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The New iPad's Screen Under the Microscope
- lusr 15y agoMan this guy's got a lot of nice toys. What are the gaps in pixels for? Circuity? Or does it have something to do with the amount of light that needs to be transmitted vs. horizontal/vertical resolution of the eye to represent a square pixel?
- pmjordan 15y agoEach subpixel needs a transistor (hence TFT - thin film transistor) to drive it, along with the addressing conductors to drive it. I suspect the transistors have to have a certain minimum size to be reliable enough, so their relative size to the size of the whole pixel grows with decreasing pixel size. I'm sure they'd make them smaller if they could, as the black areas absorb a lot of precious backlight energy. I also recall reading about progress with making the transistors (which are typically silicon-on-glass) transparent, but I guess that tech isn't ready yet.
- veidr 15y agoLooks great. The iPad screen really has jumped directly from doodoo to voodoo. It would be cool to have the e-ink Kindle on that comparison there, too: http://www.e-ink-info.com/ipad-slcd-vs-kindle-e-ink-close http://www.e-ink-info.com/ipad-slcd-vs-kindle-e-ink-close
- LukasMathis 15y agoGood idea. I've added a picture from a Kindle Keyboard (third gen).
- mladenkovacevic 15y agoI love how the e-ink looks up-close. If only the contrast was higher and in colour. Sadly, I've got a feeling e-ink technology will become extinct.
- LukasMathis 15y agoI think there will always be room for e-ink. This afternoon, I took an hour off to sit on the balcony and read a bit. It was so bright outside that I was barely able to read anything on the iPad. Switched to the Kindle, worked perfectly well. I think it's a technology that fills a niche that LCDs or OLEDs won't fill for a very long time, if ever.
- archivator 15y agoPeople have been experimenting with electrowetting and optional backlights. The results are encouraging - http://news.bbc.co.uk/1/hi/programmes/click_online/8610962.stm http://news.bbc.co.uk/1/hi/programmes/click_online/8610962.s... EDIT: Something more recent - http://www.youtube.com/watch?v=ag4HGceyVik http://www.youtube.com/watch?v=ag4HGceyVik . The colours seem to be lacking contrast but I'm sure that'll be improved as better filters are developed. Mirasol and the like seem to be providing quite a good compromise - http://www.the-digital-reader.com/2012/01/01/review-kyobo-mirasol-ereader/ http://www.the-digital-reader.com/2012/01/01/review-kyobo-mi... That particular reader has the problem of not being as polished as the Kindle but it seems that the screen is rising up to the expectations.
- jrockway 15y agoI don't think so. Tablets are for people that want to get the most possibilities out of their $300. e-ink readers are for people with $300 that want to read books with the least eyestrain. I read on my phone and it just doesn't feel like reading. When I use my Kindle, it does. (I think the problem is actually with page turns rather than the pixels; turning pages on the Kindle Android app is very flaky. On the physical hardware, it works much better.)
- unwind 15y agoIt's painful to see that some people have OpenPandoras, and use them to take reference images to show differences in LCD (and OLED) screen properties. Me, I just want to hold it. Smell it. Feel it. I'm sure I will too, in another 2 months from now. (Explanation: the OpenPandora (http://openpandora.org/ http://openpandora.org/) is a custom portable QWERTY Linux clamshell ultra-console. Or it was, three years ago when I ordered mine. Still waiting for delivery, it's a very small operation and they've had some hiccups along the way.)
- LukasMathis 15y agoI use it for other things, too :-)
- seclorum 15y agoI use mine (I have two) for development mostly. Oh, a bit of MAME with my legal roms too, now and then ..
- rdl 15y agoWould there be a way to demonstrate off-axis viewing capability with the different screen technologies using the microscope?
- LukasMathis 15y agoThe microscope only shows a sharp picture at a specific distance; as soon as you tilt something, most of the picture becomes so blurred that you can't see much anymore. And there's not enough space between the lens and the focus point to really tilt the device much, anyway. Sorry!
- gcheong 15y agoWhat is the microscope that you are using?
- LukasMathis 15y agoA cheap Bresser. Though I wouldn't recommend buying a low-end microscope, like the one I use. You should be able to get much better images by investing just a bit more.
