A Number Expressed As A Power Of Ten Represents An Ordinary Number, Not A Range Of Numbers

In U.S. Philips Corp. v. Iwasaki Electric Co., (No. 2007-1117; November 2, 2007), a Federal Circuit panel affirms-in-part, reverses-in-part, vacates-in-part and remands a district court’s claim construction ruling concerning a numerical range and application of the doctrine of equivalents to that numerical range, in a patent for high pressure mercury vapor discharge lamps filled with a mixture including a quantity of halogen between 10 -6 and 10 -4 μmol/mm 3 . The accused lamps have a halogen concentration of 1.6 +/- 0.4 x 10 -4, just above the claimed range. U.S. Philips argued that the upper limit “10 -4” term is different and less precise than 1 x 10 -4, and that the limitation should properly be construed to mean all values closer on a logarithmic scale to 10 -4 than to 10 -5 or to 10 -3, resulting in a range for the upper limit of approximately 3.2 x 10 -5 to 3.2 x 10 -4, thus capturing the accused lamp.

The Federal Circuit disagrees, concluding that the limitation is properly construed to mean between 1 x 10 -6 and 1 x 10 -4 μmol/mm 3 . The upper and lower limits are ordinary numbers, not ranges of numbers, even if expressed as powers of ten, and the specification fully supports such construction by treating 10 -5 as a synonym for 1 x 10 -5 . Thus, the district court’s construction of the claimed range as meaning “between 1 x 10 -6 and 1 x 10 -4” is affirmed.

The district court found, however, that the doctrine of equivalents was foreclosed as a matter of law, and granted summary judgment of noninfringement. The Federal Circuit disagrees, stating that a claim’s recitation of numeric ranges does not, by itself, preclude reliance on the doctrine of equivalents. Even though the asserted claimed range lacks terms like “approximately”, application of the doctrine is still proper, because such terms simply serve to expand the scope of literal infringement. Since there is no indication that the range limit was included during prosecution to avoid prior art , the Federal Circuit vacates the summary judgment of non-infringement, and remands for determination of infringement under the doctrine of equivalents.