Ex parte Gough et al.

Board of Patent Appeals and Interferences

Dec 10, 1998

07874697 (B.P.A.I. Dec. 10, 1998)

Application for patent filed April 28, 1992. According1
to the appellants, the application is a continuation-in-part
of Application 07/450,852, filed December 14, 1989, abandoned.
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1)
was not written for publication in a law journal and (2) is
not binding precedent of the Board.
Paper No. 18
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte DAVID A. GOUGH
and
JOSEPH Y. LUCISANO
__________
Appeal No. 96-0251
Application 07/874,6971
___________
ON BRIEF
___________
Before PAK, ELLIS and OWENS, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the examiner’s final rejection of
claims 1-14, which are all of the claims in the application.
Appeal No. 96-0251
Application 07/874,697
2
THE INVENTION
Appellants’ claimed invention is directed toward methods
for extending the service life of an implantable sensor having
a corrodible reference electrode, at least one noble metal
cathodic working electrode, and at least one noble metal
anodic counter electrode maintained at low impedance, by 1)
reversing the polarization of electrodes in a recited manner;
2) using multiple electrodes with only one of the electrodes
being operative at any time; 3) applying a continuous cathodic
current to the reference electrode; or 4) increasing the input
impedance at the reference electrode and shielding the
reference electrode. Claims 3, 7, 9 and 10 are illustrative
and are appended to this decision.
THE REFERENCES
Krebs 2,508,523 May 23,
1950
Perley 2,563,062 Aug. 7,
1951
Hersch 2,805,191 Sep. 3,
1957
Sabins 2,998,371 Aug. 29,
1961
Dahms 3,458,421 Jul. 29,
1969
Joseph Y. Lucisano et al., “In Vitro Stability of an Oxygen
Appeal No. 96-0251
Application 07/874,697
The rejections under 35 U.S.C. §§ 102(b) and 112 have2
been withdrawn (answer, page 12).
3
Sensor”, 59 Analytical Chemistry 736-39, March 1, 1987
(Lucisano).
THE REJECTIONS
The claims stand rejected under 35 U.S.C. § 103 as
follows: claims 10, 11/10, 12, 13, 14/10, 14/12 and 14/13 over
Lucisano alone or in view of Perley; claims 1, 2, 7, 8, 11/1,
11/2, 11/7, 11/8, 14/1, 14/2, 14/7 and 14/8 over Lucisano in
view of Hersch, Dahms or Sabins; claims 3-6 over Lucisano in
view of Sabins; claims 9, 11/9 and 14/9 over Lucisano in view
of Krebs.2
OPINION
We have carefully considered all of the arguments
advanced by appellants and the examiner and agree with the
examiner that the methods recited in appellants’ claims 1, 2-
8, 10, 11/1, 11/2, 11/7, 11/8, 11/10, 12, 13, 14/1, 14/2,
14/7, 14/8, 14/10, 14/12 and 14/13 would have been obvious to
one of ordinary skill in the art at the time of appellants’
invention over the applied prior art. Accordingly, we affirm
the aforementioned rejections of these claims. However, the
Appeal No. 96-0251
Application 07/874,697
4
rejection of claims 9, 11/9 and 14/9 is not sustained.
Appellants state that the claims stand or fall together
as to each rejection (brief, page 4). We therefore limit our
discussion to one claim to which each of the above four
rejections applies, i.e., respectively, claims 10, 7, 3 and 9.
See In re Ochiai, 71 F.3d 1565, 1566 n.2, 37 USPQ2d 1127, 1129
n.2 (Fed. Cir. 1995); 37 CFR § 1.192(c)(5)(1993).
