The case Altair Engineering, Inc. v. LEDdynamics, Inc. centered on the claim construction of Altair’s US Patent No. 7,049,761 (“the ‘761 patent”) which discloses a light tube that utilizes light emitting diodes (“LEDs”).[i] Specifically, the LEDs were “to serve as a replacement for the typical fluorescent tube lights commonly used in schools and offices.”[ii]

During the Markman hearing,[iii] the only disputed term was “closely-spaced” in reference to the position of the LEDS within the tube.[iv] LEDdynamics asserted that the term meant, “[N]ot spaced-apart, such that adjacent LEDs are sufficiently close that another LED cannot fit in the space therebetween.”[v] However, Altair argued that the term meant, “[M]ultiple LEDs arranged inside of a bulb portion where the number and spacing of the LEDs is such that, when lighted, the LEDs produce an illumination level and effect which adequately performs as a fluorescent light tube substitute.”[vi] The District Court agreed with LEDdynamics’ construction, upon which LEDdynamics moved for summary judgment of non-infringement.[vii] Up to this point, Altair had asserted that the allegedly infringing product contained 36 LEDs; however, under the District Court’s adopted construction of “closely-spaced,” that assertion supported non-infringement. Therefore, Altair altered course and asserted that the 36 LEDs were in fact 36 six packs of LEDs, which resulted in a total of 216 LEDs.[viii] The Court found Atlair judicially estopped from making that argument since the proceedings had relied on Altair’s earlier definition of LEDs and a change now would prejudice LEDdynamics.[ix] Altair appealed both that decision and the claim construction.[x]

Upon appeal, the Federal Circuit upheld the claim construction, but reversed the summary judgment decision based on the improper use of judicial estoppel.[xi] First resolving the claim construction issue, the Federal Circuit found support in the District Court’s construction in the prosecution history.[xii] Originally the claim at issue was drafted without the “closely-spaced” language, but Altair inserted the limitation to avoid running aground of a prior art reference.[xiii] Additionally, Altair distinguished itself from another prior art reference that was “spaced-apart” by asserting the “closely-spaced” language.[xiv] The Federal Circuit found these instances supported the District Courts claim construction.

Turning to the issue of judicial estoppel, the Federal Circuit looked to the Supreme Court to outline the proper test.[xv] Judicial estoppel is used to prevent “a party from prevailing in one phase of the case on an argument and then relying on a contradictory argument to prevail in another phase.”[xvi] In this case, the Federal Circuit noted, “Altair did not prevail in any phase,” but in fact “lost its argument on claim construction.”[xvii] As a result, judicial estoppel was improper, and the Federal Circuit, now finding a genuine issue of material fact, reversed the summary judgment decision.[xviii]