The written description requirement, as stated in 35 U.S.C. § 112, mandates that a patent’s specification must “contain a written description of the invention.” The standard determines whether the disclosure reasonably conveys to those skilled in the art that the inventor had possession of the claimed invention. A substantial body of case law provides guidance on how to meet this requirement. The Federal Circuit’s decision in Hologic, Inc. v. Smith & Nephew, Inc. (Fed. Cir. March 14, 2018) offers another useful example of how to evaluate compliance with the written description requirement. Specifically, the court relied on both the text and drawings in the patent specification to establish that the written description requirement was satisfied. The court further reasoned that the structural assembly of the device supported the claimed limitations.
Case Summary: Hologic, Inc. v. Smith & Nephew, Inc.
In this case, Smith & Nephew (S&N), the patent owner, alleged that Hologic infringed its patent, U.S. Patent No. 8,061,359 (‘359 patent). In response, Hologic initiated an inter partes reexamination in an effort to invalidate the patent and avoid infringement liability. This appeal arises from the inter partes reexamination decision.
The ‘359 patent originated from a national stage U.S. application based on an earlier-filed PCT application. Notably, the PCT application was made public more than one year before the filing date of the U.S. application that matured into the ‘359 patent. Hologic argued that the claims in the ‘359 patent lacked written description support in the earlier-filed PCT application, making it prior art and rendering the ‘359 patent invalid.
Key Claim Terms and Written Description Analysis
Hologic contested three key claim terms, arguing they lacked written description support in the earlier PCT application: “light guide,” “first channel,” and “permanently affixed.”
1. Written Description for “Light Guide”
The ‘359 patent claims recited a “light guide,” a term absent in the earlier-filed PCT application. Hologic argued this absence meant the PCT application did not provide sufficient written description. However, the Federal Circuit disagreed, finding that the PCT application’s disclosure of a “fiber optic bundle” inherently described a type of light guide. The court reasoned that disclosing a specific species (fiber optic bundle) can provide written description support for the broader genus (light guide).
Key Takeaways:
- Avoid narrowing the written description to specific species to preserve broad patent protection.
- In foreign jurisdictions, written descriptions typically require explicit mention of both the genus and species, as well as any intermediate generalizations.
2. Written Description for “First Channel”
The Federal Circuit found written description support for “first channel” in Figures 2 and 3 of the drawings, where element 6 was described as a “light channel” or “viewing channel.” U.S. patent laws allow written description support to be derived from the specification’s drawings and text, even if exact claim terms are not used. Additionally, the claims of the earlier-filed PCT application themselves provided written description support for this term.
Key Takeaway:
- While U.S. patent laws permit broader interpretations, many foreign jurisdictions demand closer alignment between claim terms and the specification.
3. Written Description for “Permanently Affixed”
For the term “permanently affixed,” the Federal Circuit found support in the drawings, the textual description, and the device’s structural assembly. The court highlighted that the assembly’s design, where a viewing channel was “bookended” by specific components, evidenced that the parts formed a unitary, non-removable structure.
Practical Advice for Patent Prosecutors
Patent prosecutors should strive to anticipate potential litigation issues during prosecution. Although the USPTO applies a liberal standard for the written description requirement, foreign jurisdictions often require stricter compliance. To mitigate risks of invalidation due to insufficient written description:
- Explicitly describe features implied by drawings or the device’s context.
- Include descriptions of species, genus, and intermediate generalizations where relevant.
- Aim for a conservative approach, providing as much detail as possible within time and resource constraints.
While perfect foresight is unattainable, these strategies can help strengthen a patent’s enforceability and reduce litigation risks.
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