Rejection of claims 10, 11/10, 12, 13, 14/10, 14/12 and
14/13 over Lucisano alone or in view of Perley
Lucisano discloses an implantable sensor which has a
corrodible, silver/silver chloride reference electrode, a
platinum cathodic working electrode and a noble metal anodic
counter electrode (page 737, last full paragraph). The
counter electrode is maintained at low impedance and the
reference electrode is maintained at very high impedance
(paragraph bridging pages 737-738). Lucisano teaches (page
739, last full paragraph in left column) that “[t]ransient
local capacitive currents as a result of inadequate shielding
of the leads [of the working and reference electrodes] may
also have played a role” in the transfer of silver from the
reference electrode to the working electrode. This teaching
Appeal No. 96-0251
Application 07/874,697
5
indicates that there was some shielding on the reference
electrode. For this reason and because the reference
electrode is at very high impedance, the method disclosed by
Lucisano necessarily has the characteristics of appellants’
claimed method which, according to appellants, causes the
service life of the sensor to be extended. Thus, we find that
Lucisano anticipates appellants’ claim 10. Since anticipation
is the epitome of obviousness, we affirm the rejection of
claim 10. See In re Skoner, 517 F.2d 947, 950, 186 USPQ 80,
83 (CCPA 1975); In re Pearson, 494 F.2d 1399, 1402, 181 USPQ
641, 644 (CCPA 1974).
Even if, by “inadequate shielding”, Lucisano means that
the electrodes were not shielded, appellants’ claimed
invention would have been prima facie obvious to one of
ordinary skill in the art because Lucisano would have
indicated to such a person that shielding of the electrodes is
desirable to reduce transient local capacitive currents which,
Lucisano indicates, tends to cause transfer of silver from the
reference electrode to the working electrode (page 739, last
full paragraph in left column). One of ordinary skill in the
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Application 07/874,697
6
art, given this disclosure, would have been motivated to
shield the electrodes to the extent needed to reduce the
transfer of silver to the working electrode. Although
Lucisano states that “increasing the impedance and improving
the shielding may not alone lead to a lower rate of [silver]
deposition” (page 739, right column, lines 6-7), the
reference, when read as a whole including the teaching
discussed above, would have provided one of ordinary skill in
the art with a reasonable expectation that shielding the
electrodes would reduce the transfer of silver from the
reference electrode to the working electrode and thereby
extend the service life of the sensor. Because one of
ordinary skill in the art would have had both a motivation to
shield the electrodes and a reasonable expectation of success
in doing so, the method recited in appellants’ claim 10 would
have been prima facie obvious to such a person. See In re
Vaeck, 947 F.2d 488, 493, 20 USPQ2d 1438, 1442 (Fed. Cir.
1991); In re O’Farrell, 853 F.2d 894, 902, 7 USPQ2d 1673, 1680
(Fed. Cir. 1988); In re Longi, 759 F.2d 887, 892-93, 225 USPQ
645, 648 (Fed. Cir. 1985).
Appeal No. 96-0251
Application 07/874,697
7
Appellants argue (brief, pages 8-9) that Lucisano merely
states the problem and makes appellants’ claimed method
“obvious to try” as that term is discussed in O’Farrell, 853
F.2d at 903, 7 USPQ2d at 1681. In that case, as pointed out
by appellants (brief, page 9), the court stated that in
previous cases, the court’s admonition that “obvious to try”
is not the standard for obviousness was directed toward two
kinds of error. See id. “In some cases, what would have been
‘obvious to try’ would have been to vary all parameters or try
each of numerous possible choices until one possibly arrived
at a successful result, where the prior art gave either no
indication of which parameters were critical or no direction
as to which of many possible choices is likely to be
successful.” See id. In the present case, as discussed
above, Lucisano would have indicated to one of ordinary skill
in the art that electrode shielding is desirable and that
using electrode shielding is likely to be successful. In the
other cases referred to by the court in O’Farrell, “what was
‘obvious to try’ was to explore a new technology or general
approach that seemed to be a promising field of
Appeal No. 96-0251
Application 07/874,697
8
experimentation, where the prior art gave only general
guidance as to the particular form of the claimed invention or
how to achieve it”. See id. As discussed above, Lucisano
provides more than general guidance as to the particular form
of the claimed invention but, rather, discloses maintaining
the reference electrode at high impedance and indicates that
adequate shielding of the electrodes is desirable. The
present case therefore does not fit into either of the groups
of cases discussed by the court in O’Farrell. Consequently,
we are not persuaded by appellants’ argument. Appellants also
rely upon In re Dow Chemical Co., 837 F.2d 469, 472, 5 USPQ2d
1529, 1531 (Fed. Cir. 1988) and In re Tomlinson, 363 F.2d 928,
933, 150 USPQ 623, 627 (CCPA 1966), but in those cases the
references did not provide the guidance toward the claimed
invention provided by Lucisano as discussed above.
