Scope of Patent Protection under Intellectual Property
Scope of Patent Protection
What is the Scope of Patent Protection?
Patent protection grants the patent holder exclusive rights to make, use, sell, or license an invention for a limited time. The scope defines what exactly is protected, i.e., the boundaries of the patent monopoly.
Key Components Defining Scope
Claims of the Patent
Doctrine of Equivalents
Limitations on Scope (e.g., prior art, public use)
1. Claims Define the Scope
In patent law, the claims of the patent document are the legal boundaries of protection. The invention’s scope is limited to what is claimed.
In Markman v. Westview Instruments, Inc. (1996), the U.S. Supreme Court held that claim construction is a matter of law to be decided by the court.
📌 The language of claims determines the precise scope of what is protected.
2. Doctrine of Equivalents
Even if an accused product or process does not literally infringe the patent claims, it may still infringe if it performs substantially the same function in substantially the same way to achieve the same result.
In Graver Tank & Manufacturing Co. v. Linde Air Products Co. (1950), the Supreme Court established this doctrine.
📌 Protection extends beyond literal claim language to equivalent elements that avoid technical avoidance.
3. Limitations on Scope
The scope cannot cover what was already known (prior art) or obvious.
In KSR International Co. v. Teleflex Inc. (2007), the Court emphasized that patents should not cover obvious inventions.
📌 Patent scope is limited to novel and non-obvious inventions.
4. Prosecution History Estoppel
If a patentee narrows claims during prosecution to avoid prior art, they may be prevented from later claiming equivalents for the surrendered territory.
In Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (2002), the Court ruled that claim amendments can limit the doctrine of equivalents.
📌 Patent scope can be narrowed by prosecution history.
5. Public Use and On-Sale Bar (Limiting Scope)
In Pfaff v. Wells Electronics, Inc. (1998), the Court held that public use or sale of the invention before patent filing can bar patent protection, limiting the enforceable scope.
Summary Table of Scope of Patent Protection Principles
| Principle | Case Example | Explanation |
|---|---|---|
| Claims define legal scope | Markman v. Westview Instruments | Courts interpret claim language to determine boundaries |
| Doctrine of equivalents | Graver Tank v. Linde Air Products | Protects equivalent infringing products/processes |
| Novelty and non-obviousness | KSR Int’l v. Teleflex | Scope excludes known or obvious inventions |
| Prosecution history estoppel | Festo Corp. v. Shoketsu Kinzoku | Narrowing claims during prosecution limits equivalents |
| Public use/on-sale bar | Pfaff v. Wells Electronics | Pre-filing use or sale limits enforceable patent scope |
Practical Implications
Patent holders enjoy exclusive rights within the claim boundaries and equivalents.
Third parties must carefully analyze claims and prosecution history to avoid infringement.
Patent scope is not unlimited — prior art and public use restrict protection.
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