From code.googleAdditional IP Rights Grant (Patents)
“This design” means the copyrighted book scanner design distributed by Google as part of the "Linear Book Scanner" project.
Google hereby grants to you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, transfer, and otherwise run, modify and propagate this design where such license applies only to those patent claims, both currently owned by Google and acquired in the future, licensable by Google that are necessarily infringed by This design. This grant does not include claims that would be infringed only as a consequence of further modification of this implementation. If you or your agent or exclusive licensee institute or order or agree to the institution of patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that This design or any code incorporated within this
This design constitutes direct or contributory patent infringement, or inducement of patent infringement, then any patent rights granted to you under this License for This design shall terminate as of the date such litigation is filed. https://www.youtube.com/watch?feature=player_embedded&v=4JuoOaL11bw&noredirect=1https://code.google.com/p/linear-book-scanner/