Patent claim
Also called claim, patent claims, independent claim, dependent claim, claim set
Patent claim is one of the numbered sentences at the end of a patent or patent application that define the matter for which protection is sought1,2. In the US, the specification must conclude with one or more claims particularly pointing out and distinctly claiming the subject matter the inventor regards as the invention3.
A claim may be written in independent form or, where the case allows, in dependent or multiple dependent form. A dependent claim refers to an earlier claim, adds a further limitation and incorporates all the limitations of the claim it refers to3.
Independent and dependent claims
| Type | What it does | Rule |
|---|---|---|
| Independent | Does not refer back to another claim. Under the EPC, a claim stating the essential features may be followed by claims to particular embodiments4 | 35 U.S.C. 112(c); Rule 43(3) EPC3,4 |
| Dependent | Refers to a claim previously set forth, specifies a further limitation, and incorporates all the limitations of that claim3 | 35 U.S.C. 112(d); Rule 43(4) EPC3,4 |
| Multiple dependent | In the US, refers in the alternative only to more than one earlier claim, and cannot serve as the basis for another multiple dependent claim3 | 35 U.S.C. 112(e)3 |
The USPTO's test for a proper dependent claim is that it includes every limitation of the claim it depends from and adds a further one. The MPEP's own illustration: if claim 1 recites elements A, B, C and D, a claim that omits D or replaces it with E is not a proper dependent claim1.
A dependent claim is examined as a combination of everything in its base claim plus its own limitation, and that combination is compared with the prior art as if it were one independent claim1.
How a US claim is written
- Each claim is the object of a sentence starting with "I (or we) claim" or "The invention claimed is" (or an equivalent). It begins with a capital letter and ends with a period1.
- Several claims are numbered consecutively in Arabic numerals, and the least restrictive claim should be presented as claim 1 (37 CFR 1.75(f) and (g))1.
- Where a claim sets forth several elements or steps, each should be separated by a line indentation (37 CFR 1.75(i))1.
- Claim terms must find clear support or antecedent basis in the description, so their meaning can be ascertained from it (37 CFR 1.75(d)(1))1.
- More than one claim may be presented if they differ substantially and are not unduly multiplied (37 CFR 1.75(b))1.
For improvement inventions, 37 CFR 1.75(e) describes a form with a preamble of the known elements, a phrase such as "wherein the improvement comprises", and then the new or improved portion1. The European counterpart is the two-part form of Rule 43(1) EPC, whose characterizing portion begins "characterised in that" or "characterised by"4.
Clarity and support
In the US, a patent is invalid for indefiniteness if its claims, read in light of the specification and the prosecution history, fail to inform those skilled in the art about the scope of the invention with reasonable certainty5.
Under the EPC, the claims must be clear and concise and be supported by the description (Article 84 EPC)2. Except where absolutely necessary, claims must not rely on references to the description or drawings, such as "as illustrated in figure ..." (Rule 43(6) EPC)4.
Claim rules by jurisdiction
United States
- The specification must conclude with one or more claims particularly pointing out and distinctly claiming the invention (35 U.S.C. 112(b))3.
- The MPEP calls the claims the definition of that for which protection is granted1.
- Reference characters in a claim should be placed in parentheses, and their presence or absence generally does not affect the scope of the claim1.
Europe
- The claims define the matter for which protection is sought (Article 84 EPC)2.
- An application may contain more than one independent claim in the same category only for interrelated products, different uses of a product or apparatus, or alternative solutions to a particular problem where a single claim would be inappropriate (Rule 43(2) EPC)4.
- The extent of protection is determined by the claims, and the description and drawings are used to interpret them (Article 69(1) EPC)6.
China
- The claims must be based on the description and define the scope of protection sought clearly and concisely (Patent Law of the PRC, Article 26)7.
- For an invention or utility model patent, the scope of protection is confined to the content of the claims, and the description and drawings may be used to explain them (Article 64)7.
Claims vs description vs abstract
In a patent document, the claims determine the extent of protection (Article 69(1) EPC). The other parts play different roles6.
| Part | Its job | Effect on scope |
|---|---|---|
| Claims | Define the matter for which protection is sought2 | Determine the extent of protection (Article 69(1) EPC)6 |
| Description | Describes the invention and how to make and use it, in terms that enable a person skilled in the art to do so (35 U.S.C. 112(a))3 | Used to interpret the claims (Article 69(1) EPC6; in the US, claims are read in light of the specification5) |
| Abstract | Serves the purpose of technical information only (Article 85 EPC)8 | May not be taken into account for interpreting the scope of protection sought (Article 85 EPC)8 |
Seen in the record
The US Supreme Court set the current test for when claim language is too unclear to satisfy 35 U.S.C. 1125. The decision is cited for the legal standard; it says nothing about either party beyond the record.
Nautilus, Inc. v. Biosig Instruments, Inc.
The Court replaced the "insolubly ambiguous" standard and held that claims must inform those skilled in the art about the scope of the invention with reasonable certainty5.
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Start draftingQuestions people ask
What is the difference between an independent and a dependent claim?
An independent claim does not refer to another claim. A dependent claim refers to an earlier claim, adds a further limitation and incorporates all the limitations of that claim1,3.
How many claims can a patent application have?
There is no fixed maximum, but extra claims cost more. In the US, more than one claim may be presented if they differ substantially and are not unduly multiplied1, and excess-claims fees are due for each independent claim over 3 and each claim over 20 (35 U.S.C. 41(a)(2))9. Under the EPC, the number of claims must be reasonable (Rule 43(5) EPC)4, and a claims fee is payable for the sixteenth and each later claim (Rule 45(1) EPC)10.
Does the description limit what the claims cover?
The claims set the scope, but the description is used to read them. Under Article 69(1) EPC the description and drawings are used to interpret the claims6, and in the US claims are read in light of the specification and prosecution history5.
Why is claim 1 usually the broadest claim?
US rules say the least restrictive claim should be presented as claim 1, with dependent claims grouped with the claims they refer to1. The MPEP also suggests filing claims that range from the broadest the applicant believes it is entitled to down to the most detailed it will accept1.
How it connects
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