In patent law, a claim defines the scope of protection offered by a patent. Specifically, claims set forth the boundaries of what is protected by the patent, allowing other parties to determine when a product or process might infringe on another party’s patent. As a result, drafting claims represents one of the most critical parts of developing a patent application, as claims can determine the strength of a patent’s protection.
When looking at a U.S. patent, the claims are at the very end, after the cover page, drawings, and specification, and they are presented as a numbered list.
Patents confer a negative right, so the claims of a patent tell the public what they cannot do without infringing upon the patent. Patent claims differ from the patent specification, which provides a detailed description of the invention, upon which the claims define the scope of legal protection provided by the patent. If a feature is described within the specification, it does not automatically follow that it is covered by the patent. That feature must be in the claims of the patent to be protected and enforceable against another party. However, that feature’s presence in the specification may serve as prior art to others or as basis for future claims.
The Structure of a Claim in Patent Law
In a patent, a claim is a sentence that describes what is covered by the patent. While a claim is a single sentence, it doesn’t often look or read like a traditional sentence. A claim can include, for example, a series of limitations separated by commas or semicolons, multi-level lists, and clauses starting with phrases like “wherein.” It is not unheard of for a single claim to be pages long!
In general, patent claims follow a basic format. First, a claim will have a “preamble” that introduces the fundamental nature of the invention (e.g., a product or method). The claim may then use a transitional phrase like “comprising,” “consisting essentially of,” or “consisting of” that describes the scope of the claim. Each of these transitional phrases has a specific meaning under patent law.
The term “comprising” is an open-ended transitional phrase, meaning that the claim elements must be present for infringement to occur, but the claim does not exclude additional, unrecited elements or method steps. For example, if a claim is directed to an article comprising elements A, B, and C, a product having elements A, B, C, and D could still infringe on the claim because it has all of the required elements (A, B, and C).
“Consisting of” excludes any element, step, or ingredient not specified in the claim. If a claim is directed to a composition consisting of elements E, F, and G, a composition having elements E, F, G, and H may not be infringing on the claim due to the presence of additional elements (element H).
The transitional phrase “consisting essentially of” can sometimes be a middle ground between “comprising” and “consisting of,” limiting the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention.
Finally, the body of the claim details the elements or steps of the innovation to be covered by the patent.
Types and Categories of Patent Claims
Patent claims are classified as either independent or dependent. An independent claim refers to a standalone claim that can define the scope of an invention protected by a patent without relying on any other claim. Conversely, a dependent claim relies upon and add limitations to an independent claim or another dependent claim. Applicants can use dependent claims to cover various embodiments and to provide additional protection by anticipating refinements or workarounds for the independent claim.
Certain jurisdictions permit claims in “multiple dependent” form, where a dependent claim can depend from multiple claims (using phrasing like “The article of any of the preceding claims”); however, this is generally not a permitted format in the U.S. (instead, permitted phrases include “The article of claim 1”).
Patent claims can fall generally into the categories of product claims or method claims. Product claims may be either active (for example, describing an apparatus, device, or machine) or non-active (for example, describing a composition of matter or article of manufacture), or a combination of both. A method claim, on the other hand, addresses the steps of a process or a series of acts performing a desired function. Method claims can cover manufacturing, assembling, or using the invention described by the patent.
A patent can, and should, have numerous claims. The United States Patent and Trademark Office (USPTO) allows for 20 total claims, with up to three independent claims. There is a fee for additional claims.
Why Claims Matter
Patent claims matter by setting the enforceable boundaries of the patent. Having a well-defined claim can deter other parties from infringing upon a patent or give a patent owner a better chance of enforcing their patent. Conversely, weak or ambiguous claims can lead to rejection of the patent application or invalidation of the patent. If a claim is very narrow, this may also allow parties to develop workarounds to avoid infringing on the patent.
Applicants should pay close attention to the words they choose to use in a patent claim. Using precise language strategically can help avoid unnecessarily narrow claims that offer reduced legal protection or overly broad claims that can lead to a lack of clarity or invalidation of a patent.
Note that only the claims of a granted patent are enforceable. While pending claims of a patent application may give an indication of the desired coverage by a patent applicant, it does not necessarily mean the applicant will be granted a patent with claims of that same scope. Often, during prosecution of a patent application (the negotiations between the applicant and the patent examiner), the scope of a claim will change based on prior art, examiner feedback, a change in strategy, or for other reasons.
Working with a Patent Attorney to Develop Claims
Inventors or applicants with limited or no experience drafting patent claims can still create strong, enforceable claims by working with a skilled patent attorney. A patent attorney brings both legal knowledge and technical understanding to prepare claims with an appropriate and defensible scope. They can evaluate relevant prior art in an effort to present claims with subject matter that is both novel and non-obvious. Patent attorneys also have experience interacting with the USPTO and can adjust claim language during prosecution to address examiner feedback. This informed professional guidance helps applicants secure broader and more enforceable protection for their innovations.