Patent Infringement Opinions
Under United States law, an infringement may occur where the defendant has made, used, sold, offered to sell, or imported an infringing invention or its equivalent.
No infringement action may be started until the patent is issued. However, pre-grant protection is available under 35 U.S.C. § 154(d), which may allow a patent owner to obtain reasonable royalty damages for certain infringing activities that occurred before patent's date of issuance. This right to obtain provisional damages requires a patent holder to show that:
(1) the infringing activities occurred after the publication of the patent application,
(2) the patented claims are substantially identical to the claims in the published application, and
(3) the infringer had "actual notice" of the published patent application.
Direct infringement
A person directly infringes a patent by making, using, offering to sell, selling, or importing into the US any patented invention, without authority, during the life of the patent.
Indirect infringement
In the United States there are two types of "indirect infringement" / "contributory infringement" and "induced infringement."
In the United States, 35 U.S.C. § 271(b) defines (active) induced infringement: "Whoever actively induces infringement of a patent shall be liable as an infringer."
Also in the United States, 35 U.S.C. § 271(c) defines contributory infringement. It provides that "Whoever offers to sell or sells within the United States or imports into the United States a component of a patented machine, manufacture, combination, or composition, or a material or apparatus for use in practicing a patented process, constituting a material part of the invention, knowing the same to be especially made or especially adapted for use in an infringement of such patent, and not a staple article or commodity of commerce suitable for substantial non-infringing use, shall be liable as a contributory infringer."
Active inducement of infringement
Under 35 U.S.C. § 271(b), "whoever actively induces infringement of a patent shall be liable as an infringer." Thus, by selling products that only has use if used in an infringing way, the seller could be found liable for the direct infringement of the end user. This provision typically protects against those who aid and abet end users. National Presto Indus., Inc. v. West Bend Co., 76 F.3d 1185, 1195 (Fed. Cir. 1996). Further, there can be no inducement if there is not first a showing of direct infringement. Fuji Mach. Mfg. Co. v. Hover-Davis, Inc. 60 F.Supp. 2d 111, 117 (W.D.N.Y. 1999).
Defenses Invalidity and Non-Infringement
Typical defenses to patent infringement is to attack the validity of the patent and claim non-infringement. Even if the patent is valid, the plaintiff must still prove that every element of at least one claim was infringed and that such infringement caused some sort of damage. In case of a medical procedure patent issued after 1996, a U.S. infringer may also raise a statutory safe harbor defense to infringement. It is common for defendants to file inter partes Reexaminations or Ex Parte Reexaminations in an attempt to invalidate or narrow the asserted patent.
Remedies
Under US law, a patent owner is entitled to the larger of either a reasonable royalty or lost profits that result from infringement of their patent. Reasonableness is determined by the standard practices of the particular industry that the invention is in. Lost profits are determined by a "but for" analysis. (e.g. "My client would have made X dollars in profit but for the infringement of his/her patent.")
If an infringer is found to have deliberately infringed a patent (i.e. "willful" infringement), then punitive damages can be assessed up to three times the actual damages. Legal fees can also be assessed.
An infringer can also be enjoined from further infringement of the patent, even to the point of being forced to remove an infringing product from the market.
Freedom to Operate and Clearance Opinions
Because willful infringement can be so costly, it is highly recommended to obtain either a non-infringement or invalidity opinion from a patent lawyer if you are unsure whether you are be engaging in infringing activity.
The patent lawyer will conduct a clearance search on issued patents or on pending patent applications to determine if a product or process infringes any of the claims of the issued patents or pending patent applications. A clearance search is normally followed by a clearance opinion, i.e. legal opinion provided by one or more patent lawyers as to whether a given item or process infringes the claims of one or more issued patents or pending patent applications. Clearance opinions may be done in combination with a "validity and enforceability" opinion. A validity and enforceability opinion is a legal opinion as to whether a given patent is valid and/or enforceable.