Ex Parte 5573648 et al

Board of Patent Appeals and Interferences

May 23, 2007

90006208 (B.P.A.I. May. 23, 2007)

The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
_______________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________

Ex parte Atwood Mobile Products, Inc.
_______________

Appeal 2007-0128
Reexamination Control 90/006,208
Patent 5,573,648
Technology Center 1700
_______________

Decided: May 23, 2007

Before RICHARD TORCZON, SALLY G. LANE, and MICHAEL P. TIERNEY,
Administrative Patent Judges.

TIERNEY, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on an appeal under 35 U.S.C. '' 134 and 306 (2006) from
the Examiner's final rejection of claims 1, 3-16, 75, 79, and 80 in the
above-identified reexamination proceedings. (Examiner's Answer mailed July 17,
2002; Final Office Action mailed December 16, 2002; Appeal Brief. filed April 21,
2003; Reply Brief filed September 17, 2003).
We affirm.

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REEXAMINATION
A request for reexamination was filed on January 29, 2002 by Third Party
Requester Figaro Engineering for reexamination of U.S. Patent 5,573,648 (the
>648 patent) issued November 12, 1996 to Yousheng Shen, Franco Consadori and
D. George Field. The >648 patent is assigned to Atwood Mobile Products, Inc.,
hereinafter AAtwood.@

I. STATEMENT OF THE CASE
The invention relates to gas sensors. As explained in the background section
of the '648 patent, it is well known that carbon monoxide (CO), reacts with
moisture in the air at room temperature and forms protons, electrons and carbon
dioxide (CO2) in an oxidation reaction of CO. ('648, col. 1, ll. 24-30). Conversely,
it is also known that there is a moisture formation reaction where protons, electrons
and oxygen combine in a reduction reaction to form water. ('648, col. 1, ll. 31-36).
Through the use of these two reactions, prior art gas sensors utilizing a proton
conductor were able to detect the presence of carbon monoxide. The '648 patent
alleges however, that prior art sensors were complicated and required periodic
maintenance. ('648, col. 2, ll. 12-14 and 23-25).
Of the claims on appeal, only claims 1 and 79 are independent claims. Each
of the independent claims is directed towards electrochemical gas sensors for the
quantitative measurement of a gas in an ambient atmosphere. (Appeal Br.,
Appendix, preamble of claims 1 and 79). The gas sensors comprise a sensing
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electrode, a counter electrode and a protonic conductive electrolyte membrane
situated between, and in contact with, the sensing and counter electrodes. The
sensing and counter electrodes each have a diameter in the range of approximately
1 mm to 15 mm and the membrane has a thickness in the range of approximately
0.1 mm to 1 mm. The sensing and counter electrodes are mixed ionic-electronic
conductive electrodes containing both an electronic conducting material and an
ionic conducting material.
The Examiner has rejected Atwood's claims setting forth four (4) prior art
rejections. Generally, the Examiner takes the position that the prior art teaches gas
sensors using a sensor electrode and a counter electrode with an
electrolyte membrane between the two electrodes, i.e., a membrane and electrode
cell. The Examiner acknowledges that no single reference relied upon by the
Examiner teaches the use of the gas sensor with Atwood's claimed mixed
conductive electrodes formed from an electronic conducting material and an ionic
conducting material. The Examiner states however, that the prior art describes the
mixed electrodes as suitable for use in gas sensors and identifies the benefits of
such electrodes, e.g., such electrodes have a uniform electrode structure which uses
a relatively small loading of catalyst. (Grot U.S. Pat. 5,330,860, col. 3, ll. 49-57).
Atwood disagrees with the Examiner's rejections. Atwood generally argues
that the Examiner has relied upon non-analogous art and that there is no motivation
to combine the prior art in the manner suggested by the Examiner.

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We affirm the Examiner’s prior art rejection of Atwood claims 1, 3-16, 75,
79 and 80.

II. ISSUE
The issue is whether Atwood has shown that the Examiner erred in rejecting
the claims on appeal under 35 U.S.C. ' 103(a) (2004). The issue turns on the
following:

i. Whether the prior art teachings can be combined to establish that one
skilled in the art would have made Atwood=s claimed gas sensors;
and
ii. Whether Atwood=s alleged commercial success for Atwood=s
licensed gas sensors rebuts the Examiner=s prima facie case of
obviousness.

III. FINDINGS OF FACT
A. The Claims Under Reexamination
1) Claims 1, 3-16, 75, 79, and 80 were finally rejected by the Examiner and are
on appeal. (Examiner=s Answer, Paper 20, p. 2).

2) Claims 2, 17-74 and 76-78 were indicated as allowable by the Examiner.
(Id.).

3) Claim 1 is representative of the claims on appeal and reads as follows:
An electrochemical gas sensor for quantitative measurement of a gas
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in an ambient atmosphere comprising:
a porous mixed ionic-electronic conductive sensing electrode

having both an electronic conducting material and an ionic conducting
material;
a porous mixed ionic-electronic conductive counter electrode
having both an electronic conducting material and an ionic conducting
material;
a first protonic conductive electrolyte membrane in between
and
in contact with the sensing and counter electrodes, and having a
thickness in the range of approximately 0.1 mm to 1 mm;
the sensing electrode reacting with the gas to produce a change
in an electrical characteristic between the sensing electrode and the
counter electrode;
means for electrical measurement;
said sensing and counter electrodes each having a diameter in
the range of approximately 1 mm to 15 mm, and being electrically
connected to said electrical measurement means;
whereby, in a positive ambient concentration of said gas, said
electrical measurement means detects changes in said electrical
characteristic.

4) Atwood=s specification describes a “means for electrical
measurement” as a voltage meter that measures potential differences
between electrical leads. (>648 patent specification under reexamination,
col. 6, ll. 8-10 and col. 8, ll. 11-13).

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B. Prior Art
i. Dempsey, U.S. Patent 4,227,984
5) Dempsey '984 is directed to a membrane and electrode cell for detecting
gases. Specifically, Dempsey's abstract states:
A compact electrochemical gas sensing cell is described for detecting
gases such as carbon monoxide, NO2, alcohol vapors, etc. The cell is
characterized by temperature stability during zero-air operation so that
background current with no gas flow is eliminated or minimized. This
cell utilizes a hydrated, solid polymer electrolyte having reference,

sensing and counter electrodes mounted on the surface thereof with
one side of the membrane being flooded with distilled water to
provide self-humidification of the cell by water vapor transport across
the membrane.

(Dempsey '984, abstract).

6) Dempsey teaches that the membrane and electrode gas sensor is Abased on
the oxidation or reduction of the constituent to be detected at the catalytic sensing
electrode.@ (Id. at col. 2, ll. 36-40).

7) Dempsey identifies the following reactions when measuring carbon
monoxide:
i. Sensing Electrode: CO + H2O = CO2 + 2H+ = 2e-

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ii. Counter Electrode: 2H+ + 2e- = H2 or 2H+ + 2 O2 + 2e- = H2O
(Id. at col. 2, line 65 to col. 3, line 5).

8) Dempsey=s gas sensor comprises a sensing electrode, a membrane, and a
counter electrode with the electrodes connected by a potentiostatic circuit.
Specifically, Dempsey states:

The various objectives and advantages of the invention are realized in
an electrochemical gas sensor of the solid polymer electrolyte type in
which the sensing and reference electrodes are mounted in close
proximity preferably on one side of a membrane. These electrodes
and a counter electrode on the other side of the membrane are
interconnected by a potentiostatic circuit which maintains the
potential
at the sensing electrode at the desired level for optinum [sic] oxidation
or reduction of the gaseous constituent to be sensed and maintains a
fixed potential difference between it and the reference electrode. The
electrodes are made similar in chemical and electrochemical structure
and are secured to the membrane in an identical fashion. The
reference and sensing electrodes though mounted in close proximity
on the membrane are situated so that the reference electrode is not in
the current flux field due to the current driven from the counter to the
sensing electrode by the potentiostatic circuit thereby eliminating
conditions which give rise to large background current variations with
temperature during zero-air operations.

(Id. at col. 1, line 61 to col. 2, line 13).

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9) For carbon dioxide, Dempsey explains that:
It may be seen from the above reactions that as carbon monoxide is
oxidized to carbon dioxide, electrons are released which flow in the
external circuit and hydrogen ions are transported through the
electrolyte (along with some water molecules) to the counter electrode
and are reduced there to form molecular hydrogen or water. The
current flowing in the external circuit as a result of this rapid
oxidation of carbon monoxide is thus directly proportional to the
carbon monoxide concentration.

(Id. at col. 3, ll. 6-15).
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10) Dempsey Figure 1, provided below, depicts Dempsey=s membrane and cell
gas sensor:

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Dempsey identifies various portions of Figure 1 including the following
parts:
1 Reservoir
2 Distilled Water
3 Gasket
5 & 6 Hydrated Ports
7 Water Channel
8 Hydrated solid polymer electrolyte (SPE) cation exchange membrane
10 Counter electrode
11 Catalytic reference electrode
13 Sensing electrode
14 Sensing port
15 Bottom plate
16 & 17 Opening and barrier film to permit passage of air while blocking
CO

(Id. at col. 4, line 30 to col. 5, line 21).

