The PTO largely doesn't seem to care or do any research beyond the bare basics. As far as I can tell they're not really incentivised to do so either. They col

The PTO largely doesn't seem to care or do any research beyond the bare basics. As far as I can tell they're not really incentivised to do so either. They collect a whole heap of fees for getting and maintaining a patent (http://www.uspto.gov/learning-and-resources/fees-and-payment/uspto-fee-schedule http://www.uspto.gov/learning-and-resources/fees-and-payment...), and even claim a fee for revisiting a patent, but so far as I've been able to find, it doesn't cost them anything to actually invalidate one. It ought to cost them all the money they've taken so far, and then some on top, to provide them with more of an incentive to make sure the patent is correct.