The court erred in its construction of the term “air quality” by
limiting the term to the “concentration of pollutants or contaminants
in the air. The ‘985 Patent
describes that the claimed monitoring system is for use in indoor
environments. Consistent with the understanding in the prior art at the
time the original application was filed in 1997, the person of ordinary
skill would have known that air quality in such environments includes
not only levels of pollutants or contaminants, but also temperature and
humidity values. Indeed, during the prosecution of the reissue
application, the Examiner confirmed that air quality attributes include
at least temperature and humidity.

The plain meaning of “air
quality” is exactly what the words connote: a quality of the air. That
term should not have been limited as was done by the district court,
particularly in light of the understanding in the art and the intrinsic
evidence in the reissue proceedings that “air quality” is a broad term
that includes numerous attributes. Thus, the court's “air quality”
construction is inconsistent with the prior art, the specification, and
the prosecution history. The court's erroneous construction of “air
quality” should be reversed and the construction proposed by PureChoice
should be adopted.

The court further erred when it concluded that
two other limitations were incapable of being construed and, hence,
indefinite. Those limitations, “sensor for measuring environmental air
quality data” and “air quality sensor adapted to measure non-weather
data,” are not insolubly ambiguous and can be given a reasonable
meaning consistent with the prior art, the patent's specification, and
the prosecution history.

For example, in relation to the term
“sensor for measuring environmental air quality data,” the court held
that limitation indefinite without considering that the limitation
incorporates the previously construed (albeit incorrectly) “air
quality” term. The district court compounded this error when it did not
even attempt to construe the term. Finally, the court erred when it
failed to consider what the person of ordinary skill would have known
in 1997 when the application was filed. This knowledge was represented
in the prior art considered by the Examiner during prosecution and
other undisputed prior art. Much of this prior art, discussed above,
was part of the patent's prosecution history and the Examiner's and
PureChoice's comments on that art establish that the court's “incapable
of being construed” conclusion is wrong as a matter of law.

As to
the final limitation of “air quality sensor adapted to measure
non-weather data,” the court committed the same errors discussed above.
The court appears to have relied on its incorrect construction of “air
quality, did not attempt to construe the term, and failed to consider
what the person of ordinary skill would have understood from the prior
art, the specification, and the prosecution history of the patent.

In
light of the district court's errors and its erroneous conclusion that
these claim limitations are incapable of construction, this Court
should reverse the district court and conclude that these claim terms
are definite. PureChoice's constructions of these terms should be
adopted.

1. The district court's construction of “air quality” is consistent
with the intrinsic evidence. PureChoice attempts to distance itself
from this evidence and instead asks the Court to construe the term in
the same manner as a few selected pieces of prior art, thereby ignoring
the intrinsic evidence. This is in direct contradiction to this Court's
plain instructions in
Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc),
cert. denied, 546 U.S. 1170 (2006).
The Court must look to the specification and prosecution history and
not rely primarily on “potential extrinsic evidence of some marginal
relevance.”
Phillips, 415 F.3d at 1318. The district court properly
analyzed the claim language in light of the intrinsic evidence, and its
construction of “air quality” as “a concentration of pollutants and
contaminants in the air” should not be reversed.

The
specification and prosecution history clearly demonstrate that the term
“air quality” means “a concentration of pollutants or contaminants in
the air.” The specification consistently discloses a system that
monitors for pollutants and contaminants, and it does not reference
temperature or humidity, or imply in any way that either of those is an
attribute of air quality. In fact, PureChoice cannot point to a single section in the patent indicating that either
temperature or humidity is included in the definition of “air quality.”
The specification's unambiguous definition of “air quality” as “a
concentration of pollutants or contaminants in the air” is dispositive.

The other intrinsic evidence supports this construction. In prosecuting its patent, PureChoice
twice disavowed the inclusion of temperature and humidity as
part of “air quality.” It unambiguously differentiated its patent from
the prior art Gilbert and Shelton patents by arguing that sensors that
monitor for temperature and humidity do not monitor for “air quality.”

Under
these facts, extrinsic evidence is irrelevant. However, if the Court
finds it necessary to turn to the extrinsic evidence to determine the
meaning of the word “air quality,” it will observe that the technical
dictionaries, the relevant rules and regulations, and expert testimony
all provide evidence that one of ordinary skill would interpret the
term to mean “a concentration of pollutants or contaminants.”

2.
The Court need not rule on the definition of “air quality” if it
determines that the district court was correct in ruling that “sensor
for measuring environmental air quality data” and “air quality sensor
adapted to measure non-weather data” are indefinite.^[FN3]
The phrases “sensor for measuring environmental air quality data” and
“air quality sensor adapted to measure non-weather data” are incapable
of construction. Neither is a term of art. The specification is
completely silent as to the meanings of these terms. They were added
during prosecution to avoid cited prior art, and the prosecution
history makes clear that the elements mean different things, yet those
different meanings are not explained. And, to the extent the Court
considers extrinsic evidence, this evidence confirms that one of
ordinary skill in the art would not know how to distinguish between the
two elements or otherwise interpret them.

FN3.
Honeywell is addressing the definition of “air quality” first as this
definition provides useful background for addressing the sensor terms.

Even
PureChoice is unable to propose a workable definition of these terms.
Instead, its definitions create more confusion. The definitions do not
reveal which attributes would fall into which category. PureChoice also
contends certain air quality attributes can be both “non-weather data”
and “environmental air quality data.” This contention contradicts the
one thing that is clear about these terms from the intrinsic evidence -
the sensors must monitor for different air quality attributes.

A person of ordinary
skill in the art, reading the claim terms in light of all the intrinsic
and even extrinsic evidence, would not be able to determine what the
terms mean. Accordingly, the terms are indefinite.