11) Dempsey states that a method of forming gas sensing electrodes is
Adescribed in detail in U.S. Pat. No. 3,134,697, entitled >Fuel Cell,= issued May
26, 1964.@ (Id. at col. 7, ll. 18-25).

12) Dempsey also teaches that the Anature and characteristics@ of the electrodes
is described in AU.S. Pat. No. 3,297,484, entitled >Electrode Structure and Fuel
Cell Incorporating the Same,= issued Jan. 10, 1967.@ (Id. at col. 8, ll. 31-44).

13) Dempsey exemplifies sensing and counter electrodes having a 1.6 cm
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diameter and a 0.6 mm thick membrane. (Id. at col. 11, ll. 58-67).

14) Dempsey does not describe Atwood=s claimed mixed ionic-electronic
conductive electrodes.
ii. Grot, U.S. Patent 5,330,860
15) Grot describes a membrane and electrode structure. (Grot ‘860, Title
"Membrane and electrode structure.").

16) Grot teaches that membrane and electrode cells are well known in the art and
are useful for a variety of purposes, including fuel cells and gas sensing devices.
Specifically, Grot states that:
So-called "M & E cells" are electrochemical cells employing a
membrane and electrode structure. Such cells can be operated as an
electrolytic cell for the production of electrochemical products, or
they may be operated as fuel cells for the production of electrical
energy, gas generating devices and processes, chemical synthesis
devices, chemical treatment and processing devices and methods, gas
dosimeters and sensing devices and the like. Electrolytic cells may,
for example, be used for the electrolysis of an alkali metal halide such
as sodium chloride or for the electrolysis of water. M & E cells are
well known in the art.

(Id. at col. 1, ll. 19-30).

17) Dempsey identifies U.S. Pat. 3,297,484 (>484) and U.S. Pat. 3,134,697
(>697) as describing electrodes for gas sensors. Grot identifies the >484 and >697
patents, as well as others, as suffering from problems. Specifically, Grot states
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that:
In all of the foregoing techniques, it has been necessary to utilize

liquid-based emulsion and several processing steps to form film of the
electrode material and thereafter bind or press the sheet of electrode
material upon the ion exchange membrane, or it has been necessary to
use binders and substantial quantities of expensive catalyst materials
to prepare membrane and electrode structures. It has also been
necessary to utilize large loadings of catalyst to make acceptable
electrodes in these prior art methods. The process for preparing the
electrodes using prior art ink compositions is inefficient and the
reproducibility is poor.

****

By prior art techniques, it has been impossible to prepare membrane
and electrode structures having loadings of the unsupported catalyst
materials as low as 3.0 mg per cm2 or even lower with no compromise
in the integrity of the membrane or the performance of the membrane
and electrode structure in various fuel cells, gas generating systems
and other devices.

(Grot >860, col. 1, line 40 to col. 2, line 14 and col. 3, ll. 4-15).

18) Grot '860 states that its membrane and electrode cell represents and
improvement over prior art cells and that its electrodes have "excellent
characteristics." (Id. at col. 3, ll. 49-62). Grot specifically identifies the benefits of
Grot’s electrodes as follows:
The electrode ink is printed, coated or bonded onto the surface of the
membrane by methods known in the art. The ink readily adheres to
the membrane thereby reducing the likelihood of delamination of the
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electrode structure, uniform application of the electrode layer,
reduction in the formation of gas bubbles at the membrane/electrode
interface and without adversely effecting the strength, dimensional

stability or electrical properties of the membrane. Unlike prior art
membranes the suspension medium reduces the viscosity of the ink,
suspends or dissolves the polymer but does not interact with the
functional groups of the polymer which may reduce the ionic
conductivity of the membrane and electrode structure.

(Id. at col. 4, ll. 15-29).
19) Grot’s electrode contains catalytically active particles and binders. (Grot,
col. 3, line 60 to col. 4, line 14).

20) Grot states that NAFION® is a preferred binder. (Id.).

21) Grot describes its catalytically active particles as follows:
The electrode layer can be made from well-known catalytically active
particles or materials. The anode is preferably formed by one or more
platinum group metal such as platinum, ruthenium, rhodium, and
iridium and electroconductive oxides thereof, and electroconductive
reduced oxides thereof. The cathode is preferably formed by one or
more of iron, nickel, stainless steel, a thermally decomposed product
of a fatty acid nickel salt, Raney nickel, stabilized Raney nickel,
carbonyl nickel and carbon powder supporting a platinum group
metal. The catalyst may be supported or unsupported. The preferred
catalyst is a platinum catalyst (manufactured by Precious Metals
Corp.), particularly 20% platinum on a carbon support known as
VULCAN7 (manufactured by Cabot Corp.).

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(Id. at col. 4, line 56 to col. 5, line 2, bold emphasis added).

22) Grot has three independent claims, claims 1, 11 and 12.

23) While Grot claim 11 is limited to a fuel cell, Grot claims 1 and 12 are not.
Specifically, the preambles of Grot independent claims 1, and 12 are as follows:
1. "An electrode composition comprising:"
12. "A membrane and electrode structure comprising:"

(Id. at claims 1, and 12).

iii. Uchida, U.S. Patent 5,474,857
24) Uchida teaches that solid polymer electrolytes can be used in gas sensors.
Specifically, Uchida states:
In addition, the assembly of the solid polymer electrolyte and the
electrode of the present invention can be effectively applied to
generators or purifiers of gases such as oxygen, ozone and hydrogen
and various gas sensors such as oxygen sensors and alcohol sensors.

(Id. at col. 10, lines 60-64).

25) Uchida teaches that its electrodes contain at least a noble metal catalyst, a
carbon powder and a solid polymer electrolyte. (Id. at col. 3, lines 46-56).

26) Uchida describes the following “conventional” membrane and electrode cell:
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First, carbon powders on which 10-25% by weight of a platinum
catalyst was supported were mixed with carbon powders subjected to
water repelling treatment with addition of 25-70% by weight of PTFE.

The resulting mixed powders for catalyst layer were sprinkled on a
carbon paper to which 20-60% by weight of a fluoropolymer was
added and this carbon paper was hot pressed at 340o - 380o C. under a
pressure of 5-20 kg/cm2 to make an electrode.

Addition of the solid polymer electrolyte to this electrode was carried
out by coating a solution prepared by mixing 2 ml of isopropyl
alcohol with 0.05-1.5 g of Nafion solution on the catalyst layer with
being sucked from the carbon paper side by a pump and drying the
coat. The thus produced electrodes were bonded to a solid polymer
membrane in the same manner as in Example 1 to make cell X.

(Id. at col. 7, line 55 to col. 8, line 7).

27) Uchida claims 1-18 and 21 recite or depend from claims that are directed to
fuel cells and their manufacture.

28) Uchida claims 19 and 20 make no mention of Afuel cells@ and instead are
directed towards a Asolid polymer electrolyte membrane and electrode assembly.@
(Uchida, claim 19 and 20 preamble).

iv. Vanderborgh, U.S. Patent No. 4,804,592
29) Vanderborgh describes electrodes for use in electrochemical cells with the
electrode comprising an ion conducting material, an electron conducting material
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and an electrocatalyst. (Vanderborgh, Abstract).

30) Vanderborgh teaches that its electrodes can be used in fuel cells or other
devices that require electrochemical generation of electrical power from reacting
gases. Specifically, Vanderborgh states:
Throughout the description, the composite electrode of the present invention
has been characterized as suitable for assembly in a fuel cell, such as a
hydrogen/oxygen fuel cell. As will be evident to those skilled in the art, the
composite electrode of the present invention can be utilized in
electrochemical devices which produce electrical power or chemical
compounds. For example, the present invention is applicable to systems
wherein water in liquid or vapor state is electrolyzed to generate hydrogen
and oxygen, to the synthesis of chlorine which is driven by electrical energy,
or to the synthesis of other materials of commercial interest, such as the
production of organic acids from alkanes. In general, the present invention
can be utilized to fabricate electrodes useful for the electrochemical
generation of electrical power from the consumption of reacting gases or
liquids or the electrochemical generation of chemical compounds from the
consumption of electrical power.

(Id. at col. 11, ll. 20-38).

31) Vanderborgh states that a goal of its invention is to provide a composite
electrode that uses the electrocatalyst more efficiently. (Id. at col. 3, ll. 51-55).

32) Vanderborgh teaches that it was known in the art to use composite electrodes
of ion exchange polymers, metals or carbon compounds and electrolytical
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compounds to form an electrode having a “three-phase interface to minimize
internal resistance to transport.” (Id. at col. 2, ll. 36-43).

