This is termed as the "notice function" of a patent claim—to warn others of what they must not do if they are to avoid infringement liability.
Before that time, it was often difficult to decide whether a product infringed a patent, since the sole basis to know the extent of protection was the description, in view of the prior art.
The first person who used in a US patent application the term "claim" in its current meaning is believed to be Isaiah Jennings in 1807.
[8] In recent years,[vague] Japan's system has become more peripheral,[9] while the system used in the United States was becoming more central because of the increasing resort in US patent litigation to the doctrine of equivalents to expand claim scope unpredictably,[10] until the US Supreme Court reversed that trend in the Warner-Jenkinson case in 1997.
[12] Under the European Patent Convention (EPC), a claim must define the matter for which the protection is sought in terms of technical features.
In an independent claim in Europe, the preamble is everything which precedes the expression "characterized in that" or "characterized by" in a claim written according to the so-called "two-part form", and therefore everything which is regarded as known in combination within one prior art document, namely the closest prior art document.
In light of the "excess claim" fees currently imposed by the USPTO, this tactic can quickly become expensive.
[28] Notably, printed matter (including data stored on a computer drive)[29] and signals (such as transient electromagnetic waves, (see in Re Nujten).
Three US Supreme Court justices (Sonia Sotomayor, Ruth Bader Ginsburg, and Stephen Breyer) in their concurring opinion in Alice Corp. v. CLS Bank International suggested, that all business methods should be excluded from patentability: "[A]ny claim that merely describes a method of doing business does not qualify as a process under § 101.
Certain words commonly used in claims have specific legal meanings determined by one or more court decisions.
For instance, the word "comprises", when used in the claims of a United States patent, means "consists at least of".
Construction is objective in the sense that it is concerned with what a reasonable person to whom the utterance was addressed would have understood the author to be using the words to mean.
The meaning of words is a matter of convention, governed by rules, which can be found in dictionaries and grammars.
However, on November 13, 2018 the USPTO switched to the claim construction standard established by the Court of Appeals for the Federal Circuit in Phillips v. AWH Corp., 415 F.3d 1303 (Fed.