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Another preliminary injunction vacated on appeal, this time because of claim construction

February 22, 2008
Post by Blog Staff

For a second time this week, the Federal Circuit vacated a preliminary injunction entered by a district court. This time, the court found the district court's claim construction too broad, and under the courts revised, narrower construction, found that the plaintiffs were not likely to succeed on the merits of the case. As a result, the Federal Circuit vacated the injunction and remanded the case.More detail of Chamberlain Group, Inc. v. Lear Corp. after the jump.Chamberlain owns a patent directed to garage door openers and, along with its exclusive licensee, sued Lear for infringement. After a Markman hearing, the district court issued a preliminary injunction, finding the plaintiffs likely to succeed on the merits of their infringement claim, and that the other equitable factors favored granting an injunction. The claimed garage door system comprises a transmitter and a receiver that communicate via encrypted signals on a radio frequency carrier. The signal includes variable code and fixed code, which are compared to a stored code to activate the door opener. The patent improves on prior art garage door openers with an enhanced encryption system to make cracking the code more difficult for would-be techno-burglars.The key claim construction issue is the interpretation of the word "code." The claim uses the terms "binary code" and "trinary code." The district court defined 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." The district court clarified that "binary code" does not encompass "trinary code."Lear characterized its transmitter as using only trinary numbers and algorithms, therefore operating in trinary code rather than binary code. Lear conceded that a trinary number is still represented by zeros and ones in a computer, and all parties agreed that all computers necessarily operate in binary code. Thus, the district court characterized Lear's trinary number as a binary-coded trinary number, and thus concluded that Lear satisfied the binary code limitation of the claim.The Federal Circuit concluded that the district court erred in construing the claim term "binary code," vacated the preliminary injunction, and remanded. The opinion provides an esoteric discussion of math and electronics, including various numerical base systems and computer use of binary systems, citing the judicial explanation of such systems by the Supreme Court in Gottschalk v. Benson.The Federal Circuit first commended the district court for following the rules for claim construction, weighing the intrinsic evidence along with extrinsic evidence, and properly seeking to avoid importing limitations from the specification in the claims, while giving the term "binary code" its ordinary and customary meaning. Nonetheless, the court concluded the district court misinterpreted the term because the specification gave a particular limiting meaning to "binary code" narrower than the ordinary and customary meaning.The Federal Circuit discussed the district court's interpretation that binary code could serve as a medium to express binary (base 2) numbers, trinary (base 3) numbers, decimal (base 10) numbers, or any other base. The court noted that the significance of this distinction depends on an examination of the operation of binary and trinary number systems in a computer, which was then discussed in some detail. The Federal Circuit reasoned that the district court's construction of "binary code" was internally inconsistent and contradictory with the patent. To resolve this contradiction and preserve the independent meaning of "binary code" as compared to "trinary code," the Federal Circuit read "binary code" as limited to binary numbers and "trinary code" as limited to trinary numbers because the substance, rather than the form, controls whether a "code" is binary or trinary for the patent. The court thus concluded that the "binary-coded trinary numbers" are trinary codes and not binary codes.With respect to the preliminary injunction, the grant or denial is reviewed for abuse of discretion. Where a district court relies on an erroneous claim construction in granting a preliminary injunction, the legal error may constitute an abuse of discretion requiring the court to vacate the injunction. A correct claim construction is almost always a prerequisite for imposition of a preliminary injunction. Errors in claim construction will fundamentally influence the likelihood of success in proving infringement, and thus, the district court's erroneous construction of the disputed claim term required the Federal Circuit to vacate the preliminary injunction.To read the full decision in Chamberlain Group, Inc. v. Lear Corp., click here.


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