33) Vanderborgh describes a suitable composite electrode as follows:
In one embodiment, the composite electrode 13 of the present
invention is formed of three separate layers or zones as illustrated
generally in FIG. 2 as 22, 24, and 26. Each layer or zone comprises a
mixture of carbon black, platinum or other suitable electrocatalyst
dispersed and supported on carbon black, polytetrafluoroethylene as a
binder, and a suitable ionic conducting material, such as
polyperfluorosulfonic acid. Suitable carbon black for use in
manufacturing the composite electrode of the present invention
possesses a relatively high surface area, a high electrical conductivity,
and a low chemical reactivity. Vulcan XC-72 ® manufactured by
Cabot Corporation is a preferred carbon black. It is preferred to utilize
a relatively high surface area platinum (e.g., 20 m2/gm) in the form of
a carbon black with approximately 15 wt % platinum loaded on the
surface thereof.

(Id. at col. 8, ll. 13-28).

v. LaConti, U.S. Patent No. 4,820,386
34) LaConti is directed to a sensor cell for the detection of carbon monoxide and
other oxidizable or reducible gases. (LaConti, Abstract).

35) LaConti=s gas sensor is a three-electrode hydrated proton-conducting
membrane cell having sensing, counter and reference electrodes. (Id. at col. 2, ll.
28-40).
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36) LaConti Table I lists a variety of gases that can be detected including carbon
monoxide, nitric oxide, alcohol, hydrogen, oxides of sulfur, hydrogen sulfide,
chlorine, bromine and oxygen. (LaConti, Table 1).

vi. Tomantschger, U.S. Patent 5,302,274
37) The Examiner states that Dempsey, Grot and Uchida fail to Aexplicitly recite
the use of a hydrated metal oxide protonic conductor electrolyte.@ (Examiner=s
Answer, p. 7).

38) Tomantschger teaches a gas sensor cell for quantitative measurement of
volatile gas components. (Tomantschger, abstract).

39) Tomantschger states that a specific gas sensor cell system can be devised
using suitable catalysts and electrolytes to test for any toxic, combustible or
flammable gas. (Id. at col. 2, ll. 42-46).

40) Tomantschger’s gas sensor cell comprises a sensing electrode and a counter
electrode on either side of an ion conductive electrolyte. (Id. at abstract).

41) Tomantschger teaches that the sensor and electrolyte are chosen to produce a
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change in electrical characteristic of the sensor electrode with respect to the
counter

electrode in the presence of a gas to be measured. (Id. at col. 5, ll. 20-25).

42) Tomantschger states that the ion conductive electrolyte may be a solid or
polymer electrolyte. (Id. at abstract).

43) Tomantschger states that the electrolyte material may be an ionically
conductive solid material, such as uranyl hydrogenphosphate tetrahydrate. (Id. at
col. 8, ll. 34-38).

vii. Razaq, U.S. Patent No. 5,322,602
44) Razaq describes a gas sensor formed with a perfluorinated, ion-exchange
polymer. (Razaq, Abstract).

45) Razaq states that its gas sensor can detect a wide variety of gases, include
moisture (H2O). (Id.).

IV. ANALYSIS
There are four (4) prior art rejections on appeal. The rejections are as
follows:
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i. Claims 1, 3-6, 8, 9, 13-16, 75, 79 and 80 are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Dempsey in view of Grot, Uchida
and/or Vanderborgh.

ii. Claim 7 is rejected under 35 U.S.C. § 103(a) as being unpatentable

over Dempsey in view of Grot, Uchida or Vanderborgh and further in
view of Tomantschger.

iii. Claims 10 and 11 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Dempsey in view of Grot, Uchida or Vanderborgh
and further in view of LaConti.

iv. Claim 12 is rejected under 35 U.S.C. § 103(a) as being unpatentable
over Dempsey in view of Grot, Uchida or Vanderborgh and further in
view of Razaq.

(Examiner=s Answer, pages 3-7). Before addressing the merits of the individual
rejections, we first construe the claims.

A. Claim Construction
Atwood=s independent claim 1 contains Ameans for@ language.
Specifically, the claims require a Ameans for electrical measurement@ and a
Ameans . . . for exposing a surface of said counter electrode to water.@ A claim
limitation that employs the language Ameans ... for@ invokes a rebuttable
presumption that ' 112, &6 applies.1 CCS Fitness, Inc. v. Brunswick Corp., 288
F.3d 1359, 1369, 62 UPQ2d 1658, 1664 (Fed. Cir. 2002).

135 U.S.C. 112, 6th paragraph (2006) reads as follows:
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In construing a means plus function claim limitation, the recited function
must first be identified. Then, the written description must be examined to
determine the structure that corresponds to and performs that function. ACTV Inc.
v. Walt Disney Co., 346 F.3d 1082, 1087, 68 USPQ2d 1516, 1520 (Fed. Cir. 2003).
Atwood=s independent claims recite a Ameans for electrical measurement.@
The function of this means is to measure the concentration of the gas being
detected. As to the structure that performs this function, Atwood=s specification
states that an electrical sensing means is used to measure the carbon dioxide
concentration response of a button sensor. (‘648, col. 8, ll. 11-13). The electrical
sensing means referred to is a voltage meter. (Id., Fig. 5, part 142). Atwood=s
specification states that a voltage meter measures potential differences between
electrical leads. (Id. at col. 6, ll. 8-10).
We construe Atwood=s claimed Ameans for electrical measurement@ to
encompass, at least, an electrical circuit having a voltage meter. We note that
Dempsey describes the use of a potentiostatic circuit that senses the voltage

An element in a claim for a combination may be expressed as a means
or step for performing a specified function without the recital of
structure, material, or acts in support thereof, and such claim shall be
construed to cover the corresponding structure, material, or acts
described in the specification and equivalents thereof.

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between the reference and sensing electrode and compares it to a preset value to
measure the concentration of the gas being sensed. (Dempsey, col. 9, Fig. 3, ll. 21-
36).

B. The Rejection of Claims 1, 3-6, 8, 9, 13-16, 75, 79 and 80 under 35
U.S.C. 103(a) as being unpatentable over Dempsey in view of Grot,
Uchida and/or Vanderborgh.

The ultimate determination whether an invention would have been obvious
under 35 U.S.C. §103 is a legal conclusion based on underlying findings of fact.
KSR Int’l v. Teleflex Inc., No. 04-1350, p. 23 (Apr. 30, 2007). Specifically,
obviousness is a question of law based upon underlying findings of fact with the
factual inquiry including: (1) the scope and content of the prior art; (2) the level of
ordinary skill in the prior art; (3) the difference between the claimed invention and
the prior art; and (4) objective evidence of nonobviousness. Graham v. John
Deere Co., 383 U.S. 1, 17-18, 148 USPQ 459, 460 (1966).
In addressing the findings of fact, “[t]he combination of familiar elements
according to known methods is likely to be obvious when it does nothing more
than yield predictable results.” KSR at 12. In particular, where the general
conditions of the claims are disclosed in the prior art, it is not inventive to discover
the optimum or workable ranges by routine experimentation. In re Aller, 220 F.2d
454, 456, 105 USPQ 233, 235 (CCPA 1955). As explained in KSR, “[a] person of
ordinary skill is also a person of ordinary creativity, not an automaton.” KSR at 17.
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On appeal, Applicants bear the burden of showing that the Examiner has not

established a legally sufficient basis for combining the teachings of the prior art.
Applicant may sustain their burden by showing that where the Examiner relies on a
combination of disclosures, the Examiner failed to provide sufficient evidence to
show that one having ordinary skill in the art would have done what Applicant did.

United States v. Adams, 383 U.S. 39 (1966); In re Kahn, 441 F.3d 977, 987-988,
78 USPQ2d 1329, 1336 (Fed. Cir. 2006).
Atwood argues that the claims on appeal do not stand or fall together. We
begin our analysis by reviewing the Examiner=s rejection of Atwood claim 1 as it
is best represents the claims on appeal.

Claim 1
The Examiner states that Dempsey teaches all limitations recited in Atwood
claim 1, except that Dempsey fails to teach the use of Atwood=s claimed mixed
ionic-electronic conductive electrodes. (Examiner=s Answer, p. 4).2 The

2 Note the Examiner finds that Atwood’s claimed electrode diameter range of
approximately 1 to 15 mm encompasses Dempsey’s 16 mm diameter electrodes.
(Answer, p. 4).

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Examiner cites Grot, Uchida and Vanderborgh as teaching the use of electrodes
having Atwood=s claimed combination of proton conducting material and electron

conducting materials. (Id.). The Examiner concludes that one of ordinary skill in
the art would have employed the electrodes of Grot and Uchida in Dempsey=s gas
sensor because Grot and Uchida teach the use of their electrodes in gas sensors and
because Grot and Uchida=s electrodes provide Dempsey=s gas sensor with
improved
electrical properties. (Id. at 5). Further, the Examiner states that Vanderborgh’s
teaches that its electrode provides improved properties and that the substitution of
one known electrode composition for another, when the results are not unexpected,
would have required only routine skill in the art. (Id.). Atwood disagrees.
Atwood=s arguments are addressed below.

i. Analogous Art
Atwood argues that Grot, Uchida and Vanderborgh represent non-analogous
art. (Appeal Br., p. 23). Atwood states that its claimed invention is a gas
sensor.
Atwood argues that:
The fuel cell citations [Grot and Uchida] are not analogous to the
>648 Patent because they are neither in the field of ambient
atmosphere gas sensors nor reasonably pertinent to the problem
addressed by the >648 Patent, are inoperative in an ambient

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atmosphere, and would be poisoned, for example, by CO.

