Patent infringement refers to using a patent without the license or permission of the owner of the patent. If a person uses, makes, sells, or offers to sell a patented product, without the license or permission of the owner of the patent, the person is considered to have infringed the patent and is liable for damages. Patent rights are territorial in nature therefore infringement of a patent occurs only in the country where the patent has been granted.
There are several ways by which a patent may be infringed. They may be direct infringement, literal infringement, infringement by the doctrine of equivalence or indirect infringement.
If a person makes, uses, sells or offers to sell any patented product without the permission or authority of the patent owner, he would be directly infringing the patent. A direct infringer need not have been aware of the patented product at the time of infringement. The only requirement to establish direct infringement is, to show that the infringer made, used, sold or offered to sell a patented product without prior permission regardless of whether he knew of the patent or not. Literal infringement refers to the situation when the claims in the patent read on the infringing product exactly. That is, to establish literal infringement, all of the elements of the claim, as correctly construed, must be present in the accused system. This means that if the patent included a claim that reads on the infringing product, the product would be literally infringed. However, even if the product is not being literally infringed, it is possible that the third party may be still infringing the patent under the Doctrine of equivalents.
According to the law, a patent is literally infringed only when every element of the claims are present in the product. However, the courts have held that even if there is no literal infringement, the patent may be infringed. Furthermore, even if an accused product or method does not literally infringe the claims of a patent, a claim may be infringed under the Doctrine of Equivalents if the accused product or method contains elements identical or equivalent to each claimed element of the patented invention. Under the Doctrine of Equivalents, an element is identical if it performs substantially the same function, in substantially the same way, to achieve substantially the same result. Although, a person may not directly infringe a patent, he may do so indirectly. Indirect infringement is of two types – inducement and contributory. Infringement by inducement occurs when a person actively induces a person to infringe the patent of another. In order to constitute infringement, the inducer must have known of the existence of the patent and known or should have known that his actions would induce actual infringement. Contributory infringement occurs if, a person offers to sell or sells within the country in which the patent is granted or imports into the country in which the patent is granted, a component of a patented machine for use in practicing a patented process and knowing very well that their actions infringe the patent.