CAFC discusses preambles in COCHLEAR BONE ANCHORED v. OTICON MEDICAL AB

From the dissent of Judge Newman in Cochlear:



In finding the ’040 patent’s system obvious, the court
employs an improper analytic technique. The court first
removes major limitations from the claims, and then applies
selected pieces of prior art to the residue. This is
achieved by holding that the opening clause of all the
claims is “not limiting,” whereby the claims are freed of
critical limitations and are then held to embrace prior art
that is excluded from the ’040 system by the introductory
statement. My colleagues dispose of these limitations by
designating the introductory clause as a mere “preamble”
that does not limit the claims—although the clause states
limitations fundamental to the ’040 invention. It is incorrect
to remove such claim limitations when they describe
substantive aspects of the invention, and the error is compounded when,
as here, the court then broadens the residue of the claim into obviousness over prior art that is
disavowed by the preamble.

(...)

The opinion distorts the ’040 patent’s invention by stating: “Because the preamble is not limiting, [] there is therefore no limitation on the type of hearing loss to be treated
by the claimed hearing aid.” Maj. Op. at 16. It is, however,
stated throughout the patent documents that the ’040 invention is directed to unilateral hearing loss. See, e.g., ’040
patent, Abstract (“A hearing aid apparatus is intended
for . . . rehabilitation of patients with unilateral hearing
loss.”); ’040 patent, col. 1, ll. 5–11 (“The present invention
relates to a hearing aid . . . for rehabilitation of patients
with unilateral hearing loss.”). This is the invention for
which patentability is determined. See Jansen v. Rexall
Sundown, Inc., 342 F.3d 1329, 1333–34 (Fed. Cir. 2003)
(the preamble is a statement of the purpose of the invention).

(...)
The question of obviousness includes determining
whether the prior art suggests producing the claimed combination and with a reasonable expectation of success.
Here, no prior art suggests the combination that is described and claimed in the ’040 patent. It appears undisputed that at the time of this invention, transcranial
attenuation was not even considered in bone-anchored
hearing devices