(Id. at 24).

The analogous-art test articulated in Graham requires that:
[A] reference is either in the field of the applicant's endeavor or is
reasonably pertinent to the problem with which the inventor was
concerned in order to rely on that reference as a basis for rejection.

In re Kahn, 441 F.3d 977, 987, 78 USPQ2d 1329, 1335-36 (Fed. Cir. 2006.
Atwood identifies the field of its endeavor as electrochemical gas sensors.
Both Grot and Uchida are references in the field of electrochemical gas sensors.
Grot states that its electrodes may be used in Agas dosimeters and sensing devices
and the like.@ (Grot, col. 1, ll. 19-30). Similarly, Uchida states that its electrodes
may be used in Avarious gas sensors such as oxygen sensors and alcohol sensors.@
(Uchida, col. 10, lines 60-64).
At oral argument counsel for Atwood suggested that the particular gas
sensor statements in Grot and Uchida do not reflect the true nature of the
references. We
do not agree. Grot has three independent claims, claims 1, 11 and 12. While Grot
independent claim 11 is directed towards a fuel cell, independent claims 1 and 12
are directed to electrodes and do not recite an intended use. Similarly, Uchida
claims 19 and 20 are directed towards a Asolid polymer electrolyte membrane and
electrode assembly@ and make no mention of an intended use. Accordingly,
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consistent with statements in their specifications, the claims of Grot and Uchida
demonstrate that Grot and Uchida did not intend their electrodes to be limited to
the field of fuel cells.
Additionally, the problem faced by Atwood=s inventors was finding a
suitable

membrane and electrode structure for detection of oxidation and reduction
reactions via the generation of electrical current. Atwood does not dispute that
Grot and Uchida teach electrodes that are suitable for use in oxidation and
reduction
reactions that generate electrical currents. (See, e.g., Uchida at col. 4, lines 27-36).
Further, Dempsey itself recognizes that fuel cell electrodes may be employed in
gas sensors. Specifically, Dempsey identifies two Afuel cell@ references3 as
describing electrodes that may be used in Dempsey=s gas sensor. (Dempsey, col.
7, lines 31-49).
Atwood=s fuel cell arguments have been considered but we find that
Atwood has failed to demonstrate that one of ordinary skill in the art would
understand that the teachings of Grot and Uchida are limited to fuel cells.
Specifically, as stated
above, Grot and Uchida explicitly teach that their electrodes may be used in gas

3U.S. Patent 3,134,697, entitled AFuel Cell@ and U.S. Patent 3,297,484, entitled AElectrode
Structure and Fuel Cell Incorporating the Same.@
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sensors. Further, the electrodes claimed by Grot and Uchida are not limited to a
particular use. Also, Dempsey teaches that, at a minimum, there is overlap
between Afuel cell@ electrodes and electrodes that may be used in gas sensors. We
find that Grot and Uchida, like Dempsey, are within the field of Atwood’s gas
sensor endeavor. We further find that Grot and Uchida are reasonably pertinent to
the problem addressed by Atwood, selecting an appropriate electrode that
generates electrical current in the presence of oxidation/reduction reactions. We
find that one of ordinary skill in the art would understand that Grot and Uchida
represent

analogous art as Grot and Uchida are references within the field of electrochemical
gas sensors and are reasonably pertinent to Atwood’s endeavor to select an
appropriate electrode for its gas sensor.
Similarly, Vanderborgh explicitly teaches that its electrodes are not limited
to fuel cells and may be utilized in applications that involve electrochemical
generation of electrical power from the consumption of reacting gases or liquids.
(Vanderborgh, col. 11, ll. 20-38). Indeed, Atwood dependent claim 12 is directed
towards the detection of water vapor and Vanderborgh states that its invention is
applicable to systems wherein water in the vapor state is electrolyzed to generate
hydrogen and oxygen. (Id., col. 11, ll. 26-29). We find that Vanderborgh, like
Grot and Uchida, is reasonably pertinent to the problem address by Atwood, the
selection of an appropriate electrode that generates electrical current in the
presence of oxidation/reduction reactions. We further find that Vanderborgh is a
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reference that
is reasonably pertinent to Atwood’s field of endeavor of detecting gases where
electrical current is generated by the oxidation/reduction of the gas to be detected.

ii. Reasons for Combining the References
Atwood argues that the Examiner has failed to establish that one of ordinary
skill in the art would have been motivated to combine the teachings of Dempsey
with Grot, Uchida or Vanderborgh and make Atwood=s claimed gas sensor.
(Appeal Br., pages 34-39). In particular, Atwood alleges that the motivation to
combine the references is not apparent and the Office has failed to explain the

motivation with objective evidence. (Id. at 35). Atwood also argues that Grot and
Uchida recite numerous possible applications for their membrane and electrode
structures and that this broad description does not teach or suggest an ambient
atmosphere application. (Reply Brief, p. 6).
The Examiner=s Final Office Action (Paper 12) states that Dempsey teaches
Atwood=s claimed gas sensor with the exception of the claimed electrodes having
both ionically and electrically conductive materials. (Paper 12, p. 4). The
Examiner cites Grot, Uchida and Vanderborgh as describing the claimed
electrodes. The Examiner states that the electrodes of Grot, Uchida and
Vanderborgh would provide improved electrical properties to Dempsey=s gas
sensor. (Id.). Further, the Examiner states that the substitution of one known
electrode for another requires only routine skill in the art. There is objective
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evidence of record to support the Examiner=s position.
Dempsey states that suitable electrodes for Dempsey=s gas sensor are
described in U.S. Patents 3,432,355, 3,134,697 and 3,297,484. (Dempsey, col. 8,
ll. 31-49). As acknowledged by Atwood, the ‘355, ‘697 and ‘484 references
describe the use of electrodes in fuel cell. (Appeal Br., p. 21). Dempsey thus
informs one of ordinary skill in the art that, at a minimum, there is overlap between
electrodes employed in fuel cells and in gas sensors.
Grot provides a statement identifying the background of Grot=s invention.
In this section, Grot teaches that one of ordinary skill in the art knows that
membrane and electrode cells are suitable for use in fuel cells and gas sensing
devices. (Grot,

col. 1, ll. 19-30). Grot specifically identifies and discusses the >484 and >697
patents, both of which were identified by Dempsey as describing suitable
electrodes for Dempsey=s gas sensor. (Grot, col. 1, line 40 to col. 2, line 14). Grot
teaches that
prior electrode techniques, including those described in the >484 and >697 patents,
were inefficient, had poor reproducibility and required large loading of catalyst to
form an acceptable electrode. (Id. at col. 3, ll. 4-15). Grot teaches that, in contrast
to prior art electrodes, Grot=s electrodes have excellent characteristics, including a
uniform electrode structure and a reduced risk of delamination. (Id. at col. 3, line
60 to col. 4, line 29). Grot exemplifies electrodes having Aelectron conductive
mixed material and proton conducting material.@ Specifically, Grot teaches the
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formation of an electrode from NAFION7 and a catalyst having 20% platinum on a
VULCAN7 carbon support.4 (Id. at col. 14, ll. 15-27).

4Atwood=s >054 patent under reexamination identifies NAFION7 as a suitable
proton conductor material, and platinum on Avulcan carbon@ as a suitable proton-
electron mixed material. (>054, col. 14, Table and ll. 37-56).
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Grot=s statement of improved electrode structure represents objective
evidence that one of ordinary skill in the art was aware that Grot=s mixed proton-
electron electrodes represented an improvement over the electrodes described by
Dempsey. We find that one of ordinary skill in the art reading Grot and Dempsey
would have been motivated to employ Grot=s proton-electron mixed conductive
electrodes in Dempsey=s gas sensors as Grot specifically teaches that Grot=s
electrodes provide improved electrical characteristics compared to those described
in Dempsey.
Uchida, like Grot and Dempsey, describes electrodes that generate electrical
current in the presence of oxidation/reduction reactions. Uchida, like Dempsey
and Grot, describes its electrodes as useful in fuel cells and in gas sensors. We
conclude that it is prima facie obvious to combine the known gas sensing
components of Uchida and Dempsey for their known ability to detect gases and
form a gas sensor, i.e., it is obvious to combine known components for their known
purpose to form an article having that purpose. Cf., In re Kerkhoven, 626 F.2d
846, 850, 205 USPQ 1069, 1072 (CCPA 1980) (AIt is prima facie obvious to
combine two compositions each of which is taught by the prior art to be useful for
the same purpose, in order to form a third composition which is to be used for the
very same purpose.@).
Vanderborgh, like Grot and Uchida, describes electrodes that generate
electrical current in the presence of oxidation/reduction reactions. Vanderborgh
also describes its electrodes as useful electrochemical devices that produce

