Federal Circuit: The difference between substantial cure and full cure is not insubstantialAugust 22, 2008

In a decision yesterday, the Federal Circuit affirmed a grant of summary judgment of anticipation and obviousness. While the court disagreed with the district court's conclusion that the prior art expressly anticipated the asserted claims as a matter of law, the court did conclude that the prior art inherently disclosed the relevant limitations as a matter of law. Further, because the patentee's obviousness arguments were contingent on its anticipation arguments being successful, the court likewise affirmed the summary judgment of obviousness.

Interestingly, in a footnote the court noted that while the patentee challenged the district court's claim construction of one term in its brief, it conceded at oral argument that the issue of claim construction was not properly before the court because the patentee did not contend that the resolution of the anticipation issue depended on the construction of the term.

More on Leggett & Platt, Inc. v. VUTEk, Inc. after the jump.

Leggett & Platt, Inc. owns a patent relating to printing on deformable substrates. In 2005, L&P sued VUTEk, Inc. for infringement. VUTEk claimed the asserted claims were anticipated by, or obvious in light of, VUTEk's prior patents, 6,457,823 and 6,616,355. Following a Markman hearing, the parties filed cross-motions for summary judgment, with VUTEk alleging anticipation of claims 1, 9, 10, and 19 by VUTEk's '823 patent and obviousness of claims 2, 3, and 7 in light of VUTEk's '823 and '355 patents. The district court granted VUTEk's motion, prompting L&P's appeal.

L&P's patent describes the use of ink which could be "substantially cured" through the use of ultraviolet (UV) radiation, thereby avoiding the use of infrared radiation which may deform an infrared sensative surface. The VUTEk '823 patent described the use of UV radiation to "set" ink in an inkjet printer, "so that the ink does not spread or ball up, even though it is still in a quasi-fluid state."At issue was whether the UV radiation in the VUTEk patent was capable of "substantially curing" the ink, and therefore had inherently disclosed the limitation of the L&P patent.

The district court interpreted the term "substantially cure" in L&P's claim 1 to mean "cured to a great extent or almost completely cured." At the slowest operating speed of VUTEk's product disclosed in the '823 patent, the UV radiation would cure the ink 75-80%, more curing than was required to set the ink during normal operating speed. While the Federal Circuit held it could not state, under the summary judgment standard, that 75-80% was "substantial" as a matter of law, a person having ordinary skill in the art could conclude that more exposure of the ink to UV radiation would result in a additional curing beyond 80%, to the limit of "substantial."

L&P argued that, at the time of the '823 invention, LED's (as used in the VUTEk and L&P inventions) were unable to emit sufficient radiation to cure the ink. The court was not persuaded "by L&P's repeated efforts to conflate 'substantially cure' and simply 'cure.'" As stated by the court: "the difference between substantial cure and full cure is not insubstantial." Absent evidence of the extent of curing required to meet the "substantial" threshhold and the limitations of contemporary LED's, the court rejected L&P's argument. Speficially, the court noted (internal citation omitted): "the '823 patent teaches that, if a UV radiation source is passed over the ink at a slower speed and/or multiple times, the degree to which the ink is cured will increase. One of ordinary skill in the art, reading this disclosure, could only conclude that more passes and/or a slower carriage speed would result in an inceasing degree of cure, albeit not linearly increasing." Accordingly, the court held that, as a matter of law, VUTEk's '823 patent inherently disclosed the "substantially cured" limitation, and therefore inherently anticipated several claims of the asserted patent.

L&P's arguments against obviousness depended on its arguments against anticipation, and so the court likewise affirmed the finding of obviousness of the remaining asserted claims.

To read the full decision in Leggett & Platt, Inc. v. VUTEk, Inc., click here.

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