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Construction of the Claim Term “Binary Code” That Would Encompass “Trinary Code” Was Internally Inconsistent and Contradicted the Specification

07-1314- 1467
February 19, 2008

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Last Month at the Federal Circuit - March 2008

Judges: Rader (author), Clevenger, Dyk

[Appealed from: N.D. Ill., Judge Moran]

In Chamberlain Group, Inc. v. Lear Corp., Nos. 07-1314, -1467 (Fed. Cir. Feb. 19, 2008), the Federal Circuit reversed the district court’s construction of the claim term “binary code,” vacated the preliminary injunction it had granted against Lear Corporation (“Lear”), and remanded.

The Chamberlain Group, Inc. (“Chamberlain”) owns U.S. Patent No. 6,154,544 (“the ’544 patent”). The ’544 patent is directed to an invention that improves security in remote-control garage door openers. The remote-control garage door opening systems claimed in the ’544 patent comprise a transmitter and a receiver. The transmitter and receiver communicate via an encrypted signal. In the claimed invention, part of the signal changes with each transmission (rolling or variable code). The rest of the signal remains fixed (fixed code). To further enhance signal encryption, the variable code is converted from a “binary code” to a “trinary code” before signal transmission. The receiver compares the transmitted fixed code and the variable code with stored codes to activate the door opener.

Chamberlain and Johnson Controls Interiors LLC, Chamberlain’s exclusive licensee, sued Lear, charging Lear with infringement of the ’544 patent. The district court construed “binary code” as “a code in which each code element may be either of two distinct kinds of values, which code may represent various kinds of letters and numbers including, but not limited to, a representation of a base 2 number,” and stated that “binary code” could not encompass a trinary code. Slip op. at 4. Then, on Chamberlain’s motion for a preliminary injunction, the district court noted that the parties agreed that computers necessarily operate in “binary code.” While Lear characterized its transmitter as using only trinary numbers, Lear conceded that this trinary number was still represented by 0s and 1s in a computer. The district court characterized Lear’s trinary number, as represented in a computer, as a “binary-coded trinary number,” and on this basis found that Lear’s transmitter would likely satisfy the “binary code” limitation, as claimed by the ’544 patent. Id. at 5. From there, the district court evaluated the remaining parts of the traditional four-factor test for injunctive relief and imposed a preliminary injunction on Lear. Lear appealed.

On appeal, the Federal Circuit reversed the district court’s construction of “binary code.” In so doing, the Court observed that the district court interpreted “binary code” to refer to the basic form for computer expression or storage of a given number, rather than its meaning. The Court noted that under the district court’s interpretation, “binary code” could refer to any numbering system expressed as 0s and 1s, including binary numbers and trinary numbers. The Court reasoned that while the district court’s construction may represent an ordinary reading of “binary code,” the ’544 patent restricted “binary code” to a narrower meaning.

In examining the meaning of “code” as used in the claims, the Court found that the term “trinary code” was relevant in construing “binary code” because the term “code” presumptively should carry the same meaning throughout the ’544 patent. The parties agreed that “binary” meant “base 2” and “trinary” meant “base 3,” or as claim 1 recited, “three-valued.” Thus, the Court noted that “binary code” and “trinary code” should have parallel meanings, differing only insofar as “binary” and “trinary” differ in their relationships to the numbers 2 and 3.

The Court observed that because the trinary code of the ’544 patent is stored in the transmitter’s microcontroller, and the transmitter’s microcontroller, like other computers, undisputedly stores and processes data as sequences of 0s and 1s, “trinary code” as used in the ’544 patent means values stored and processed in the binary language as 0s and 1s. The Court noted that the district court’s construction of “binary code” as encompassing anything in 0s and 1s in a computer would therefore also encompass values expressed in “trinary code,” as the latter term is used in the ’544 patent. However, the Court reasoned that “binary code” cannot include “trinary code,” as even the district court recognized. The ’544 patent claims and specification did not permit such an overlap, noted the Court. Accordingly, it concluded that the district court’s construction of “binary code” was “internally inconsistent and contradictory to the rest of the patent.” Id. at 12. To resolve this contradiction, the Court construed “binary code” as being limited to binary numbers and “trinary code” as being limited to trinary numbers. It explained that the “binary-coded trinary numbers” described by the district court were therefore trinary codes, not binary codes.

In light of its claim construction, the Federal Circuit vacated the preliminary injunction, noting that the errors in claim construction will fundamentally influence the likelihood of success in proving infringement, and remanded.