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electrical power from the consumption of reacting gases, for example,
electrolyzing water vapor to hydrogen and oxygen. Vanderborgh states that its
electrodes represent an improvement over the prior art. For example,
Vanderborgh’s electrodes minimize the amounts of electrocatalyst necessary to
achieve the highest value of water per mg of electrocatalyst. We conclude that it is
prima facie obvious to employ the known electrodes of Vanderborgh in the gas
sensor of Dempsey as Vanderborgh teaches that its electrodes may be employed in
devices involving the generation of electrical current due to the consumption of
reacting gases and as Vanderborgh teaches that its electrodes represent an
improvement over the prior art.
We conclude that one of ordinary skill in the art presented with Dempsey
and Grot, Uchida and/or Vanderborgh would have been motivated to use the
proton-electron mixed conductive electrodes described in Grot, Uchida and
Vanderborgh in Dempsey=s gas sensor.
Additionally, we conclude that one of ordinary skill in the art would be
motivated to construct Dempsey’s gas sensor having the claimed electrode
diameter as Dempsey teaches that counter and sensing electrodes having a diameter
of 16
mm are suitable for use in a compact electrochemical gas sensing cell for detecting
gases. Alternatively, we find that one of ordinary skill in the art would know that
the size of the sensing and counter electrodes are result effective variables for
electrochemical gas sensors as the size of the electrode will affect the amount of
current flow and sensitivity of the sensor. (See, e.g., Dempsey, col. 6, ll. 20-37).
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As the optimization of a result effective variable for a known device is within the

skill of the art, we also conclude that the Examiner has established that it was
prima facie obvious to discover the optimum diameter for the sensing and counter
electrodes.

iii. Reasonable Expectation of Success
Atwood contends that there is no reasonable expectation of success to arrive
at Atwood=s claimed subject matter. Specifically, Atwood argues that:
When considering each of claims 1, 3-6, 8-17, 75, 79 and 80 of the
>648 Patent as a whole, rather than considering only the differences
between the claims and the citations, the citations do not provide
sufficient guidance such that one skilled in the art would have any
reasonable expectation of success in arriving at Appellant=s claimed
subject matter. Therefore, each of claims 1, 3-6, 8-17, 75, 79 and 80
of the >648 Patent is patentable over the citations.

(Appeal Br. at p. 40).
Atwood=s argument is not supported by the record. Dempsey, Grot, Uchida
and Vanderborgh all describe membrane and electrode structures that generate
electricity in the presence of oxidation/reduction reactions. Dempsey, Grot, and
Uchida all describe their electrodes as suitable for use in gas sensors, as well as
fuel cells. Further, Grot goes so far as to teach that its proton-electron mixed
conductive electrodes are superior to electrodes described and employed by
Dempsey. Similarly, Vanderborgh explicitly states that its electrodes may be
employed in devices that generate electrical current based upon the consumption of
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reacting gases and states that its electrodes provide improved properties. Thus, one
of

ordinary skill in the art would have had a reasonable expectation that the proton-
electron mixed conductive electrodes of Grot, Uchida and Vanderborgh would
generate electricity in the presence of the oxidation/reduction reactions employed
in Dempsey=s gas sensor. Based upon the record presented, we do not credit
Atwood=s attorney argument to the contrary. Rohm & Haas Co. v. Brotech Corp.,
127 F.3d 1089, 1092, 44 USPQ2d 1459, 1462 (Fed. Cir. 1997)(Nothing in the rules
or in jurisprudence requires trier of fact to credit unsupported or conclusory
assertions).

iv. Dempsey in Combination with Grot, Uchida and/or
Vanderborgh Teach or Suggest Every Claimed Element

Atwood argues that Grot, Uchida and Vanderborgh teach away from
Atwood=s claimed subject matter. According to Atwood, Grot and Uchida
describe fuel cells that do not operate under ambient conditions.5 Atwood also
argues that

5We note that Atwood fails to provide a specific definition of the term ambient that
would exclude the fuel cell temperature and pressure conditions identified in Grot
and Uchida. As Grot and Uchida explicitly describe their electrodes as suitable for
use in gas sensor applications, we need not determine whether Grot and Uchida=s
fuel cells employ ambient conditions.
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Vanderborgh’s electrodes are too small. Atwood concludes that each of the
references Aleads away from the subject matter of the claims@ and that the
references are not combinable to form a device having each and every element of
the appealed claims (Appeal Br. at 42).
A reference may be relied upon for all that it teaches and not merely its
preferred embodiments. Grot and Uchida describe their proton-electron mixed
conductive electrodes as being used in a variety of applications, including gas
sensors as well as fuel cells. Grot and Uchida=s claimed electrodes are not
restricted in their use. That Grot and Uchida=s fuel cells may employ non
Aambient@ temperature and pressure conditions does not negate the fact that both
Grot and Uchida specifically state that their electrodes have utility in gas sensor
applications. Taking the teachings of Grot and Uchida as a whole, we find that
Grot and Uchida do not Ateach away@ from Atwood=s claimed subject matter.
Atwood is correct in stating that Vanderborgh describes an electrode that has
a smaller diameter than that recited in Atwood’s claims. Atwood however, fails to
demonstrate that Vanderborgh is limited to such diameters. For example, while all
of Vanderborgh’s claims are directed to electrodes, none of Vanderborgh’s claims
is limited to a particular diameter.
Taking Grot, Uchida and Vanderborgh as a whole, we find that the
references do not teach away from Atwood’s claimed gas sensor. We conclude
that Dempsey taken in combination with Grot, Uchida and/or Vanderborgh teach
all that is required by Atwood claim 1.
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v. Atwood=s Alleged Commercial Success Lacks Nexus to
Claimed Invention

Atwood has submitted a Declaration of Corry Cochran (Paper 14), the
controller for the Salt Lake City operations of Atwood Industries. Atwood alleges
that Cochran=s declaration provides evidence of commercial success and is an
indicator of the nonobviousness of its claimed invention. (Appeal Br., p. 58).
For commercial success to be relevant on the issue of obviousness there
must be a nexus between the sales of the product and the merits of the claimed
invention. Nexus may be inferred when Athe patentee shows both that there is
commercial success, and that the thing (product or method) that is commercially
successful is the invention disclosed and claimed in the patent.@ Demaco Corp. v.
F. Von Langsdorff Licensing Ltd., 851 F.2d 1387, 1392, 7 USPQ2d 1222, 1226
(Fed. Cir. 1988). Yet, Aif the commercial success is due to an unclaimed feature of
the device, the commercial success is irrelevant.@ Ormco Corp. v. Align
Technology Inc., 463 F.3d 1299, 1312, 79 USPQ2d 1931, 1941 (Fed. Cir. 2006)
Cochran=s declaration states that he is responsible for preparing, reviewing
and analyzing Atwood=s financial statements, cost accounting and general
accounting. (Cochran Dec., & 1). Cochran testifies that:

The >648 Patent and the >054 Patent are the subject of a royalty-
bearing license agreement. My duties outlined in paragraph 1 above
include receiving and monitoring periodic royalty reports and periodic
royalty payments under such license agreement. Such periodic
royalty reports include a statement of the volume of carbon monoxide
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sensors sold

under the license agreement (APatented CO Sensors@).

(Id. at & 4). Mr. Cochran states that from 1999 to 2001 there was a 26.7% increase
in sales of the licensed CO Sensors. (Id. at & 8).
Mr. Cochran=s declaration fails to identify the structural features of the
commercially available gas sensor sold under the license. Specifically, beyond the
licensed sensors ability to detect carbon monoxide, little is known about the
specific materials used to form the sensor and how the sensor operates.
Accordingly, we are unable to determine whether the commercially available gas
sensors are commensurate in scope with those claimed by Atwood.
Mr. Cochran=s declaration fails to demonstrate that the increase in sales of
the licensed CO sensors resulted from unique characteristics of the claimed
invention as opposed to other economic and commercial factors unrelated to the
technical nature of the claimed subject matter. Mr. Cochran=s declaration is
accorded little, if any, weight on the issue of obviousness.
At oral argument, counsel for Atwood argued that the licensed product

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represented an advance due to the portability, accuracy and reliability of the
licensed CO sensor. Counsel stated that the success of the product was due in part
to this advancement over the prior art. Yet, the features identified by Atwood=s
counsel, portability, reliability and accuracy, are not explicitly or implicitly
required by the claims on appeal. We find that Atwood has failed to establish that
the success of the licensed product was due to the novel features present in all the
appealed claims, i.e., use of proton-electron mixed conductive material electrodes
in a gas sensor.

vi. Alleged Advantages over the Prior Art are not Supported by
Credible Evidence

Atwood=s Reply Brief states that by using the sensors of the present
invention, Abattery life can be greatly prolonged, an advantage that the Dempsey et
al. sensor cannot achieve.@ (Reply Brief, p. 9). Atwood requests that this
secondary consideration be properly considered. (Id.).
Atwood=s attorney argument as to potential advantages that may be
achieved by the claimed subject matter is not supported by credible evidence.
Specifically, we do not credit Atwood=s attorney argument as establishing that the
claimed subject matter possesses unexpected properties or results as compared to
the prior art. Rohm & Haas Co. v. Brotech Corp., 127 F.3d 1089, 1092, 44
USPQ2d 1459, 1462 (Fed. Cir. 1997)(Nothing in the rules or in jurisprudence
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requires trier of fact to credit unsupported or conclusory assertions).

