpose of the phone. I don't think I will see that any time soon, with things like 4k screens coming out.


Mar 14, 2015
Cellphones needs at least double the ram they currently spec them with, a way to dock them with monitor & keyboard & mouse & charge at the same time; and they need better operating systems with much more control over the processes & services that are running (or not running because they keep getting killed off by low memory...).

They don't need another gimmick that does nothing to address their current functioning being sub-par.


Jan 12, 2011
On a 1080p screen with normal use, I can discern pixels. With 1440p, that discernment goes away and is wonderful to use. 4k, short of doing VR, is overkill (but then, who wouldn't want to pop their phone into a VR kit and give it a go, even for the gimmick?)


Apr 1, 2004

Easily :)

And 16K in 24" would be next in the line... or something similar. But yeah, battery life is more important after certain pixel intensity.

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