Nexus screen tech - PenTile, dpi, SAMOLED

[DisplayGeek]

Hi Ms. Elliott, thanks so much for responding!



That doesn't show the 2:1 RGBG subpixel proportions, which would look like:

XXXGXX
XRRGXX
XXXGXX
XRRGXX

XBBGXX
XRRGXX
XBBGXX
XRRGXX

where the yellow vertical is more ragged.



That is impressive! I wish the Nexus' PenTile was an RGBW type.



That sounds counter to what you wrote elsewhere in these forums:

"the distance between the same color subpixel is increased, compared to an RGB Stripe panel, and "pattern visibility", called the "screen-door" effect here, may occur for solid colors. This is one reason why PenTile technology is only recommended for higher resolutions. As displays continue to be spec'ed at yet higher resolutions, this effect will become less of an issue."

but I'm reasonably sure you're right that higher resolutions render the issue moot.

Ah... I see the confusion. Color blending is not the same as pattern visibility. Pattern visibility occurs because the color subpixels are not equal luminosity (brightness difference of colors, green is brightest, blue is darkest). Color blending occurs over a long distance, as the red/green chroma channel tops out at 8 cycles per degree and the yellow/blue chroma channel tops out at only 4 cycles per degree. But the luminance channel goes up to 60 cycles per degree for those whose eyes are still young and healthy. This means that while the colors (chroma information) are fully blended, at lower dpi, the subpixels may still exhibit pattern visibility, but is only visible in the luminance channel, as a grid of grey on white.

Again, the "ragged" edge effect, for those lower dpi panels, seen by young eagle eyes who hold the panels up close... is a pattern visibility issue, not a sharpness issue. Strictly speaking. Paradoxically, "fuzzing" out the panel with an optical filter would actually make it look "sharper" because it would reduce the pattern visibility. (try an experiment with Scotch tape as an optical filter)

 

[Laxstar785]

I have personally never had an issue with the pen tile pixel arrangement on any phones and i have seen them all at least once......I never have a real life case where i have to hold my phone up to my eyeball to the point where its almost touching so i can see granularity and complain about it

 

[DisplayGeek]

Good to know about the actual numbers on that white sub-pixel.

And I never said that the white pixel stopped blending. However, I have observed the greenish yellows and sometimes even 'flyscreening' on the Motorola Atrix. Either that's an inherent problem in RGBW PenTile, or Motorola broke it somehow putting it into their phones.

Since your post came across as somewhat hostile, I'll point out that I'm not some kind of anti-PenTile crusader; I came into this thread defending PenTile.

Sorry... I've spent the past several days explaining (defending?) our latest code for advanced PenTile here in Korea. I'm jet lagged and cranky... and have been reading nasty reviews on the internet regarding Nexus Prime, that have been so far removed from reality, I wonder if they need psych meds.

Our PenTile RGBW code allows for "agressive" power savings modes that sometimes allow for some "simultaneous contrast error" between the white point brightness and saturated colors. In RGBW, we can save more power by reducing the brightness of the brightest fully saturated colors. This can cause bright yellows to appear 'mustard' and greens to appear 'khaki'. If you measure the color, it is still the right color, but compared to the brighter white point, it appears to look different. Color appearance is a VERY complex subject. (Did you know that "brown" is actually "orange"?) Long winded explaination for some of the effects seen on the Moto panels, as they elected to use "agressive" power savings settings at times to extend the battery life.

"Fly screening" is "pattern visibility"... which is most noticed on solid green. That issue will go away as resolutions increase.

 

[2003vstrom]

yeah I have the Atrix 4g with the penTile screen and once in a while I can see the grainy look but it does bother me, I plan on switch from ATT to verzion for GN when it comes out

 

[HanSolo]

Well, I don't know all about the tech speak and such, but BMX just tweeted (in response to someone asking him if the pentile effect was annoying):

I have used both and to be honest I cant tell.. looks great to me and I hated the bionic an droid x2 screens.

 

[2oublethink]

In-depth look at PenTile Screens - PhoneArena

Worry not my friends, you'll all be amazed by the Nexus's screen

 

[SiXiam]

In-depth look at PenTile Screens - PhoneArena

Worry not my friends, you'll all be amazed by the Nexus's screen

If that's true then why are the 30" Dell IPS LCD monitors considered to be some of the very best available?

 

[Sandroidfan]

If that's true then why are the 30" Dell IPS LCD monitors considered to be some of the very best available?

Why do you bring up 30" LCD monitor here?

 

[SiXiam]

Why do you bring up 30" LCD monitor here?

Because people are saying that even though the iPhone 4s screen is better, the larger Galaxy Nexus screen makes up for it. To me that isn't logical with all the flack that inferior screen technology gets in the desktop world.

