Doctrine of equivalents

Cross-referenced

Infringement

The unauthorized making, using, selling, or importing of a product or process that falls within the scope of a valid patent's claims. Infringement is determined by comparing each element of a patent claim to the accused product or process. If every element is present — literally or under the doctrine of equivalents — infringement exists.

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Literal infringement

Infringement where the accused product or process contains every single element of a claim exactly as written. If even one claimed element is missing there is no literal infringement, though the doctrine of equivalents may still apply.

Cross-referenced

Claim

The numbered sentences at the end of a patent that define exactly what is legally protected. Claims are the only part of a patent that determine infringement — if a product or process doesn't fall within the scope of at least one claim, there is no infringement. Every other part of a patent (abstract, drawings, specification) exists to support and illuminate the claims.

Cross-referenced

Patent

A government-granted right that gives an inventor the exclusive right to prevent others from making, using, selling, or importing a patented invention within the country that granted the patent, for a limited time. A patent does not give the owner the right to practice the invention — only the right to exclude others. The US issues three types: utility, design, and plant patents.

Declaratory judgment

A lawsuit in which a company that fears being sued for infringement asks a court to rule first — typically that it does not infringe, or that the patent is invalid. It lets an accused party control the timing and forum instead of waiting to be sued.

Double patenting

A rejection that stops an inventor from getting two patents for the same invention, or for an obvious variation of it. The common obviousness-type double patenting is usually overcome with a terminal disclaimer that ties the two patents' expiration dates together.