Interesting research from Disney Research,
explores using 3D printing with custom optical elements for interactive devices.
This embeds sensing, display and illumination features into the body of a device using Light Pipes printed with optically clear material.
(original link at: http://www.youtube.com/watch?v=eTeXTbXA6-Y).
Read more about the project and some potential uses at
or read the research paper Printed Optics: 3D Printing of Embedded Optical Elements for interactive Devices at
Other Useful Links:
Light Pipes: http://en.wikipedia.org/wiki/Light_tube
LED light Pipes: http://www.toby.co.uk/content/catalogue/series.aspx?category=87