 

[BlueBiker]

Because people are saying that even though the iPhone 4s screen is better, the larger Galaxy Nexus screen makes up for it. To me that isn't logical with all the flack that inferior screen technology gets in the desktop world.

I disagree. Few people would choose to use a 15" desktop LCD these days, even if it had infinite DPI and amazing colors & viewing angles.

All people are saying is that Nexus is expected to be more than sharp enough for most people while also being large enough to be practical for browsing and other activities that are cramped on a 3.5" display.

 

[sjael]

Sorry... I've spent the past several days explaining (defending?) our latest code for advanced PenTile here in Korea. I'm jet lagged and cranky... and have been reading nasty reviews on the internet regarding Nexus Prime, that have been so far removed from reality, I wonder if they need psych meds.

I totally hear you mate, I've nearly been pulling my hair out over all the bad press that's come up in the last day or so. It's maddening to see that people can be so biased against a technology they haven't even seen yet, and moreso that those in a position of 'power' see fit to distribute their slander to the masses.

Our PenTile RGBW code allows for "agressive" power savings modes that sometimes allow for some "simultaneous contrast error" between the white point brightness and saturated colors. In RGBW, we can save more power by reducing the brightness of the brightest fully saturated colors. This can cause bright yellows to appear 'mustard' and greens to appear 'khaki'. If you measure the color, it is still the right color, but compared to the brighter white point, it appears to look different. Color appearance is a VERY complex subject. (Did you know that "brown" is actually "orange"?) Long winded explaination for some of the effects seen on the Moto panels, as they elected to use "agressive" power savings settings at times to extend the battery life.

Being an artist I know a bit about color composition and things, but that's rather fascinating. Obviously I don't deal with what sounds like some kind of dynamic brightness scaling that RGBW allows for.

"Fly screening" is "pattern visibility"... which is most noticed on solid green. That issue will go away as resolutions increase.

Of this I have no doubt. The Galaxy Note already looks fantastic with RGBG, and I can't wait to see those upcoming 10-inch 2560x1600 RGBW panels.

 

[2oublethink]

Because people are saying that even though the iPhone 4s screen is better, the larger Galaxy Nexus screen makes up for it. To me that isn't logical with all the flack that inferior screen technology gets in the desktop world.

I don't understand... The link explains how great the PenTile screen looks on the Galaxy Note... And you're bringing up a 30'' monitor?

 

[SiXiam]

I don't understand... The link explains how great the PenTile screen looks on the Galaxy Note... And you're bringing up a 30'' monitor?

Because this is so much like a TN vs IPS argument in the desktop monitor arena.

 

[BlueBiker]

Because this is so much like a TN vs IPS argument in the desktop monitor arena.

There are many axes involved: sharpness, color fidelity, viewing angles, power draw, outdoor visibility, purchase cost. No one technology optimizes them all, so different people will choose different compromises.

It's fun to dispute the strengths and weaknesses, but there isn't a right or wrong answer to which display tech is best.

 

[DisplayGeek]

There are many axes involved: sharpness, color fidelity, viewing angles, power draw, outdoor visibility, purchase cost. No one technology optimizes them all, so different people will choose different compromises.

It's fun to dispute the strengths and weaknesses, but there isn't a right or wrong answer to which display tech is best.

+1

There are trade-offs for all engineering decisions: cost vs. performance, color gamut vs. transmittance (for LCD), brightness vs. material lifetime (for OLED), brightness vs. battery life (both LCD and OLED), resolution vs. material lifetime (OLED), resolution vs. transmissivity (LCD), etc. I often say, "pick your poison" because sometimes, ya just can't have your cake and eat it too.

What has interested me in developing PenTile technology for the past twenty years, is that we might be able to make new and better trade-offs, focussing on careful examination of the human vision system, allowing us to trade-off chroma resolution (which the human vision system doesn't need) for more luminance resolution (which we do need) by rearranging the color subpixels and applying digital signal processing.... and in the process, increase the lifetime (OLED) and transmittance (LCD) for a given useful luminance resolution.

It drives me nuts that some people think that PenTile is meant to reduce cost. Rubish !!! It is to improve the information and energy efficiency of color displays. It is designed to enable higher luminance resolution, accellerating the adoption of higher resolution formats. If I had my way, PenTile would be used in much higher resolution formats than presently available. But we must wait until the graphics processors and GUIs catch-up to what resolutions PenTile enables.

