Friday, August 27, 2010

For eBook Reading Devices, More is Less

If you've been following the evolution of ebook reading devices, you will have noticed a recent wave of new products and price reductions; for a review see this article. I've been interested in two intertwined questions: "How low will prices go?" and "How will reading devices evolve?

In my previous look at reader prices I showed a graph of historical pricing versus time and predicted that we'd see $25 e-readers in 2014; here's an updated graph. In this version, I've connected the pricing for particular devices to help unravel the tangle of lower prices vs. more features. What you can see is that the cheapest devices continue to get cheaper; we're on track to see $50 devices in 2012. At the same time, we see a a full range of devices emerging, with full color, video and gaming capable devices like the iPad occupying a price point of about $500 and adding functions instead of cutting price.

The latest Kindle exemplifies the evolution of the dedicated reading device. David Pogue's review in the New York Times suggests that its biggest improvements are things that have gone away- weight, area, and cost. It's quite possible that this trend will continue, but it's also possible that reader prices will stabilize and instead add features like touch screen, color, and video support.

Since the reader device evolution is determined in many respects by the display, I reached out to some contacts is the display industry to better understand what to expect over the next few years. What I learned was that, at least for the next year or two, the very best reading experience will be delivered by single-function, reading-focused devices.

The display technology behind the Kindle and its competitors from Sony, Barnes and Noble, Kobo, and the real-soon-now Copia is called e-ink. E-ink displays use electric fields to push black stuff to the surface of the display. These displays consume power only when the page is refreshed. They're too slow to do video, but the very low power consumption allows the reader to use a small, light-weight, long-lasting battery. They rely on reflected light, just like real ink on paper, and display manufacturers struggle to make the reflectivity of the white part as high as possible. White paper reflects about 85% of the light that hits it; black ink reflects only 20%. For comparison, the "white" part of an e-ink display reflects 40% of the incident light.

Since I've gotten used to the iPhone, the Kindle's lack of a touch screen bothers me. But the addition of a touch screen reduces the readability of text in two ways. Touch screens are extra layers that sit on top of a display. This extra layer includes a conductive layer made of a material called indium tin oxide (ITO). Although ITO is mostly transparent, it still absorbs about 10% of the light that goes through it. That means that the white part of an e-ink display with a touch layer is down to about 34% reflectance, which is closer to black ink than white paper. The touch layer also separates the pixel from the surface of the display; imagine the effect of reading a book under a thin layer of yellowish glass.

Nontheless, e-ink readers with the touch feature don't look so bad; the Sony PRS-600 Reader Touch Edition is one such device (currently retailing for about $150). Touch layers also a impose a power penalty; a device has to be constantly checking to see if there's a finger poking at it. The cost of adding a touch layer is significant; the yield of the attachment process is not 100%, the display is the most expensive part of a reader. However you slice it, a non-touch device will be easier to read than one with touch.

It's a similar story with color. Color displays require either multiple layers or extra pixels. There will be a severe tradeoff between the readability of a display and its color capability.

Reader manufacturers are addressing these tradeoffs in various way. Apple uses a hefty battery powering a bright backlight to achieve acceptable performance in the iPad; they've been able to save lots of power with a custom processor, and the iPad's operating system and App Store impose severe constraints on what the iPad will run. The Nook has separate displays for reading and for color/touch; I find the result to be a bit clunky. The new Pixel Qi displays offer multiple display modes- the reflective black and white mode offers low power and good readability, while, a backlit mode offers color and video speed.

Right now there's no reason for Amazon to push its price point; the $139 Kindle is back ordered, and it appears that they're selling as fast as they can make them. E-ink displays are manufactured by a single company that has the ability to manage supply to avoid a margin-killing glut of displays. You can expect Amazon to drop the price even further as soon as its supply allows; its long term strategy is clearly to make money selling ebooks rather than reader devices.

After the iPad came out there have been all sorts of predictions of the imminent demise of the dedicated e-reader. My look at current technology suggests that, at least for the next few years, the best reading experience will be delivered by simple, cheap, dedicated reading devices, and the business models for ebook sellers will likely center around content and forms of interaction that work well on slow, black and white displays.

I'm still going to buy an iPad, though!
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