For the above reasons, we conclude, based on the
preponderance of the evidence, that the invention recited in
appellants’ claims 10, 11/10, 12, 13, 14/10, 14/12 and 14/13
would have been obvious to one of ordinary skill in the art
within the meaning of 35 U.S.C. § 103 over Lucisano.
Appeal No. 96-0251
Application 07/874,697
A discussion of Perley is not necessary to our decision.3
9
Accordingly, we affirm the rejections of these claims over
Lucisano alone or in view of Perley.3
Rejection of claims 1, 2, 7, 8, 11/1, 11/2, 11/7,
11/8, 14/1, 14/2, 14/7 and 14/8 over Lucisano
in view of Hersch, Dahms or Sabins
Appellants’ claim 7 recites that the polarization of the
working electrode and reference electrodes is periodically
changed to drive electrodeposited material from the working
electrode back to the reference electrode.
Lucisano teaches that the silver/silver chloride
reference electrode had partly dissolved, that the working
electrode had acquired a layer of silver, and that “[i]n cases
of gradual sensor failure the original signal could be
restored by appropriate polarization treatment or by
replatinization of the working electrode” (page 739, left
column, second full paragraph). This teaching of use of a
polarization treatment to restore the signal after the
transfer of silver from the reference electrode to the working
electrode would have fairly suggested, to one of ordinary
skill in the art, periodically changing the polarization of
Appeal No. 96-0251
Application 07/874,697
A discussion of Hersch, Dahms and Sabins is not4
necessary to our decision.
10
the reference electrode and working electrode to drive the
silver from the working electrode back to the reference
electrode. Thus, we sustain the rejection of claims 1, 2, 7,
8, 11/1, 11/2, 11/7, 11/8, 14/1, 14/2, 14/7 and 14/8 over the
applied references.4
Rejection of claims 3-6 over
Lucisano in view of Sabins
Appellants’ claim 3 recites that the sensor includes a
plurality of working electrodes or reference electrodes such
that only one of the electrodes is operative at any one time
and all of the electrodes are adapted to be connected
sequentially into the sensor circuit.
Sabins discloses a method for providing cathodic
protection for various types of structures by impressing
current upon the structures to maintain them at a
predetermined polarization (col. 1, lines 10-15 and 36-38;
col. 2, lines 31-37 and 64-69). A circuit for monitoring the
impressed current includes one or more reference cells which
can be silver/silver chloride half cells and which are
Appeal No. 96-0251
Application 07/874,697
11
submerged in an electrolyte (col. 2, lines 46-47 and 53-60).
When more than one reference cell is used, while a cell is
being rejuvenated by reversing the polarity between the
reference cell and the structure, one reference cell is always
connected to the millivoltmeter to provide continuous
monitoring (col. 7, lines 36-75; col. 8, lines 11-14).
Lucisano teaches that when the silver/silver chloride
reference electrode has partially dissolved and a layer of
silver has been formed on the working electrode, a
polarization treatment can be carried out to restore the
signal (page 739, left column, second full paragraph). The
teaching by Sabins of use of multiple reference electrodes
adapted to be connected sequentially to the circuit such that
a reference electrode always is in service while a reference
electrode is being rejuvenated by a polarization treatment
(col. 7, lines 36-75; col. 8, lines 11-14) would have fairly
suggested, to one of ordinary skill in the art, connecting
multiple reference electrodes in the Lucisano sensor such that
one is always in service during the disclosed polarization
treatment.
