Regents of the University of Minnesota v. LSI Corporation

Background

The Regents of the University of Minnesota (UMN) sued LSI Corporation and Avago Technologies U.S. Inc. for infringement of U.S. Patent No. 5,859,601, concerning methods and apparatus for implementing maximum transition run codes. UMN asserted claims 14 and 17. Both claims depend on claim 13, and the disputed terms came from claim 13.

The patent concerns digital storage systems that record data as ones and zeroes. It describes maximum transition run codes, which limit the number of consecutive transitions and non-transitions in an encoded waveform. The patent can use block codes or state-dependent codes. The Patent Trial and Appeal Board previously held claim 13 unpatentable but did not invalidate claims 14 and 17; the Federal Circuit affirmed that decision. This order addressed the meaning of disputed claim terms and did not decide infringement.

Legal Standard

Claim construction is the court’s interpretation of patent claims. The court begins with the claim language and considers the patent’s specification, prosecution history, and, when useful, outside evidence such as expert testimony and dictionaries. The court gives claim terms their ordinary meaning to a person skilled in the relevant field, viewed in the context of the entire patent.

Producing sequences of n-bit codewords

The court rejected LSI’s argument that the term excludes state-dependent codes. LSI relied partly on statements made by UMN’s attorney during Federal Circuit oral argument, but the court found those statements were not a clear and unmistakable disclaimer. The court also found that the patent’s language and specification contemplate state-dependent codes.

The court agreed with LSI that the codewords must be understood as combined into a sequence so that the patent’s constraints apply across codeword boundaries, not merely to each codeword separately. The court declined to use the more technical word “concatenated.” Its construction was:

“producing, as output from the received binary datawords, n-bit codewords that are combined into a sequence.”

Encoded waveform

The court adopted UMN’s proposed construction: “the recorded waveform.” Although the claim uses both “recorded waveform” and “encoded waveform,” the court found that the different wording did not require different meanings here. The claim’s use of “the” supplied an earlier reference to the recorded waveform, and the claim language and prosecution history treated the two terms interchangeably.

Transition

The parties disputed whether the Patent Trial and Appeal Board’s earlier construction of “transition” prevented the district court from adopting UMN’s proposed meaning. The court held that the earlier decision could have a preclusive effect because the Board applied the same claim-construction standard, addressed the same term, issued a final decision, and considered the same parties.

The court concluded that the Board had expressly decided the meaning of “transition,” so UMN could not relitigate that issue. The court therefore adopted LSI’s construction, with one modification: it used “recording format” instead of “encoding format” when referring to the non-return-to-zero and non-return-to-zero-inversion formats. The construction was:

“plain and ordinary meaning; a transition can be logically represented in multiple ways depending on the recording format used—a change from 0 to 1 or from 1 to 0 when using NRZ format, for example, or a 1 when using NRZI format.”

Disposition

Judge Edward J. Davila entered the claim-construction order and stated that the disputed terms were construed as set out in the order. The body of the opinion addresses three terms: “producing sequences of n-bit codewords,” “encoded waveform,” and “transition.” The reproduced final table visibly lists the first and third terms but does not separately display “encoded waveform,” even though the opinion expressly adopts “the recorded waveform” as that term’s construction.