Claim (patent)

Claim (patent)

Patent claims are the part of a patent or patent application that defines the scope of protection granted by the patent. The claims define, in technical terms, the extent of the protection conferred by a patent, or the protection sought in a patent application. The claims are of the utmost importance both during prosecution and litigation.

For instance, a claim could read:

• "An apparatus for catching mice, said apparatus comprising a base for placement on a surface, a spring member..."
• "A chemical composition for cleaning windows, said composition comprising 10–15% ammonia, ..."
• "Method for computing future life expectancies, said method comprising gathering data including X, Y, Z, ..."

A patent is a right to exclude others from making, using, selling or offering for sale the subject matter defined by the claims. In order to exclude someone from using a patented invention in a court, the patent owner, or patentee, needs to demonstrate that what the other person is using falls within the scope of a claim of the patent. Therefore, it is more valuable to obtain claims that include the minimal set of limitations that differentiate an invention over what came before, i.e. the so-called prior art. On the other hand, the fewer the limitations in a claim, the more likely it is that the claim will cover or "read on" what came before and be rejected during examination or found to be invalid at a later time for lack of novelty.