5 Comments

Summary:

Back in April, Barnes & Noble one-upped Amazon by introducing the Nook Simple Touch with GlowLight, taking e-ink reading out of the dark. So how did Barnes & Noble get light evenly across the display? It’s not just technology magic, but science that makes it work.

NOOK Simple Touch with GlowLight_Angled
photo: Barnes & Noble

Back in April, Barnes & Noble one-upped Amazon by introducing the Nook Simple Touch with GlowLight, taking e-ink reading out of the dark. The $139 device uses the same infrared touch technology as the prior model, but adds the innovative glowing screen; something not yet found on a Kindle device.

So how exactly did Barnes & Noble solve the problem of uneven light across the display? It’s not just technology magic, but science that makes it work.

Thanks to an iFixit teardown of the device, you can see how Barnes & Noble accomplished this, as well as view all of the many parts packed into the e-reader device. Along the top edge of the e-ink display are eight LED lights, evenly spaced apart.

These are the only lights used make the screen glow evenly and they’re only on the one edge. But the lights don’t shine directly down the display. Instead, the glass display has diffraction grating built-in, causing the light to be spread out across the entire screen surface, says the iFixit blog:

This diffraction grating bends and disperses the light throughout the screen. Barnes & Noble really did their homework on this one, because instead of a simple linear diffraction grating (think of a bunch of parallel slits), it appears that the diffraction grating varies throughout the glass to evenly disperse the light.

To illustrate how the glass display diffracts light across many angles, the iFixit team shined a laser through the screen’s edge. Normally, a laser appears as a single point as all of the light waves are tightly focused. Shining it through the diffraction grating however, shows how the screen spreads a beam of light out.

The solution is ingenious and I’d love to see it come to mobile devices because it would mean using fewer lights and therefore save power. Unfortunately, most smartphones and tablets are backlit, meaning the light comes from under the display, so this is an unlikely prospect for the future. Then again, I’m not a science expert, so maybe there’s an opportunity here!

  1. This is actually exactly how laptops and smartphone are lit. Since the e-ink display can’t transmit light, it’s not “backlit” like laptops/almost all LCD screens with backlighting, it’s instead on the front.

    http://www.engineerguy.com/videos/video-lcd.htm Has an awesome teardown that shows exactly what’s going on.

    Share
    1. Appreciate the info and link, David! Bummer: I thought there was an opportunity here. :(

      Share
  2. m*(lamta)=2*d*sinA,I know the formula of Diffraction grating..
    Thanks for the oppurtunity..
    I like it.

    Share
  3. And here I was thinking it was thousands of pairs of micro-wings from wee angels beating the fire of souls in Purgatory into light.

    Share
  4. Finally. I mean really, I thought the Pods really had taken over in ’56.

    The ebook so far: re-imagine “The Book” with a battery in it, charge me north of $100 for an empty one and dont fix the most important things: poor lighting and distracting others? A common response: “Well, then it wouldnt BE like a book would it?” “That uses up the battery…”

    Um, eek.

    Thank you Barnes & Noble. Time to make these things functional and add value or they are just a historical bookend…

    Share

Comments have been disabled for this post