35 U.S.C. 288 Action for infringement of a patent containing an invalid claim.
Whenever, without deceptive intention, a claim of a patent is invalid, an action may be maintained for the infringement of a claim of the patent which may be valid. The patentee shall recover no costs unless a disclaimer of the invalid claim has been entered at the Patent and Trademark Office before the commencement of the suit.
Effective Dates for Changes Made to this Section
REMOVING DECEPTIVE INTENT
Section 20 of the America Invents Act
(l) EFFECTIVE DATE.--The amendments made by this section shall take effect upon the expiration of the 1–year period beginning on the date of the enactment of this Act and shall apply to proceedings commenced on or after that effective date.