vii. Claim 1 is Obvious over Dempsey taken in combination with
Grot and/or Uchida

We conclude that Atwood claim 1 is obvious over Dempsey taken in
combination with Grot, Uchida and/or Vanderborgh. We draw this conclusion
based upon the findings of fact identified above and summarized below.
Dempsey teaches all limitations of Atwood claim 1 with the exception of the
proton-electron mixed conductive electrodes. Grot, Uchida and Vanderborgh
describe proton-electron mixed conductive electrodes.
Dempsey, Grot, Uchida and Vanderborgh are analogous art in the field of
gas sensors. Grot and Uchida, like Dempsey, specifically identify their membrane
and electrode structures as having application in both the field of gas sensors as
well as fuel cells. Grot and Uchida, like Dempsey, teach that their membrane and
electrode structures generate electrical current in the presence of
oxidation/reduction reactions. Additionally, Grot teaches that its proton-electron
mixed conductive electrodes represent an improvement over the electrodes
employed by Dempsey. Similarly, Vanderborgh teaches that its electrodes provide
improved properties and can be used in devices that require electrochemical
generation of electrical power from reacting gases.
One of ordinary skill in the art would have found it prima facie obvious to
form Atwood=s claimed gas sensor given Dempsey in view of Grot, Uchida and/or
Vanderborgh as it is obvious to combine known components for their known
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purpose to form an article having that purpose, i.e., using a known gas sensor

proton-electron mixed conductive electrode that generates electrical current in the
presence of oxidation/reduction reactions in a known gas sensor that detects gases
via oxidation/reduction reactions is prima facie obvious. This is especially true
where the prior art identifies the known proton-electron mixed conductive
electrodes as having improved characteristics. Additionally, we have evaluated
Atwood=s evidence of commercial success but find that it fails to demonstrate that
the alleged success is due to a claimed and unique feature of the gas sensor.
Atwood=s arguments concerning claims 3-6, 8, 9, 13-16, 75, 79 and 80 are
addressed below.

viii. Dempsey taken in light of Grot and/or Uchida renders obvious
clams 3-6, 8, 9, 13-16, 75, 79 and 80

We affirm the Examiner’s prior art rejection of Atwood claims 3-6, 8, 9, 13-
16, 75, 79 and 80.

Claims 3-5 and 14-16
Atwood claim 3-5 depend from claim 1 and further require that the sensing
and counter electrodes comprise carbon, noble metals and conductive metal oxides.
Atwood claims 14 depends from claim 1 and requires that the electrodes comprise
10-50 wt% of a proton conductor material and 50-90 wt% of a first and second
conductor material. Atwood claim 15 depends from claim 14 and requires that the
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proton conductor be a copolymer having a tetrafluoroethylene backbone with a
side

chain of perfluorinated monomers containing at least one sulfonic acid group.
Atwood claim 16 depends from claim 14 and requires that one of the first and
second conductor materials is 50-99 wt% carbon black and the other is 1-50 wt%
platinum. Atwood states that no combination of references discloses the claimed
gas sensor having such electrodes. (Appeal Br., p. 44-45 and 50-51).
As discussed above, Grot teaches the formation of an electrode from
NAFION7 and a catalyst having 20% platinum on a VULCAN7 carbon support.
(Grot, col. 14, ll. 15-27). Grot also teaches that electrodes may be formed from
electroconductive oxides. (Grot, col. 4, ll. 56-61). Similarly, Uchida teaches that
its electrodes contain at least a noble metal catalyst, a carbon powder and a solid
polymer electrolyte. (Uchida, col. 3, lines 46-56). Also, Vanderborgh describes
forming its electrodes with a mixture of platinum or any other suitable
electrocatalyst dispersed and supported on carbon black and further describes
NAFION7 as a suitable binder for electrodes. (Vanderborgh, col. 3, ll. 11-14 and
col. 8, ll. 13-25).
One of ordinary skill in the art would have been motivated to form sensing
and counter electrodes with carbon black and noble metals or metal oxides as
Dempsey describes electrodes formed from noble metals and as Grot, Uchida and
Vanderborgh teach that suitable electrodes for gas sensing applications may be
formed with carbon and any suitable electroconductive material, such as noble
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metals or metal oxides. Additionally, one of ordinary skill in the art would have
been motivated to form electrodes having the claimed percentages of carbon black

and platinum with a tetrafluoroethylene copolymer as Grot, Uchida and
Vanderborgh all teach that such electrodes are known in the art to generate
electrical current in the presence of gaseous reactions and as Grot and Uchida
explicitly identify their electrodes as suitable for use in gas sensing applications.

Claim 6
Atwood claim 6 depends from claim 1 and further requires that the gas
sensor membrane be composed of a solid, perfluorinated ion-exchange polymer.
(Appeal Br., p. 68, claim 6). Atwood argues that no combination of the cited
references teaches or suggests the gas sensor of claim 6.
Atwood=s argument is not well understood. Dempsey specifically states
that perfluorocarbon sulfonic acid membranes are the preferred solid polymer
electrolyte ion-exchange membrane material. (Dempsey, col. 6, ll. 45-62).
Dempsey states that the perfluorocarbon sulfonic acid membranes provide
excellent ion exchange capacity, are highly stable, and have excellent thermal
stability. (Id.). Dempsey’s preferred perfluorocarbon membrane is a hydrated
copolymer of
polytetrafluoroethylene (PTFE) and polysulfonyl fluoride vinyl ether containing
pendant sulfonic acid groups sold under the NAFION trade designation. (Id. at
col. 6, line 66 to col. 7, line 16).
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Atwood=s >054 patent states that its protonic membrane is preferably
formed from NAFION 117 and identifies this material as a tetrafluoroethylene
copolymer. (A054, col. 8, ll. 35-49). Similarly, Uchida teaches that NAFION 117
forms an

effective solid polymer electrolyte membrane. (Uchida, col. 8, ll. 11-17).
Similarly, Grot teaches that its membrane may be formed from a commercial
perfluorocarbon membrane sold under the NAFION trade designation. Likewise,
Vanderborgh describes NAFION as a suitable binder for its electrodes.
Accordingly, we find that Grot, Uchida and Vanderborgh describe the use of
perfluorinated, ion-exchange polymer membranes.
We conclude that one of ordinary skill in the art would have been motivated
to form a perfluorinated, ion-exchange polymer membrane in light of Dempsey=s
teaching that such a membrane is preferred for a gas sensor due to its stability and
excellent ion exchange capacity. Further, Grot, Uchida and Vanderborgh likewise
direct one of ordinary skill in the art to employ such membranes.

Claims 8 and 79
Atwood claims 8 and 9 depend from claim 1 and require that the gas sensor
be adapted to detect carbon monoxide and nitrogen oxides. Claim 79 is an
independent claim and differs from claim 1 in that it explicitly states that carbon
monoxide is the gas being measured. Atwood argues that no combination of
references discloses, teaches or suggests the claimed gas sensor adapted to detect
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carbon monoxide. (Appeal Br., p. 46)
Dempsey teaches that its gas sensor detects gases Asuch as carbon
monoxide, NO2, alcohol vapors, etc.@ (Dempsey, abstract). Dempsey teaches that
a gas stream containing the Aconstituents to be detected is brought into contact
with the sensing

electrode.@ (Id. at col. 4, ll. 54-60). Dempsey further teaches that:
Changes at the sensing electrode due to the oxidation of carbon
monoxide or any other gas causes a change in the relative potential
between the sensing and reference electrode.

(Id. at col. 9, ll. 24-27).
Atwood argues that the Examiner has failed to appreciate that the sensing of
different gases requires different formulations of materials used to construct the
sensing and counter electrodes. Atwood states that one skilled in the art, knowing
the gas to be sensed, could readily select the appropriate materials in light of the
knowledge provided by Atwood=s specification. (Appeal Br., p. 48).
Atwood fails to specifically state how its specification teaches one of
ordinary skill in the art how to select the appropriate materials. Further, Atwood=s
specification provides the following statement regarding the selection of materials
for detecting gases such as hydrogen and H2S:
While the inventive gas sensor can be used to measure CO
concentration, it is also capable of measuring other gases such as H2,
H2S, H2O vapor alcohol, and NOx concentrations.

(>648 patent, col. 11, ll. 63-65).
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Dempsey teaches that its sensor, like Atwood=s, detects gases that bring
about a change in potential between the sensing and reference electrode. Dempsey,
like Atwood, states that its sensor detects a variety of gases including carbon
monoxide, NOx and alcohol vapors. Dempsey’s specification, like Atwood’s,
provides little if any guidance as to the selection of the materials needed to detect a
specific gas.