Right now, both OLED and LCD PenTile panels use two subpixels per pixel. As resolutions increase, the number of subpixels per pixel may be reduced yet further. One such design uses 1.25 subpixels per pixel, and still meets the VESA spec for resolution. There is even a layout, that also meets the VESA spec, that is only one subpixel per pixel, dispite using five different color primaries (one of them being W), but the resolution must be very, very high for it to work correctly with the human vision system. But, both of these display layouts have challenging subpixels shapes that don't work well with todays display design guidelines, which allow only rectangular shapes and grids. Thus, another engineering trade-off is found in manufacturing limitations.

 

[redraider1]

Like I've mentioned before....forget about 320 ppi if the screen is pentile. GS 2 screen will look better. Really hope that I'm wrong about it being pentile.

It won't look bad. From everyone who has hands on they say the screen is nice and won't be like moto's pentile screens. Not to mention the nexus 1 was pentile and people weren't complaining much then. You just blow it way out of proportion.

 

[Jersey Tom]

Nice to have DG in here explaining things. Much appreciated!

 

[DisplayGeek]

Nice to have DG in here explaining things. Much appreciated!

de nada

 

[Daz655321]

I know talk here has mainly been about the pentile display, but is anyone concerned with Burn-In on the SAMOLED screen? I have seen this first hand on pretty much every samsung phone released on verizon and it might be the biggest worry I have about purchasing the nexus. At my store we have the stratosphere on display and while yes it runs pretty much all day its already suffering burn-in after being out only 2 weeks.

I realize that none of our phones will be running constantly, but 2 weeks is the quickest ive seen for burn-in to take place. I use my phone a lot so my screen is definitely on for more than 1 hour a day from browsing the web, using gps etc.

 

[techrider62]

There's a big differences between a hour and all day

 

[Daz655321]

I know that. But it's pretty common knowledge about burn-in issues with amoled. I know it's a extreme example but even if it's on a couple hours a day for a few months burn in can appear.

 

[Medion]

DG, I appreciate your perspective. However, PenTile in itself is still a trade off. It inherently cannot produce the same quality image as an RGB screen at the same resolution. However, here's the comment that struck me;

It drives me nuts that some people think that PenTile is meant to reduce cost. Rubish !!!

If PenTile displays are cheaper than their RGB counterparts, OEMs will look at them as one possible way to reduce costs. It doesn't matter what the developers of PenTile want, it's what the buyers want. All of the things that you said are great things, but cost is definitely a factor for the OEM.

I have both defended and bashed PenTile displays. Motorola's recent displays (Atrix, D3, X2, Bionic) are straight up trash. There's no way around it. My first encounter with one was when a friend brought me his X2 (he's no videophile, geek, or anything, he just wanted a smartphone), and said "I think my screen is broke." They are THAT bad. However, we also see good PenTile displays, such as the original Galaxy S. Despite that, the SGS2 uses a similar display, but with an RGB layout instead. Guess which one is preferred?

Like you said, PenTile is one of many trade-offs. What we're seeing here is that PenTile is a trade-off that many are becoming more and more aware of, and many don't want to make this trade-off.

 

[ferdasyn]

Like you said, PenTile is one of many trade-offs. What we're seeing here is that PenTile is a trade-off that many are becoming more and more aware of, and many don't want to make this trade-off.

I haven't compared different PenTile displays but based on reviews so far, this seems to be a trade-off that goes away or diminishes with high enough PPI.

 

[Medion]

I haven't compared different PenTile displays but based on reviews so far, this seems to be a trade-off that goes away or diminishes with high enough PPI.

This is correct. My Incredible uses PenTile and it looks very good. The first-gen SGS uses a better PenTile screen at the same resolution, but a larger size and therefore lower PPI, yet still looks vastly superior to the Incredible's screen. It's all about the implementation, and Moto's implementation in their LCD screens was horrendous. PenTile was a bad word to a degree last year, but Moto gave it the scarlet letter this year. If Moto hadn't used PenTile on those phones, no one would care about the RAZR and GN using PenTile.

 

[aentropy]

This is correct. My Incredible uses PenTile and it looks very good. The first-gen SGS uses a better PenTile screen at the same resolution, but a larger size and therefore lower PPI, yet still looks vastly superior to the Incredible's screen. It's all about the implementation, and Moto's implementation in their LCD screens was horrendous. PenTile was a bad word to a degree last year, but Moto gave it the scarlet letter this year. If Moto hadn't used PenTile on those phones, no one would care about the RAZR and GN using PenTile.

I couldn't agree more with Moto and their Pentile screens. The Bionic is TERRIBLE and the pattern is so obvious on the screen. It doesn't look sharp at all and you can see a cross-hatch pattern.

Does anyone have any thoughts on if the Nexus will look even similar to what the Bionic's pentile is? I really hope not, that is the one thing that would keep me from getting it.