Knowles Electronics LLC v. Cirrus Logic, Inc., 883 F.3d 1358

This appeal concerns PTAB decisions in an inter partes reexamination of U.S. Patent No. 6,781,231 (the '231 patent), which claims a MEMS microphone package that shields the microphone from interference and environmental conditions.
Claims 1–4 (original) recite a "package" formed by connecting a cover to a substrate to accommodate a MEMS microphone; proposed claims 23–27 added a limitation that solder pads are "configured to" attach to a PCB "using a solder reflow process."
The PTAB affirmed the examiner: (1) claims 1–4 were anticipated under the PTAB's construction of "package," and (2) proposed claims 23–27 lacked adequate written description because the specification did not specifically disclose solder reflow as the connecting method.
On appeal Knowles argued the PTAB mis-construed "package" (urging a narrower, mountable/self-contained meaning), erred on written description for the reflow limitation, and raised a late challenge to whether the Cirrus entities were proper real parties-in-interest.
The Federal Circuit affirmed: it upheld the PTAB's broadest-reasonable-interpretation construction of "package," found substantial evidence supported the PTAB's written-description rejection of the reflow limitation, and held Knowles waived its late objection to the real-party-in-interest change.

Issue	Knowles' Argument	Cirrus/PTAB Argument	Held
Proper construction of "package" in claims 1–4	"Package" requires a mountable, self-contained unit with a second-level connection (e.g., through-hole or surface mount)	"Package" may include assemblies with any type of second-level connection and is not limited to specific mounting methods	PTAB construction affirmed; intrinsic record does not limit "package" to Knowles' narrow meaning
Anticipation of claims 1–4	Anticipation challenge fails under Knowles' narrower construction of "package"	Under PTAB's construction prior art anticipates claims	Court declined Knowles' alternative construction and did not adopt its anticipation argument
Written description for proposed claims 23–27 (solder reflow limitation)	Specification plus art support would show PHOSITA understood pads were intended for reflow attachment	Spec only generically discloses solder pads; multiple methods existed and spec does not convey possession of reflow-specific pads	PTAB's written-description rejection affirmed on substantial evidence; reflow is a species not shown in spec
Real party-in-interest / participation of Cirrus entities	Objected that Cirrus entities were improper parties and challenged their participation	PTAB allowed change of real party-in-interest; Knowles chiefly objected to late participation at oral argument	Court finds Knowles waived belated challenge to real-party-in-interest; argument not preserved below

Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (2015) (subsidiary factual findings in claim construction reviewed for substantial evidence)
Microsoft Corp. v. Proxyconn, Inc., 789 F.3d 1292 (Fed. Cir. 2015) (priority of intrinsic evidence in claim construction)
In re CSB-Systems Int'l, Inc., 832 F.3d 1335 (Fed. Cir. 2016) (PTAB uses broadest reasonable interpretation in reexamination)
In re Bigio, 381 F.3d 1320 (Fed. Cir. 2004) (review of PTO claim term interpretations)
Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (written-description standard: specification must show inventor possessed claimed invention)
Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956 (Fed. Cir. 2002) (written-description inquiry and standard applied)
B & B Hardware, Inc. v. Hargis Indus., Inc., 135 S. Ct. 1293 (2015) (issue preclusion applies between agencies and courts absent statutory purpose to the contrary)
Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996) (claim construction is a legal question and uniformity is important)
Trans Texas Holdings Corp. v. Balance Point, 498 F.3d 1290 (Fed. Cir. 2007) (PTO not bound by district court claim construction in reexamination)