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[* black] The glass over the E-ink screen takes the light from the eight LEDs at the top and evenly distributes it.
[* black] How you ask?
[* black] Optics. The glass is specially designed using two principles of optics: internal reflection and diffraction.
[* black] Light coming from the LEDs goes into the glass which has a [http://en.wikipedia.org/wiki/Diffraction_grating|diffraction grating] on it. This diffraction grating bounces the light around using internal reflection. Barnes and Noble really did their homework on this one, because instead of a simple linear diffraction grating, the diffraction grating seems to change throughout the glass to compensate for the local conditions.
[* black] How do we know its a diffraction grating?
- [* black] [http://shaktronics.com/files/2010/02/big-scary-laser.gif|Lasers]. We took a laser and pointed it at the glass. Unlike the light of the white LEDs found on the nook, the laser has a very limited wavelength, so when you shine it through the glass you see the diffraction pattern in the picture.
+ [* black] [http://shaktronics.com/files/2010/02/big-scary-laser.gif|Lasers]. We took a laser and shined it though the glass panel onto the wall. Unlike the light of the white LEDs found on the Nook, the laser has a very limited wavelength, so when you shine it through the glass you see the diffraction pattern in the picture projected onto the wall.