iPad & Retina Display


A Retina Display will make its way into the iPad; I am 100% confident. The question is: when? Only Apple knows, but since it is one of the most secretive companies in the world, all of us outside the core iPad display team will need to guess.

Kevin Rose, founder of Digg:

I have it on good authority that Apple will be announcing the iPad 2 in the next “3-4 weeks”, possibly Tuesday February 1st. The iPad 2 will feature a retina display and front/back cameras.

There is an update citing a another source that the iPad display has a “higher dpi” but is not technically a Retina Display. Of course, that begs the question: what is a Retina Display? I answer the question in iPad 2.0 Gets Retina Display?:

A Retina Display isn’t a hardware specification at all! It is simply a display that has a high-enough resolution when used at the typical “usage distance” that your eyes cannot distinguish individual pixels.

Of course, there is a hardware component to the definition, but it isn’t a rigid hardware specification. The source Rose is referring to probably is working off a different definition of Retina Display. I’d like to stick with my definition as I think it’s closest to what Steve Jobs was referring to when he introduced the Retina Display on the iPhone 4. One comment before I move on: DPI? That’s for printers. For displays it is PPI (Pixels Per Inch).

What would a Retina Display on the iPad look like?

Apple doubled the number of pixels vertically and horizontally on the iPhone 4 compared to previous generation iPhones: 480×320 → 960×640. And Apple will do precisely that with the iPad 2.0: 1024×768 → 2048×1536. The resulting resolution on the iPad 2.0 is 263PPI. That’s far from 300PPI, but you have to remember the “usage distance.”

The number of pixels were doubled vertically and horizontally making the new Retina Display able to display every single previous app flawlessly, albeit with less clarity. Based on the assumption that the iPad has a farther usage distance than the iPhone, the iPad 2’s 9.7-inch IPS LCD with a 2048×1536 pixel format looks like it will qualify as a Retina Display. But is it technically feasible to manufacture such a display?

On the LCD side cramming three million plus pixels into a 4:3 9.7-inch LCD is quite possible: LCD manufacturers are hard at work perfecting the display as we speak, according to my sources. But even if the display was possible wouldn’t it require a powerful GPU, which might consume too much power in the next iPad?

Enter the SGX543 System on a Chip graphics. According to AppleInsider the SGX535 in the current iPad will be replaced by the SGX543, a dual core GPU with 1080p and OpenCL support that offers twice the power of the SGX543. There is also speculation that it could be integrated into a SGX543MP2 with two SGX543 cores for a total of four. The quadrupling in cores and graphics capabilities makes sense since the number of pixels also would quadruple in the iPad Retina Display. I’m not certain about power requirements but if the shift in CPUs from a high frequency single core to lower frequency multiple cores is any indication power consumption shouldn’t increase much, if at all. It seems we have the LCD and the silicon to back it up.

So, will the next iPad have a Retina Display? John Gruber is pretty sure that it won’t:

Rumors are rampant that the upcoming iPad 2 will feature a higher-resolution retina display. Long story short: No, it won’t.

Gruber cites his sources who say: “[...] it is too good to be true [...]” He does mention that the LCD in the iPad 2 will be optically laminated to the cover glass, just like it is with the iPhone 4 bringing the LCD closer to the surface and improving all sorts of things: reduced reflectance, improved brightness, viewing angles, etc. The air gap will be eliminated and gone will be the ritual of pulling your hair out when you notice that dust is stuck in there. Optical lamination of the LCD to the cover glass will also make the iPad 2 thinner.

DigiTimes says that the next iPad will certainly sport a Retina Display:

[...] sources from upstream component makers pointed out that Apple is increasing iPad 2’s resolution to 2048 by 1536 and the new strategy is expected to widen the company’s technology gap with its competitors.

DigiTimes has a spotty record when it comes to conjecturing about future Apple products, but it does have a lot of contacts within the component supply chain for Apple products. As reported on MacRumors, there’s the “iPad 2 LCD Screen” that is being sold on GlobalDirectParts for US$218.19. That’s quite a bit more than the current iPad display for just $63.35. Makes sense since the iPad Retina Display should pack four times the number of pixels.

Avery Pennarun uses Moore’s Law to predict when the iPad will feature a Retina Display. An interesting analysis but his semiconductor knowledge fails to overcome his lack of display expertise:

Each of those successively higher resolution screens was a “new process” in semiconductor speak. With each new process came a higher density of imperfections per unit area, which is why smaller screens were the first to hit these crazy-high densities. We can assume that the biggest screens at “retina” density as of the iPhone 4’s release – 960×640 in June 2010 – was the state of the art at the time. We can also assume that the iPad was the biggest you could go with the best process for that size at the time, 1024×768 in March 2010.

Back in 2005 I had the pleasure of working on Sony’s PCG-TR3AP, which was a 10.6-inch ultraportable notebook PC. There were many other brands with 10.4-inch 4:3 LCDs that packed a 1024×768 pixel format. Sony’s TR3AP featured a 1280×768 pixel format in a 10.6-inch LCD five years ago. Was 1024×768 in a 9.7-inch the best the LCD industry could do in 2010? Absolutely not. But, to get the $499 entry point it was probably the best and only option.

We want to achieve 1024×768 times two = 2048×1536 = (2.13*960)x(2.40*640) = about 5x the physical area of the iPhone 4.

Moore’s law says we get 2x every 18 months. So 5x is 2**2.32, ie. 2.32 doubling periods, or 3.48 years.

By that calculation, we can expect to see a double-resolution iPad 3.48 years from its original release date in March 2010, ie. Christmas 2013.

Christmas 2013? Nah. Interesting analysis, but Pennarun is wrong; 2048×1536 is possible today, in 2011. But does that mean the next iPad will sport a Retina Display? I am not sure, but I will say this: I expect to see an iPad with a Retina Display announcement in 2011.

Oh, remember Kevin Rose at the beginning of this article? He claimed the next iPad would sport a Retina Display. Well, now he claims it won’t. Nobody really knows but Apple. We’ll just have to wait and see. One thing that’s cool about Apple’s product announcements is the suspense and then the, “Surprise!!!”





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