embodiments, the specification and the prosecution history support only
one embodiment. Merely calling the embodiment "preferred" does not
broaden the claims beyond their support in the specification. See Wang,
197 F.3d at 1383.
Timken's second reason why limiting the claim to a zinc-nickel alloy is
inappropriate is that such an interpretation violates the doctrine of
claim differentiation. "Under the doctrine of claim differentiation, each
claim in a patent is presumptively different in scope." Intermatic Inc.
v. Lamson & Sessions Co., 273 F.3d 1355, 1364 (Fed. Cir. 2001). The
doctrine is "clearly applicable when there is a dispute over whether a
limitation found in a dependent claim should be read into an independent
claim, and that limitation is the only meaningful difference between the
two claims." Id. (citing Wenger Mfg., Inc. v. Coating Mach. Sys., Inc.,
239 F.3d 1225, 1233 (Fed. Cir. 2001)). Timken notes that in this case,
independent claim one discloses a zinc alloy plated roller element
bearing. Dependent claim seven, which depends on claim one, recites that
the zinc alloy is zinc-nickel. Thus, argues Timken, SKF's reading would
render the claim superfluous.
The court disagrees with Timken's argument. "Although the doctrine of
claim differentiation may at times be controlling, construction of claims
is not based solely upon the language of other claims; the doctrine
cannot alter a definition that is otherwise clear from the claim
language, description, and prosecution history." O.I. Corp. v. Tekmar
Co., 115 F.3d 1576, 1582 (Fed. Cir. 1997). See also Kimberly-Clark Corp.
v. Tyco Int'l, Civ. A. No. 00-1080, 2001 U.S. App. LEXIS 2734, at *11, 4
Fed. Appx. 946 (Fed. Cir. 2001). Indeed, "the doctrine of claim
differentiation is not a hard and fast rule of construction." Comark
Communs. v. Harris Corp., 156 F.3d 1182, 1187 (Fed. Cir. 1998).
Here, the patent specification repeatedly refers to a zinc-nickel
plating layer. The prosecution history also suggests that the zinc alloy
disclosed is the zinc-nickel plating of the Hsu '871 patent. The court
therefore interprets the term zinc alloy to mean the zinc-nickel plating
disclosed in the Hsu '871 patent, which is a zinc-nickel alloy comprising
about 80-94% by weight zinc.*fn3
The second step in a patent infringement action is to compare the
properly construed claim to the accused infringing device. See Markman, 53
F.3d at 976. In this case, the court has concluded that the zinc alloy
disclosed in the patent is the zinc-nickel alloy of the Hsu '871 patent,
namely a zinc-nickel alloy of 80-94% by weight zinc. Timken contends that
there is a question of fact as to whether SKF's bearing contains a
zinc-iron alloy. There are, however, no allegations that SKF's bearing
contains any amount of nickel so as to infringe upon Timken's product, as
defined by the court.
For the reasons set forth above, the court concludes that SKF's bearing
does not infringe upon the '860 patent and that summary judgment in favor
of SKF and against Timken is appropriate in this case.
An appropriate order follows.