- Gring 15y agoI just unpacked mine. Looks gorgeous. Although, I can still perceive the individual pixels if I look close enough. This is what I expected, because I often hold the iPad at about the same distance as an iPhone, and the iPad has still lower res (326 vs 264 ppi). It's not yet this "device that hides its technology in plain sight beyond any human capability and therefore appears magical". But it's very, very beautiful anyway. Here's hoping that Apple will someday produce a 3x display with 396ppi :-D
- gauravk92 15y agoThey won't, because you wouldn't be able to tell the difference.
- nodata 15y agoFrom ten inches (or less) away you can tell the difference.
- fdkz 15y agoA lot of people will be able to tell the difference. For example I routinely try to read pdf books on my iphone 4 ibooks (without zoom), but it's hard because there are not enough pixels! http://www.displaymate.com/iPad_ShootOut_1.htm http://www.displaymate.com/iPad_ShootOut_1.htm .. Apple’s definition of a “Retina Display” is actually for 20/20 Vision (defined as 1 arc-minute visual acuity). However, 20/20 Vision is just the legal definition of “Normal Vision,” which is at the lower end of true normal vision. There are in fact lots of people with much better than 20/20 Vision, and for almost everyone visual acuity is actually limited by blurring due to imperfections of the lens in the eye. The best human vision is about 20/10 Vision, twice as good as 20/20 Vision, and that is what corresponds to the true acuity of the Retina. So to be an actual “True Retina Display” a screen needs at least 573 ppi at 12 inches viewing distance or 458 ppi at 15 inches. The 326 ppi iPhone 4 is a 20/20 Vision display if it is viewed from 10.5 inches or more. ..
- ugh 15y agoApple doesn't do that kind of stuff. Most people will not be able to see the pixels (at their comfortable viewing distances). That’s good enough for them (also considering they are streets ahead of everyone else in the pixels department).
- odiroot 15y agoIs it only the camera rotation or is Apple switching from BGR to RGB?
- LukasMathis 15y agoIt's just the camera rotation. But it's kind of funny, anyway, since the home button is at the bottom of the screen, so the sub-pixels are arranged top-to-bottom when you hold the iPad with the home button where it should be.
- odiroot 15y agoDoes that affect "crispness" of the fonts? Or maybe they reconfigure subpixel rendering during device rotation.
- LukasMathis 15y agoIt would affect subpixel rendering of fonts, but I think the iPad doesn't do any subpixel rendering. Not 100% sure though. It does create another strange effect, though. Since the screen effectively redraws sideways if you hold the iPad in portrait, scrolling vertically quickly makes stuff look a tiny bit distorted; horizontal lines look a bit slanted (like taking a picture out of a car using a cellphone camera, but much less so).
- Splines 15y agoThat's interesting. I guess Apple decided not to enable vsync? I don't recall seeing tearing playing games on my 4S though, can developers elect to turn it back on?
- LukasMathis 15y agoIt's not tearing, it's just a slightly slanted picture, because the lines on the left (or right, depending on how you hold the iPad) redraw a tiny bit earlier than the ones on the other side of the screen.
- idont 15y agoJust unpacked mine. Gosh... the screen has an issue... As if there was a white-led behind the screen. It appears only on bright colors.
- mrleinad 15y agoFunny there's no comparison with one of Apple's main competitor phones: Samsung Galaxy SII/Note. How about adding that?
- LukasMathis 15y agoNo conspiracy, I just don't have access to these devices. I'll add a Sony Tablet S when I get around to it, though. (Update: I've added the Sony Tablet S image.)
- joering2 15y agolukas thanks for it. Any idea about Nexus One -- how come green pixel is so relatively small. is it just brighter??
- LukasMathis 15y agoNo, that's how PenTile screens work. There are twice as many green pixels as red and blue ones (one "visual" pixel is made up of a green and red pixel, or a green and blue pixel, so there are two sub-pixels per pixel). Thus, the green pixels are smaller.
- SpiderX 15y agoAnd the reason why is because the human eye is more sensitive to green than other colors. http://en.wikipedia.org/wiki/Color_vision http://en.wikipedia.org/wiki/Color_vision
- ypcx 15y agoHave you actually seen an actual display of Galaxy Nexus? There's absolutely no problem that you are describing in the "horrible PenTile OLEDs" link. I've seen an iPhone 4 display, and I can tell you it is worse than the one on Galaxy Nexus.
