Print PDF

Prosecution History Limits Keypad Recognition Claims to One-Syllable Elements

07-1388
July 24, 2008

Decision icon Decision

Last Month at the Federal Circuit - August 2008

Judges: Dyk, Prost (author), Hochberg (District Judge sitting by designation)

[Appealed from: W.D. Tex., Judge Sparks]

In Board of Regents of the University of Texas System v. BENQ America Corp., No. 07-1388 (Fed. Cir. July 24, 2008), the Federal Circuit affirmed a grant of SJ of noninfringement of a patent directed to the entry and transmission of words using a touch-tone telephone keypad.

The Court found that the district court properly construed the claims to require that the “vocabulary” relied on by the invention include only “syllabic elements,” and that the parties stipulated that none of the accused devices relies on a vocabulary of only syllabic elements. In so holding, the Court found that the claims had been narrowed during prosecution to cover a vocabulary of only syllabic elements, and thus were not infringed by the accused devices, which recognize broader elements.

The Board of Regents of the University of Texas System (“Board of Regents”) owns U.S. Patent No. 4,674,112 (“the ’112 patent”), entitled “Character Pattern Recognition and Communications Apparatus,” which is directed to an apparatus and method for “non-verbal entry” and transmission of a word (or words) using a standard, touch-tone telephone. For example, to enter the word “HELP” on the keypad, a user depresses a sequence of four keys (“4357”), one key for each letter of the word. While this four-key sequence corresponds to 81 different alphabetic character strings, only one of these strings corresponds to an English word— the word “HELP.” Thus, in order to resolve the ambiguity and correctly identify the inputted word, the method compares this sequence against a “vocabulary” of possible entries.

During the prosecution of the ’112 patent, the Board of Regents originally set forth in claim 10 a method of “matching said binary code with a pre-programmed code, said pre-programmed code being representative of an alphabetic character string.” However, the PTO rejected this claim as anticipated by a 1976 article (“Rabiner”) that describes processing a received signal “to identify the word or words of [a] request.” In response, the Board of Regents amended claim 10 by replacing “an alphabetic character string” with “a syllabic element” and cancelled a dependent claim that required matching with words.

The Board of Regents subsequently sued multiple defendants, including BENQ America Corp., Motorola Inc., and Kyocera Wireless Corp., for patent infringement. During claim construction, the Board of Regents argued that the term “syllabic element” should be broadly defined to include letter groups having any number of syllables. The district court disagreed and construed the term to mean “[a] one-syllable letter group that either comprises a word or can be combined with other one-syllable letter groups to form a word. A syllabic element may be as small as a single letter.” Slip op. at 8. The district court also construed the phrase “each pre-programmed code being representative of a syllabic element” to require that the vocabulary include only syllabic elements.

Shortly after the claim construction ruling, Motorola filed a motion for SJ of noninfringement in which it argued that its accused devices do not infringe the matching limitation of claim 10—i.e., “matching said binary code with one or more pre-programmed codes, each pre-programmed code being representative of a syllabic element.” The district court agreed after concluding that the plain language of claim 10 and the prosecution history require that each time a binary code is matched, it must be matched against a syllabic element. Moreover, the district court reasoned that if it were to adopt the Board of Regents’s argument that the accused devices “intermittently infringe” when they do match against a syllabic element, the prior art would anticipate the patent. Ultimately, the district court concluded that the accused devices do not infringe the matching limitation because none of the accused devices relies upon a vocabulary of only syllabic elements, even if certain entries in those vocabularies happen to be one syllable long. Based upon the claim construction and the grant of SJ to Motorola, the parties stipulated to judgment of noninfringement with regard to the remaining defendants and the district court entered final judgment.

On appeal, the Board of Regents challenged both the claim construction of “syllabic element” and the district court’s grant of SJ. First, the Board of Regents argued that the construction of “syllabic element” incorrectly requires a syllabic element to be one syllable. The Federal Circuit disagreed because it found that the ’112 patent specification repeatedly distinguishes between a “word” and a “syllabic element,” and confirms that the terms are not coextensive in scope. Further, the Court noted that the specification’s only example explains that the syllabic element “CON” is a one-syllable letter group that is both a word and able to be combined to form other words. In comparing this single-syllable letter group to multisyllabic words such as “contest, silicon, conference, contact, etc.,” the Court found that the specification implies that a syllabic element is limited to a single syllable.

The Federal Circuit also found that the Board of Regents’s broad reading of claim 10 “does not square with the prosecution history.” Id. at 13. Specifically, the Court found that the cancellation of the dependent claim indicated that the set of “syllabic elements” does not include all words. Moreover, the Court concluded that if “syllabic elements” included words, then Rabiner’s disclosure of matching words would teach the portion of claim 10 that was amended to distinguish Rabiner during prosecution. The Court, therefore, concluded that the proper construction of “syllabic element” is a one-syllable letter group that either comprises a word or can be combined with other one-syllable letter groups to form a word.

The Federal Circuit then turned to the construction of the phrase “each pre-programmed code being representative of a syllabic element.” The Court found that the PTO’s rejection forced the Board of Regents to distinguish its invention, as employing a database of “syllabic elements” that was different from Rabiner’s database of complete words, by amending claim 10. Accordingly, the Court concluded that “each pre- programmed code being representative of a syllabic element” means that the vocabulary only includes syllabic elements.

The Court also rejected the Board of Regents’s argument that, because claim 10 uses the presumptively open transitional phrase “comprising,” the Court should find infringement anytime an accused device satisfies the matching limitation and, thus, the addition of unrecited steps (such as matching with a pre-programmed code that is not representative of a syllabic element) should not defeat infringement. While the Court acknowledged that, generally, the use of the transitional phrase “comprising” does not exclude additional, unrecited steps, the Court concluded that the presumption “does not reach into each of the [claimed] steps to render every word and phrase therein open-ended—especially where, as here, the patentee has narrowly defined the claim term it now seeks to have broadened.” Id. at 17 (alteration in original) (quoting Dippin’ Dots, Inc. v. Mosey, 476 F.3d 1337, 1343 (Fed. Cir. 2007)).

Given its constructions of the “syllabic element” and “each programmed code” limitations, the Federal Circuit affirmed the grant of SJ of noninfringement.