The doctrine of prosecution history estoppel is an important limitation in patent law that prevents patent holders from reclaiming claim scope that they surrendered during the patent prosecution process to obtain approval. Prosecution history estoppel can potentially affect secondary infringement analysis by defining the scope of claims which may be enforced by complainers against defendants. Secondary infringement, such as induced and contributory infringement, encompasses indirectly enable or encourage the infringement of a patent. In these situations, this article discusses the consequence of prosecution history estoppel in secondary infringement analysis.

What is Prosecution History Estoppel?

Prosecution history estoppel is a legal principle in patent law that stops a patent holder from claiming rights that are broader than what they accepted during the patent's prosecution. In simple terms, when a patent applicant makes concessions like narrowing their claims to address rejections from the patent office they may be not allowed for further claiming of the patent.

What is secondary Infringement analysis?

Infringement includes primary and secondary infringement, primary infringement is direct infringement and secondary infringement is an indirect infringement. Secondary infringement must involve knowledge from the infringer relevant to the copyrighted work. Usually, the secondary infringers could be the retailers or publishers.

A secondary infringement occurs when a party is accused of contributing to or inducing direct infringement by another party. The two main types of secondary infringement are:

1. Induced Infringement: Induced infringement happens when a party encourages or directs another to infringe a patent.
2. Contributory Infringement: Contributory infringement happens when a party sells or supplies a component to another party.

Doctrine of prosecution history Impact on Induced Infringement

The concept of prosecution history estoppel is one that is commonly used as a means of defense for someone who is considered to be accused of inducing. For example, a patent holder might have responded to a rejection by narrowing the scope of his invention, say, by describing it as a specific device or feature in the course of prosecution, then the accused inducer can argue that the patent holder is barred from making broader infringement allegations based on the similar description the inducer has just given.

In this way, the prosecution history estoppel can contribute to restricting the scope of patent claims, and as a result, it can minimize the risk of indirect infringement claims.

Doctrine of prosecution history Impact on Contributory Infringement

In cases of contributory infringement, the accused party offers a product or part that has no major use except when combined with a patented invention. The doctrine of prosecution history estoppel can narrow the scope of a claim and, as a result, limit a finding of contributory infringement.

For example, a patent owner had to narrow down their claim to certain materials or designs during the examination stage. Later on, they can't narrow down their claims to include parts that aren't in the updated scope. The infringer might say that the component or materials they provide isn't covered by the narrowed claims. The prosecution history estoppel would stop the owner from expanding their claims to include those components.

Advantages

• Reduce the risk of infringement
• Encourage new innovations
• Reduce the burden in courts
• Save time

Conclusions

Prosecution history estoppel has a great influence on the patent claim and in secondary infringement analysis. The infringers who are accused can use prosecution history estoppel to argue against the patent holder's attempt to broaden the scope of the claims to include new products and/or technologies that were not disused during the prosecution phase. For those who involved in secondary infringement disputes whether as accused infringers or patent holders it is crucial to understand the potential impact of prosecution history estoppel and incorporate this awareness into litigation strategy.

About Effectual

Effectual Services is an award-winning Intellectual Property (IP) management advisory & consulting firm offering IP intelligence to Fortune 500 companies, law firms, research institutes and universities, and venture capital firms/PE firms, globally.

Through research & intelligence we help our clients in taking critical business decisions backed with credible data sources, which in turn helps them achieve their organisational goals, foster innovation and achieve milestones within timelines while optimising costs.

Related Resources

Did you know the key to accurate infringement analysis- Defining metes and bounds

The Role of Source Code in Proving Patent Infringement

Do You Know Effective Methods for Assessing Patent Infringement with Prior Art?

Patent Infringement & Case studies