[Philip Lelyveld comment; Innovation is never stifled, it is only (re)directed by business, legal, tech, and social influences. This expiring patent that 'held back innovation' was the largest source of revenue for a group at UT Austin, hardly a patent troll org.]
In February 2014, key patents that currently prevent competition in the market for the most advanced and functional 3D printers will expire, says Duann Scott, design evangelist at 3D printing company Shapeways.
These patents cover a technology known as “laser sintering,” the lowest-cost 3D printing technology. Because of its high resolution in all three dimensions, laser sintering can produce goods that can be sold as finished products.
See the full story here: http://qz.com/106483/3d-printing-will-explode-in-2014-thanks-to-the-expiration-of-key-patents/