Canon Imaging showcases a very interesting flash on their Japanese site.  The interactive flash site explains the Technology of L, Canon’s EF Lens L-series line up and also provides downloads for some high resolution wallpapers.

Canon EF L Series Main Page

The Technology of L
The Canon L-series of EF Lenses incorporates specialized optical material such as synthetic fluorite, Super UIF and UD glass, and large-aperture high-precision aspherical lens. These terms are further explains in this very user friendly flash based site.

Canon 70-200 F4L IS USM Lens Assembly

The Technology of L includes optical technology, lens mount, drive technology and also the technology Canon uses for durability and toughness of their L lenses.

Super Spectra Coating on L series Lens

Canon Image Stabilizer

Weatherproof Built