- LukasMathis 15y ago
- nirvana 15y agoWhat's funny about this is just how distorted the pixels are. Ever since I've understood what displays were (and CRTs before that) I've always imagined this idealized array of perfectly round, very tightly packed red green and blue circles as the pixels. Even looking close (not under a microscope) they look like a grid of squares... not these rectangular things with lots of space between them. They seem to be getting more distorted over time. Maybe when they're so small its less of an issue. I'm surprised at how the red and blue on the kindle fire are so much bigger than the green. The eye is most sensitive to green... yet on the PSP Vita the blue seems to be the smallest of the pixels (meaning the blue pixels will have to put out more light to compensate, or the screen will have a green/red color cast.)
- smackfu 15y agoAre they really distorted though? I wonder if it's an artifact of trying to image a light source, maybe caused by the display not being perfectly level to the microscope stage. I ask because some of the images really do look perfect with sharp edges (the 3DS, the PSP), compared to the blobs of light you see on the other ones.
- LukasMathis 15y agoThe OpenPandora shot doesn't look sharp because it has an anti-glare coating. Some of the others may be a bit too bright for the cheap microscope I'm using, so they're a bit blurry. But mostly, the pixels really do look that way; most of them aren't rectangular at all.
- niels_olson 15y agoThanks for the pics! Since you have these devices and can simply count up the number of pixels and divide by the size of the display, would you please consider photoshopping in scale bars to reflect the length of some unit of measure?
- LukasMathis 15y ago
- jader201 15y agoI inspected the 3rd gen iPad image, trying to figure out roughly how much gap there is between rows, because it looks unexpectedly large. It looks like the pixel-to-gap ratio is about 9:5. This would seem to indicate that the screen is 35.7% black. Obviously, the eye doesn't perceive this large of a gap at no magnification, but still, I was surprised at how much of a gap there is between rows. (Contrast this to the iPhone 4S, which is about 9:3.6, or 28.6% black.)
- ajross 15y agoBut it's a power efficienty issue. The black areas are covering up backlight areas that otherwise would show through as useful illumination. There was a discussion yesterday about this in the iPad teardown thread. I was surprised about the apparent power consumption, and this was posited as one of the reasons.
- Cushman 15y agoShouldn't be surprising, though, right? The same effect that causes you to perceive three colored lines as a single square causes you to perceive a black line as just a somewhat dimmer pixel.
- mwexler 15y agoAny suggestions for a good cheap digital microscope? The author doesn't mention what she or he uses...
- LukasMathis 15y agoMine isn't good, which is why I don't recommend it. But you should be able to find a reasonably good USB microscope at places like Think Geek, or similar gadget sites.
- ajross 15y agoPeople have had reasonable success just taping a webcam on top of a used bench microscope.
- jlgosse 15y agoI just picked one up and I'm kind of disappointed. There are 3-4 specks of dirt under the glass, and with the exception of the amazing display, I'm not sure it's worth the upgrade from the iPad 2. Probably going to return it, and either get my money back or get a device that has a clean display.
- Cushman 15y agoAlmost certainly your local Apple store has a stock reserved for replacements-- you should be able to walk in, show it to them and walk out with a new device.
- ricardobeat 15y agoIf the rows of pixels weren't far apart, visible pixels wouldn't be square.
- jader201 15y agoThat's not true at all. Maybe for the given shape of the pixels on these displays, but as a general statement, this is false. If you have red, green, and blue subpixels that have exactly a 3:1 height-to-width ratio -- thus forming a perfect 1:1 square -- then you could have zero black space on all sides, and the pixels would appear perfectly square.
- joshu 15y agoHuh! I JUST bought a stereomicroscope. I should try looking.
- kirbysayshi 15y agoAny chance you have a Motorola Droid (1st one) hanging around? I'd love to see how that screen compares. It was near-retina, at least by the look of it, and I think was AMOLED (since you mentioned the Nexus One).
- LukasMathis 15y agoNope, don't have one of these, sorry.
- nooneelse 15y agoAccording to my calculations from a year ago, the Motorola Droid would be a "retinal" display at a viewing distance of 12.45 inches.
- Raphael 15y agoIt's LCD, 265 PPI.
- kirbysayshi 15y agoAh, my mistake, I should have looked first. Honestly, it was a beautiful screen.
- tocomment 15y agoIf you just make the pixels 100 times smaller you could have a holodeck. Source: http://www.phased-array.com/1996-Book-Chapter.html http://www.phased-array.com/1996-Book-Chapter.html
- kimwim42 15y agoIt looks like Nintendo 3ds screen is made from lego.