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Claim differentiation

Definition

A canon of claim constructionclaim constructionThe legal process of interpreting what a patent claim means — usually decided by the judge in a Markman hearing.Read more →: different claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → are presumed to have different scope, so a limitation spelled out in a dependent claimdependent claimA claim that adds a limitation to another claim. Narrower in scope but easier to enforce.Read more → is presumed to be absent from the broader independent claimindependent claimA claim that stands alone — doesn't reference other claims. Defines the broadest scope of the invention.Read more → it depends on. It is used to argue an independent claim should be read broadly.

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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.

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Claim construction

The legal process of interpreting what a patent claim means — specifically, the scope of each term in the claim. In litigation, judges perform claim construction in a "Markman hearing" before deciding infringement. Claim construction is often the most consequential step in patent litigation: a narrow construction can defeat infringement, while a broad one can invalidate the claim.

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Dependent claim

A claim that refers back to and further limits another claim. For example: "The device of claim 1, wherein the housing is made of aluminum." If the claim it depends on is invalid, the dependent claim also falls. Dependent claims provide narrower protection but serve as fallbacks — if broader independent claims are invalidated, narrower dependent claims may survive.

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Independent claim

A claim that stands on its own and does not reference any other claim. An independent claim defines the broadest scope of protection for a particular aspect of an invention. Most patents have one to three independent claims, each capturing the invention from a different angle, with multiple dependent claims narrowing each one.

Conception

The mental part of invention: forming a definite and permanent idea of the complete invention in enough detail that a skilled person could build it. Conception, paired with reduction to practice, determines who legally counts as an inventor.

Claim chart

A side-by-side comparison table mapping each element of a patent claim to a specific feature in an accused product or prior art reference. Claim charts are used in infringement analysis, licensing negotiations, and patent litigation. They make it visually clear which claim elements are met (or not met) by the thing being compared.

See claim differentiation in real patents:

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