Additionally, we note that Tomantschger teaches that one of ordinary skill in the
art knew how to devise a specific gas detection system using suitable catalysts and
electrolytes to test for any toxic, combustible or flammable gas. (Tomantschger,
col. 2, ll. 42-46). Based upon the references of record, including Dempsey and
Tomantschger, we find that one of ordinary skill in the art knew how to select the
appropriate materials to detect a particular gas. 6

6 See, In re Epstein, 32 F.3d 1559, 1568, 31 USPQ2d 1817, 1823 (Fed. Cir. 1994)
("Rather, the Board's observation that appellant did not provide the type of detail in
his specification that he now argues is necessary in prior art references supports the
Board's finding that one skilled in the art would have known how to implement the
features of the references and would have concluded that the reference disclosures
would have been enabling."); In re Fox, 471 F.2d 1405, 1407, 176 USPQ 340, 341
(CCPA 1973) (appellant's specification "assumes anyone desiring to carry out the
process would know of the equipment and techniques to be used, none being
specifically described"); Constant v. Advanced Micro-Devices, Inc., 848 F.2d
1560, 1569, 7 USPQ2d 1057, 1063 (Fed. Cir. 1988) ("The disclosure in Exhibit 5
is at least of the same level of technical detail as the disclosure in the '491 patent.
If disclosure of a computer program is essential for an anticipating reference, then
the disclosure in the '491 patent would fail to satisfy the enablement requirement of
35 U.S.C. ' 112, First &.").
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Claim 13
Atwood claim 13 depends from claim 1 and requires that the diameter of the
sensing and counter electrodes be about 10 mm and that the protonic conductive
electrolyte membrane have a thickness of about 0.17 mm.
As to the dimensions of the membrane, the Examiner states that it would

have been obvious to utilize a membrane having the particular size as Dempsey
teaches a membrane having a size of 0.3 mm and one skilled in the art would
recognize that a thinner membrane provides for reduced internal resistance.
Atwood disagrees with the Examiner that finding the optimal membrane thickness
requires only routine skill in the art. According to Atwood, Dempsey fails to
provide an explanation of the “numerous considerations” that would have to be
taken into account to optimize the membrane thickness.
Dempsey teaches that the purpose of the membrane is to separate the sensing
and counter electrodes and allow for the passage of positively charged ions while
rejecting the passage of negatively charged ions. (Dempsey, col. 6, ll. 45-51).
While Atwood claims a membrane thickness of 0.17 mm, Dempsey Example 4
employs describes a cell membrane formed from 0.3 mm thick NAFION ®. Grot
however, teaches that its electrodes provide superior properties as compared to
those described in Dempsey. Grot further teaches that the thickness of the
membrane typically ranges from 25 to 175 microns, i.e., .025 to .175 mm, a range
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that encompasses Atwood’s claimed .17 mm. (Grot, col. 12, ll. 38-39).7
The Federal Circuit has provided the following guidance regarding a prior
art range that encompasses a claimed range:
We therefore conclude that a prior art reference that discloses a range
encompassing a somewhat narrower claimed range is sufficient to establish a

prima facie case of obviousness. That is not to say that the claimed
composition having a narrower range is unpatentable. Rather, the existence
of overlapping or encompassing ranges shifts the burden to the applicant to
show that his invention would not have been obvious, as we discuss below.

In re Peterson, 315 F.3d 1325, 1331, 65 USPQ2d 1379, 1383-84 (Fed. Cir. 2003).
The claimed dimensions are encompassed by the prior art teachings, i.e.,
0.17 mm falls within the range of 0.025 to 0.175 mm. Based upon the evidence of
record, we conclude that the prior arts disclosure of a membrane range
encompassing Atwood’s claimed membrane dimensions is sufficient to establish a
prima facie case of obviousness as to the membrane size.
As to the dimensions of the electrodes, Dempsey exemplifies an electrode
having 16 mm as opposed to Atwood’s claimed 10 mm. (Dempsey, Example 4,
col. 11, ll. 65-67). The Examiner states that one of ordinary skill in the art would
use smaller electrodes in Dempsey in order to make for a more compact design so
as to reduce costs associated with the noble metals, e.g., platinum, that are
employed in the electrodes. (Answer, p. 6). Atwood disagrees.

7 Note, Vanderborgh teaches that typical ion exchange membranes in fuel cells
have a thickness of 0.002 to 0.012 inches, i.e., 0.05 mm to 0.3 mm. (Id. at col. 2,
ll. 51-56).
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Atwood argues that there are “invariably multiple manufacturing and
product performance concerns leading to any particular product design.” (Appeal
Br., p. 49). Atwood states that Dempsey does not address the “trade offs between
cost and performance, manufacturing, durability, etc. .. with respect to the size
and/or materials used to make the electrodes having only electronic conductors.”
(Id.).
Grot teaches that one of ordinary skill in the art was aware that prior art
electrodes suffered from problems such as the need for “substantial quantities of

expensive catalyst materials to prepare membrane and electrode structures.” (Grot,
col. 3, ll. 4-11). Grot teaches the benefits of forming electrodes having a relatively
small loading of catalyst in an efficient, inexpensive and reproducible manner. (Id.
at col. 3, ll. 49-57).
We conclude that Atwood has failed to demonstrate that the Examiner erred
in concluding that the electrode dimensions would have been obvious to one of
ordinary skill in the art. Specifically, Dempsey exemplifies counter and sensing
electrodes that are larger than those claimed by Atwood, however, Grot provides
objective evidence that one skilled in the art was aware of the need to reduce the
amount of expensive catalyst used in forming the electrodes. We find that one of
ordinary skill in the art, following the teachings of Grot, would have been
motivated to use smaller diameters than that exemplified by Dempsey.
Additionally, Atwood acknowledges that the electrode dimensions will have
an effect upon the performance and durability of the electrodes. (Id. at 49). It is
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well recognized that the “discovery of an optimum value of a result effective
variable in a known process is ordinarily within the skill in the art.” In re Boesch,
617 F.2d 272, 276, 205 USPQ 215, 219 (CCPA 1980). Specifically, where the
general conditions of the claims are disclosed in the prior art, it is not inventive to
discover the optimum or workable ranges by routine experimentation. In re Aller,
220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). In the present case,
Dempsey exemplifies the use of a larger diameter than claimed by Atwood, yet
Grot expressly teaches one of ordinary skill in the art to reduce the amount of
catalyst

used in forming an electrode. One of ordinary skill in the art would recognize that
a
smaller diameter electrode, having Grot’s desired uniform structure, would allow
for a reduction in the total amount of catalyst used. Thus, in addition to the
motivation discussed above, we also conclude that the one of ordinary skill in the
art desiring the reduction in amount of catalyst used in the electrodes would
conduct routine experimentation to achieve the desired dimensions, which are
acknowledged to be result effective variables.
Atwood does not allege any improved performance or unexpected benefit
arising from the claimed membrane or electrode dimensions. Based upon the
evidence presented, we conclude that the Examiner did not err in rejecting Atwood
claim 13 as obvious over the prior art.

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Claim 75
Atwood claim 75 depends from claim 1 and requires that the sensing and
counter electrodes have a first side opposite a second side and that the ionic and
conducting materials are continuous from the first to second side.
The Examiner relies upon Vanderborgh as demonstrating that it was known
in the art to form homogeneous electrodes. Specifically, Vanderborgh teaches that
it was known in the art to form electrodes comprising a homogeneous mixture of
an ion exchange polymer, an electrical conductor and an electrocatalyst.
(Vanderborgh, col. 3, ll. 7-11).
Atwood contends that none of the prior art references teaches or suggests

forming sensing and counter electrodes having an ionically conducting material
and
electronically conducting material that is continuous from a first side to a second
side. (Appeal Br., p. 53).
The prior art teaches the use of uniform, homogeneous electrodes.
Specifically, in addition to Vanderborgh, Grot describes the formation of a uniform
electrode structure that uses a relatively small loading of catalyst. (Grot, col. 3, ll.
49-57). Grot teaches that such electrodes have excellent characteristics and are
superior to those of the prior art. (Id. at col. 3, ll. 4-15 and ll. 60-62). One of
ordinary skill in the art would have been motivated to employ the known uniform
“continuous” electrode structures of the prior art in the gas sensor of Dempsey as
such electrodes provide excellent characteristics including a reduction in the
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amount of expensive catalyst, while not adversely decreasing the ionic
conductivity of the structure.

Claim 80
Atwood claim 80 depends from independent claim 79 and further requires
that the gas sensor have a cap in communication with the sensing electrode.
Atwood’s specification describes the term “can” in conjunction with the use of a
cap and can design gas sensor. (‘648, e.g., col. 6, ll. 1-3).
The Examiner relies upon Dempsey as teaching a cap. In particular, the
Examiner states that bottom plate 15 of Dempsey Figure 1 is a cap as the term is
broadly construed. Atwood disagrees. Atwood argues that:

Such bottom plate is not the cap recited in claim 80. In particular, the
cap recited in claim 80, as taught in the specification of the ‘648
Patent
and as shown in the drawings, is for enclosing the sensing and counter
electrodes and is in communication with the sensing electrode.
Dempsey shows no such cap. Thus, Dempsey either alone or on [sic,
in] combination with any citation fails to render claim 80 obvious.

