When does omitting a limitation violate the written description requirement?

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Source: FAQ (MPEP-Based) BlueIron Update: 2024-09-30 10 Rules 5 Related FAQs This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice. Omitting a limitation can violate the written description requirement when the omitted element is described as essential or critical to the invention in the original disclosure. The MPEP 2163.05 states: “A claim that omits an element which applicant describes as an essential or critical feature of the invention originally disclosed does not comply with the written description requirement.” This principle is illustrated in case law, such as Gentry Gallery, Inc. v. Berkline Corp. , where claims were invalidated for removing the location of a control means that was described as the “only possible location” in the original disclosure. Related Rules from the Manual of Patent Examining Procedure 10 rules Collapse Written Description Requirement Ensures Claims Match Specification MPEP 2163 Written Description Requirement for Genus Species MPEP 2163 Written Description Requirement Can Be Met with Function and Minimal Structure MPEP 2163 Permitted Claim Must Describe Critical Feature MPEP 2163.05 Claim Must Describe Critical Feature MPEP 2163 Written Description Requirement for Genus Claims MPEP 2163.05 Permitted Written Description Requirement for Genus-Species MPEP 2163 Written Description Requirement for Genus Species MPEP 2163 Written Description Requirement Must Be Satisfied By Broad Disclosure MPEP 2163 Written Description Requirement Not Necessarily Detailed MPEP 2163 Required Other Related FAQs 5 FAQs Collapse How does adding a specific limitation to a claim affect its scope? How does changing numeric range limits affect patent claim scope? How can a genus claim satisfy the written description requirement? What is the significance of the genus-species relationship in patent claims? What is th...