§ 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.

U.S. Code

§ 288. Action for infringement of a patent containing an invalid claim