

Nexus One display and subpixel pattern - jonknee
http://blog.javia.org/nexus-one-display-and-subpixel-pattern/

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romland
I consumed this article with much enthusiasm. It was filled with information
and still very easy to read.

My immediate thought though: I wonder how much battery-time you would gain by
making the device monochrome (black/green) when you just intend to use it to,
say, call or perhaps even read something.

Maybe a mode like this already exists in Android? I don't have a Nexus one,
so... :) Heck, if it doesn't exist, then I guess this might be an app for the
Android app-store. Send me a cookie if you write one!

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mortenjorck
I still want to see some real numbers on energy consumption between a 100%
white and 100% black (but still powered) AMOLED. As the first two letters
stand for active matrix, there's still a control voltage going through each
pixel when it's at RGB000, so the difference may not be as great as it's often
made out to be.

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GeorgeTirebiter
I put an ammeter on my Nexus One and measured 160 ma in black screen, and
about 450 ma in white screen (with a "flashlight" application).

When on but screen powered down (normal "waiting for a call" mode) I measured
2 ma, average, with occasional blips much higher (to 400 ma, measured with a
Fluke 87 in MIN/MAX mode).

When powered "off" the phone takes 60 uA - I attribute this to keeping an
internal RTC active, possibly keeping some sort of pseudo-static RAM active -
but those are just guesses.

The battery voltage measured 4.1

I did these current measurements by wedging in two thin pieces of copper tape
with an insulator in between, placed between the + battery terminal and the
phone's + input.

The phone indicated "4 bars" and Edge service (not 3G) when I made these
measurements.

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amvp
Kudos for actually making the effort to take the measurements. Thank you

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amichail
I was actually happy with the display in my 2nd generation iPod touch. Note
the past tense. I shouldn't have clicked on this link...

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bmalicoat
That's actually pretty interesting. I wonder if it was hard to do a subpixel
rendering system for fonts (like ClearType)? I don't have a Nexus One so maybe
the pixel density is high enough that they don't need to render fonts like
that.

~~~
Tuna-Fish
Actually, it does make it hard. To do subpixel smoothing correctly, you need
to be able to keep the total amount of color the same -- so if you want to
move a part of the glyph right one, you'd light up a red from the next pixel
right and turn off blue on the last pixel in your line on the left. This
becomes both much harder and less useful when not all pixels have all colors.

But you are right on the other point -- at 800x480 on a 3.7 inch screen has a
ppi of 250 -- or just normal font rendering looks as smooth as subpixel
rendering on a computer screen, and I for one would be hard pressed to
distinguish between subpixel rendering and normal when looking at text at size
10 or so on that screen -- just because I'd have such a hard time seeing it at
all.

I wish we could get proper OLED computer screens.

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fortybillion
From what I understand, the iPhone doesn't use sub-pixel font rendering
either, because of the high pixel density (which is not even as high as the
Nexus One).

Since the display rotates, normal desktop sub-pixel rendering algorithms won't
work anyway.

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hexley
I have heard that OLED screens are extremely difficult to read in
daylight/direct sunlight, can anyone confirm or deny this? I think this would
be a problem in on a phone in some places.

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arantius
I have, to date, had zero trouble using my N1 phone anywhere yet. Two key
points:

1) It's winter in New York City. Even outside there's not a lot of really
bright sunlight.

2) The N1 has a feature (which I like) whereby, with a light sensor, it
adjusts the brightness of the screen to compensate for ambient light
automatically. Or: readable in light, not blinding at night.

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joshu
Interestingly, many camera sensors also have a dithered sensor pattern:
<http://en.wikipedia.org/wiki/Bayer_filter> \- but a different arrangement of
colors.

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ars
Yah. That's almost exactly the same pattern, just with the red and blue
swapped.

This phone should be great for displaying raw images, since you can show the
subpixels with a one to one relationship.

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snprbob86
Very interesting! This may explain the un-Googley-ness of the Android
interface. I was racking my brain to figure out why the interface didn't have
a blue, Gmail mobile /web app look and feel.

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mortenjorck
It's an interesting connection to make, but I don't think OLED subpixel
operating life estimates played a part in the UI design. Remember, wherever
there's a white pixel, there's a blue subpixel going at full strength, and
there's no shortage of white in Android.

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jws
800 horizontal pixels, but half of them can contain no red and the other half
can contain no blue. Someone should cue the lawyers from the dithered LCD
lawsuits. They will have a field day with this.

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ars
That's not accurate. The human eye uses primarily green to detect resolution.
Red and blue are used for color.

I wish I could find it, but there was an online example, where someone took a
picture, divided it into the three channels, then pixelated (mosaic) one
channel at a time and recombined it.

When he did green you saw it right away. With red it took some pixelation
before you could see it. And with blue it took a LOT of pixelation before you
noticed anything.

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rbabich
"Your eyes suck at blue": <http://nfggames.com/games/ntsc/visual.shtm>

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ars
Thank you! I've been looking for that page for so long.

