Less Common Defenses To Patent Infringement

• Jurisdiction: United States,Federal
• Law Firm: Wolf, Greenfield & Sacks, P.C.
• Subject Matter: Intellectual Property, Patent
• Author: Mr Jason Balich
• Published date: 25 September 2023

Technology companies and manufacturers know that they do not infringe a patent if they (or their products) do not practice a claimed invention. But did you know that there are certain circumstances where your company or its products can practice every single element of a patent and not legally infringe that patent?

The doctrines of intervening rights and prior commercial use allow for just that. For the accused infringer, these principles are the equivalent of a get-out-of-jail-free card. For the patent owner looking to assert its patents, they can be a death knell.

Intervening rights

Intervening rights stem from the inequities of a person obtaining a patent ' and thus putting the public on notice as to a claimed invention ' and then later changing the scope of the claimed invention through a reissue application.

Whether the scope of the reissue patent is broader than the original patent, or narrower to avoid prior art, so long as the scope of the claims of the reissue patent is materially different than the scope of the claims of the original patent, intervening rights may be a total defense to infringement of the reissue patent.

There are two types of intervening rights: (1) absolute intervening rights and (2) equitable intervening rights. Both are codified in 35 U.S.C.A. ' 252, ' 2.

Absolute intervening rights

Absolute intervening rights allow a person to keep using or selling things that were already in existence at the time the reissue patent issues when the reissue patent has claims that are of a materially different scope than the claims in the original patent.

For example, if you were using a process covered by a reissue patent having materially different claims from the original claims, you could keep using that process even after the reissue patent issues. If you had inventory of a product that infringed the scope of the reissue patent, you could sell off that inventory and not infringe the reissue patent.

Absolute intervening rights do not, however, provide a defense to infringement where the process or product at issue infringed one or more claims of the original patent and the original patent has claims with substantially the same scope. Meaning that if the process or product infringed the original patent and claims of the same scope are in the reissue patent, intervening rights do not apply.

Also, absolute intervening rights do not allow a person to make and sell more of the type of things that were already in existence. For example, while absolute intervening rights may allow you to sell down already existing inventory of an infringing good, they do not allow you to make more of that product after the reissue patent issues. Similarly, even if you offered to sell a product prior to the reissue patent, you cannot then make and actually sell it after the reissue patent issues.

Equitable intervening rights

The second type of intervening rights ' equitable intervening rights ' may allow a person to continue infringing a reissue patent if a judge sitting in equity is convinced that you, the accused infringer, made "substantial preparation" for that infringement and only "for the protection of investments made or business commenced."¹

The Federal Circuit has established a six-factor...