The US Patent and Trademark Office (USPTO) this week issued a memorandum related to guidelines for examining patent claims with means-plus-function and step-plus-function limitations under 35 USC § 112(f). The memorandum primarily serves as a reinforcement and clarification of existing practices rather than introducing new legal standards regarding 35 USC § 112(f).
The memorandum, dated March 18, 2024, does not present new changes but reminds examiners of the resources available for examining claims under 35 USC § 112(f). It serves as a refresher on current guidelines and practices.
Detailed interpretation guidance: While the principles around means-plus-function and step-plus-function claim limitations are not new, the memorandum reiterated how to interpret these claims using the three-prong analysis under § 112(f).
Clarification on presumptions and interpretations: The memorandum clarifies existing presumptions about the use of terms like “means” or “step” in claims and the conditions under which these presumptions can be overcome. This clarification helps ensure consistency in how patent examiners approach claim interpretation.
Applicability of § 112(f): It allows claim drafters to describe an element in a claim as a means or step for performing a specified function without explicitly stating the supporting structure, material, or acts. This is significant for both clarity and the scope of patent claims.
Three-prong analysis for claim interpretation: Examiners are instructed to use a three-prong test to determine if a claim limitation invokes § 112(f):
Presumptions and interpretations: The memo clarifies presumptions around the use of “means,” “step,” or a generic placeholder and their implications, emphasizing the need for careful examination and recordation based on claim language and the common understanding in the relevant technological field.
Evaluation of supporting disclosure: For a § 112(f) limitation, the adequacy of supporting disclosure must be evaluated under §§ 112(a) and (b). This includes assessment for definiteness, written description, and enablement.
Focus on supporting disclosure requirements: Emphasizing the importance of adequate supporting disclosure in the patent specification, the memorandum underscores the necessity of clear linkage between the claim’s functional language and the structure, material, or acts disclosed in the specification.
Specific considerations for computer-implemented claims: The memorandum reiterates the requirement for computer-implemented claims under § 112(f) to disclose a specific algorithm for the claimed function, ensuring these claims meet the definiteness requirement. The algorithm may be expressed in any understandable terms including as a mathematical formula, in prose, in a flowchart or other manner that provides sufficient structure.
Reinforcement of examiner responsibilities: The memo reinforces the examiner's role in making the record clear regarding their interpretation of § 112(f) limitations, which is crucial for patent prosecution and any subsequent legal challenges.
If you have any questions or would like more information on the issues discussed in this LawFlash, please contact any of the following: