How are open-ended numerical ranges evaluated in patent claims?

Open-ended numerical ranges in patent claims require careful analysis for definiteness. The MPEP provides guidance on how these ranges are evaluated:

• Ambiguities can arise when an independent claim recites an open-ended range and a dependent claim sets forth specific amounts that appear to exclude the open-ended component.
• Claims that include theoretical content greater than 100% are not necessarily indefinite if they cannot exist in fact.
• Maximum limits without specified minimums may be acceptable in certain contexts.

As stated in MPEP 2173.05(c): “Open-ended numerical ranges should be carefully analyzed for definiteness.” The MPEP also notes: “It was observed that subject matter which cannot exist in fact can neither anticipate nor infringe a claim.” (In re Kroekel, 504 F.2d 1143, 183 USPQ 610 (CCPA 1974))

Additionally, the MPEP clarifies certain terms: “the term ‘up to’ includes zero as a lower limit, In re Mochel, 470 F.2d 638, 176 USPQ 194 (CCPA 1974); and ‘a moisture content of not more than 70% by weight’ reads on dry material, Ex parte Khusid, 174 USPQ 59 (Bd. App. 1971).”

To learn more:

• open-ended ranges
• patent claims
• definiteness
• maximum limits
• theoretical content