(Appeal Br. at 53-54).
Claims are given their broadest reasonable construction during prosecution
before the USPTO because claims may be amended to the proper scope and
because it serves the public interest by reducing the possibility that the claims will
be construed more broadly after issuance than they were during examination. In re
Bigio, 381 F.3d 1320, 1324, 72 USPQ2d 1209, 1211 (Fed. Cir. 2004). The plain
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language construction of the term “cap” is something that provides cover. Giving
the term “cap” its broadest reasonable construction, we construe the term cap as
encompassing a thing that provides cover.
Dempsey’s bottom plate covers the bottom of the sensing (13) and reference
(11) electrodes. As shown in Figure 1, the sensing electrode 13 is placed above the
chamber 14 and extends above Dempsey’s bottom plate covering 15. Accordingly,
we find that Dempsey’s bottom plate 15 is in contact with the sensing electrode.

We conclude that Dempsey’s bottom plate covering 15 is a cap that is in contact
with the sensing electrode.
For the reasons provided above, we affirm the Examiner’s rejection of
claims 1, 3-6, 8, 9, 13-16, 75, 79 and 80 under 35 U.S.C. 103(a) as being
unpatentable over Dempsey in view of Grot, Uchida and/or Vanderborgh.

C. Claim 7 is rejected under 35 U.S.C. § 103(a) as being unpatentable
over Dempsey in view of Grot, Uchida or Vanderborgh and further in
view of Tomantschger.

Atwood claim 7 depends from claim 1 and further requires that the
membrane be formed from a metal oxide protonic conductor electrolyte.
The Examiner acknowledges that Dempsey, Grot and Uchida fail to
Aexplicitly recite the use of a metal oxide protonic conductor electrolyte.@
(Examiner=s Answer, p. 6). The Examiner cites Tomantschger for the teaching of
a metal oxide membrane for use in a gas sensor. The Examiner concludes that it
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would have been obvious to one of ordinary skill in the art to form a gas sensor
having the membrane of Tomantschger. (Examiner=s Answer, p. 6). Atwood
disagrees.
Atwood argues that Tomantschger fails to disclose the use of a metal oxide
protonic conductive electrolyte membrane. (Appeal Br., p. 60). Atwood also
states that instead of a membrane, Tomantschger requires the presence of a third
frame member to retain electrolyte. (Id. at 60-61).

Dempsey, Grot and Uchida all teach the use of membrane and electrode
structures for use in gas sensing applications. Indeed, Grot identifies membrane
and electrode structures as well known in the art. (Grot, col. 1, ll. 29-30).
Similarly, Vanderborgh teaches the use of membrane and electrode structures for
devices that require electrochemical generation of electrical power from reacting
gases.
Dempsey employs a solid polymer electrolyte ion-exchange membrane
between its sensing and counter electrodes. As explained by Dempsey, its ion-
exchange membrane:
[P]ermits passage of positively charges ions, i.e., cations, and rejects
and blocks passage of negatively charged ions, anions.

(Dempsey, col. 6, ll. 48-51).
Tomantschger teaches a gas sensor cell for quantitative measurement of
volatile gas components. (Tomantschger, abstract). Specifically, Tomantschger
states that a specific cell system can be devised using suitable catalysts and
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electrolytes to test for any toxic, combustible or flammable gas. (Id. at col. 2, ll.
42-46).
Tomantschger’s gas sensor cell comprises a sensing electrode and a counter
electrode on either side of an ion conductive electrolyte. (Id. at abstract).
Tomantschger teaches that the sensor and electrolyte are chosen to produce a
change in electrical characteristic of the sensor electrode with respect to the
counter electrode in the presence of a gas to be measured. (Id. at col. 5, ll. 20-25).

Tomantschger states that the electrolyte may be a solid or polymer electrolyte. (Id.
at abstract). Tomantschger states that the electrolyte material may be an ionically
conductive solid material, such as uranyl hydrogenphosphate tetrahydrate. (Id. at
col. 8, ll. 34-38).
Atwood is correct in stating that Tomantschger describes the use of frame

members to hold its electrodes and electrolyte in place. Atwood however, fails to
explain how the use of frame members precludes Tomantschger=s solid ionically
conductive electrolyte from acting as a Amembrane.@
We find that one of ordinary skill in the art was familiar with membrane and
electrode structures. We further find that one of ordinary skill in the art understood
that the purpose of the membrane was to permit passage of positively charged ions
and block the passage of negatively charged ions such that an electrical change is
brought about between the sensing and counter electrodes. One of ordinary skill in
the art reading the cited references would have been motivated to use
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Tomantschger=s solid ionically conductive uranyl hydrogenphosphate tetrahydrate
electrolyte in a gas sensor, such as Demspey=s, because the electrolyte forms an
effective membrane for gas sensors employing a membrane and electrode structure.
We affirm the Examiner=s rejection of claim 7 as obvious over Dempsey in view
of Grot, Uchida and Vanderborgh and further in view of Tomantschger.

D. Claims 10 and 11 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Dempsey in view of Grot, Uchida or Vanderborgh
and further in view of LaConti.

Atwood claims 10 and 11 each depend from claim 1. Atwood claim 10
requires that the sensor be adapted to detect hydrogen and claim 11 requires the
sensor be adapted to detect hydrogen sulfide.
The Examiner states that Dempsey, Grot, Uchida, and Vanderborgh do not

explicitly identify hydrogen or hydrogen sulfide as the gases being detected.
(Examiner’s Answer, p. 7). The Examiner cites LaConti as teaching that it was
known in the art to adapt gas sensors to detect hydrogen and hydrogen sulfide.

(Id.).
Atwood states that there is no proper combination of references that teaches
or suggests each and every element of claims 10 and 11. Atwood argues that
LaConti teaches away from the subject matter of the claims as it requires that the
sensing and counter electrodes to be located on the same side of the membrane.
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Atwood concludes that one skilled in the art would not have been motivated to
adapt a gas sensor to detect hydrogen or hydrogen sulfide as LaConti, Dempsey,
Grot, Uchida and Vanderborgh describe different electrode arrangements. (Appeal
Br., p. 63).
As discussed above with respect to claims 8 and 79, Dempsey teaches that
its sensor, like Atwood=s, detects gases that bring about a change in potential
between the sensing and reference electrode. Dempsey, like Atwood, states that its
sensor detects a variety of gases including “carbon monoxide, NO2, alcohol vapors,
etc.” (Dempsey, Abstract).

LaConti confirms that one skilled in the art was well aware that hydrogen
and hydrogen sulfide could be detected using an electrochemical gas sensor. This
holds true even though LaConti describes a different placement for its sensing and

counter electrodes.
As discussed above, we find that one of ordinary skill in the art knew how to
select the appropriate gas sensor materials to detect a particular gas. We further
find that hydrogen and hydrogen sulfide are known gases that one skilled in the art
would attempt to detect. (See, e.g., LaConti, Table 1). Based upon the evidence of
record, we affirm the Examiner=s rejection of claims 9 and 10 as obvious over
Dempsey in view of Grot, Uchida and Vanderborgh and further in view of
LaConti.

E. Claim 12 is rejected under 35 U.S.C. § 103(a) as being unpatentable
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over Dempsey in view of Grot, Uchida or Vanderborgh and further in
view of Razaq.

Atwood claim 12 depends upon claim 1 and further requires that the sensor
be adapted to detect water vapor.
The Examiner states that Dempsey, Grot, Uchida, and Vanderborgh do not
explicitly identify water vapor as the gas being detected. (Examiner’s Answer, p.
7). The Examiner cites Razaq as teaching that it was known in the art to adapt gas
sensors to detect water vapor. (Id.).
Atwood’s arguments with respect to claim 12 are similar to those with
respect to claims 10 and 11 discussed above. Generally, Atwood argues that there
is no suggestion in Dempsey to use the electrodes of Grot, Uchida and/or
Vanderborgh and Razaq fails to cure this deficiency. (Appeal Br., p. 65).
Razaq describes a gas sensor that is utilized to detect moisture. (Razaq,
Abstract). We find that Razaq confirms that one skilled in the art was well aware

that water vapor can be detected using a gas sensor. Razaq also teaches that the
presence of water vapor in an integrated circuit fabrication process can severely
effect the yield and quality of the circuit. (Razaq, col. 1, ll. 39-42). We conclude
that one skilled in the art would be motivated to adapt a gas sensor to detect water
vapor.
For the reasons provided with respect to claims 8, 10, 11 and 79 above, we
again find that of one of ordinary skill in the art would know how to select the
appropriate gas sensor materials to detect a particular gas. We affirm the
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Examiner=s rejection of claim 12 as obvious over Dempsey in view of Grot,
Uchida and Vanderborgh and further in view of Razaq.
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V. Conclusion
We AFFIRM the Examiner's final rejection of claims 1, 3-16, 75, 79, and 80.

AFFIRMED

smt

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PETER D. MCDERMOTT
BANNER & WITCOFF LTD
28 STATE STREET – 28TH FLOOR
BOSTON, MA 02199

ROBERT B. MURRAY
ROTHWELL, FIGG, ERNST & MANBECK P.C.
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