The Patent Trial and Appeal Board (PTAB) has denied a petition for inter partes review of Phenix Longhorn LLC’s patent, ruling that the petitioner failed to properly address means-plus-function claim limitations as required by USPTO rules.
Background
In IPR2025-00044, Petitioner challenged claims 1-3, 5, and 6 of U.S. Patent No. 7,557,788 B1, titled “Gamma Reference Voltage Generator.” The patent relates to a programmable buffer integrated circuit for generating gamma correction reference voltages used in liquid crystal displays (LCDs).
Key Issue: Means-Plus-Function Claim Construction
The central issue in the case involved proper construction of “means for executing” limitations found in the challenged claims. Under 37 C.F.R. § 42.104(b)(3), petitions must identify the specific portions of the specification that describe the structure corresponding to means-plus-function claim elements. The PTAB found that Petitioner failed to satisfy the mandatory claim construction requirements in multiple ways:
First, the Petitioner took contradictory positions on whether certain claim limitations were means-plus-function terms. As the Board noted: “Petitioner’s argument that claim 3’s ‘means for executing . . . ‘ is means-plus-function language (Pet. 12–14) conflicts and is at odds with Petitioner’s argument that claims 1 and 5’s ‘means for executing’ (discussed above) is not means-plus-function language (Pet. Reply 5).”
Second, the Board emphasized that when claims contain means-plus-function limitations, petitioners must “identify the specific portions of the specification that describe the structure, material, or acts corresponding to each claimed function.” Petitioner failed to do this for any of the challenged claims. The use of the term “means” creates a rebuttable presumption that 35 U.S.C. § 112 ¶ 6 applies. The Board found that “the Petition does not address the presumption and, more specifically, the Petition does not provide any argument or evidence as to why the presumption is rebutted.”
The Rule 42.104(b)(3) Violation
The Board’s decision heavily relied on the USPTO’s Consolidated Trial Practice Guide, which states: “Where claim language may be construed according to 35 U.S.C. § 112(f), a petitioner must provide a construction that includes both the claimed function and the specific portions of the specification that describe the structure, material, or acts corresponding to each claimed function. 37 C.F.R. § 42.104(b)(3).” The Guide further warns: “A petitioner who chooses not to address construction under § 112(f) risks failing to satisfy the requirement of 37 C.F.R. § 42.104(b)(3).”
Petitioner’s Failed Arguments
Petitioner attempted several arguments to avoid the rule requirements:
- District Court Reliance: Petitioner argued that neither party had identified these terms as means-plus-function in parallel district court litigation. The Board rejected this, noting it was Petitioner’s burden to comply with IPR rules regardless of district court proceedings.
- Alternative Construction: Petitioner proposed an alternative construction referring to a “programming interface which executes an optimization algorithm,” but failed to identify where this structure was described in the specification.
- Indefiniteness Arguments: Petitioner argued the claims were indefinite, but the Board noted that “indefiniteness is not one of [the grounds that can be raised in IPR under §§ 102 and 103].”
Impact on Obviousness Analysis
The claim construction failures had cascading effects on the obviousness analysis. The Board explained: “Because Petitioner has not identified structure corresponding to the functions recited in claims 1, 3, and 5, or explained how that structure is taught by the prior art, Petitioner has not presented us with evidence sufficient to ascertain the differences between the claimed invention and the asserted prior art.”
The Board concluded: “Because the Petition fails to rebut the presumption that claim 1 and 5’s ‘means for executing a predetermined algorithm according to a predetermined criteria and data sensed by said at least one sensor’ is a means-plus-function term and fails to identify corresponding structure in the Specification… the Petition does not comply with our rules.”
Key Takeaways
- Mandatory Compliance: Rule 42.104(b)(3) requirements are not optional—petitioners must address means-plus-function limitations properly or risk denial.
- Consistency Required: Petitioners should avoid taking contradictory positions on whether claim terms are means-plus-function limitations.
- District Court Irrelevant: Positions taken or not taken in parallel district court litigation do not excuse compliance with IPR procedural rules.
- Structure Identification Essential: For computer-implemented means-plus-function terms, petitioners must identify specific algorithms, not just general hardware like “programming interfaces.”
This decision serves as a stark reminder that procedural compliance in IPR petitions is not merely technical, it’s essential for institution.
The case was decided before Administrative Patent Judges Kevin F. Turner, Michael J. Strauss, and David C. McKone, with Judge Strauss writing for the Board. The decision is Innolux Corporation v. Phenix Longhorn LLC, Case No. IPR2025-00044, Paper 11 (Decision Denying Institution of Inter Partes Review) (PTAB June 9, 2025).
The authors of www.PatentLawyerBlog.com are patent trial lawyers at Jeffer Mangels Butler & Mitchell LLP. For more information about this case, contact Greg Cordrey at 949.623.7236 or GCordrey@jmbm.com.