Appellants argue that there is no reason to believe that
Appeal No. 96-0251
Application 07/874,697
12
Sabins’ multiple electrodes would solve Lucisano’s service
life problems (brief, page 12). For the above reason, we are
not persuaded by this argument as it relates to the problem
disclosed by Lucisano of silver forming on the working
electrode (page 739, left column, second full paragraph).
Even regarding Lucisano’s teaching of abrupt sensor failure
caused by silver dendrite formation between the working and
reference electrodes (see id.), the above teaching by Sabins
would have fairly suggested, to one of ordinary skill in the
art, using multiple electrodes in the circuit and switching to
another electrode when dendrites have formed, in order to
extend the life of the sensor.
For the above reasons, we affirm the rejection of claims
3-6 over Lucisano in view of Sabins.
Rejection of claims 9, 11/9 and 14/9
over Lucisano in view of Krebs
Appellants’ claim 9 recites that a continuous cathodic
current is applied to the reference electrode.
Krebs discloses a device for protecting the cathodes in
electrolytic cells used for decomposing alkaline chlorides
(col. 1, lines 1-3). Krebs applies a protection current to a
Appeal No. 96-0251
Application 07/874,697
13
cell preferably before the electrolysis current to the cell
has been stopped (col. 3, lines 3-31). The cell, under the
action of the protective current, may be submitted to any
desired operation such as cleaning (col. 3, lines 48-51).
The examiner argues that it would have been obvious to
one of ordinary skill in the art to use Krebs’ protection
current in Lucisano’s sensor in order to minimize the
dissolution of the silver/silver chloride reference electrode
(answer, pages 6-7). The examiner, however, provides no
evidence that Krebs’ protection current would have this
effect. Thus, we find that the examiner has not established a
factual basis which is sufficient to support a conclusion of
obviousness of the invention recited in appellants’ claims 9,
11/9 and 14/9. We therefore do not sustain the rejection of
these claims.
DECISION
The rejections under 35 U.S.C. § 103 of claims 10, 11/10,
12, 13, 14/10, 14/12 and 14/13 over Lucisano alone or in view
of Perley, claims 1, 2, 7, 8, 11/1, 11/2, 11/7, 11/8, 14/1,
14/2, 14/7 and 14/8 over Lucisano in view of Hersch, Dahms or
Appeal No. 96-0251
Application 07/874,697
14
Sabins, and claims 3-6 over Lucisano in view of Sabins, are
affirmed. The rejection of claims 9, 11/9 and 14/9 over
Lucisano in view of Krebs is reversed.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED-IN-PART
CHUNG K. PAK )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOAN ELLIS )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
TERRY J. OWENS )
Administrative Patent Judge )
Appeal No. 96-0251
Application 07/874,697
15
TJO/caw
Brown, Martin, Haller & McClain
1660 Union St.
San Diego, CA 92101
Appeal No. 96-0251
Application 07/874,697
16
APPENDIX
3. A method for extending the service life of
implantable sensors containing corrodible electrodes within a
potentiostat sensor circuit having a sensor having a
corrodible reference electrode, at least one noble metal
cathodic working electrode, and at least one noble metal
anodic counter electrode maintained at a low impedance, which
comprises including in said sensor a plurality of working or
reference electrodes, with only one of said plurality of
electrodes operative at any one time, with all of said
electrodes adapted to be connected sequentially into the
sensor circuit.
7. A method for extending the service life of
implantable sensors containing corrodible electrodes within a
potentiostat sensor circuit having a sensor having a
corrodible reference electrode, at least one noble metal
cathodic working electrode, and at least one noble metal
anodic counter electrode maintained at a low impedance, which
comprises periodically changing the polarization of said
working and reference electrodes so as to drive
electrodeposited material from the working electrode back to
the reference electrode.
9. A method for extending the service life of
implantable sensors containing corrodible electrodes within a
potentiostat sensor circuit having a sensor having a
corrodible reference electrode, at least one noble metal
cathodic working electrode, and at least one noble metal
anodic counter electrode maintained at a low impedance, which
comprises applying to said reference electrode a cathodic
current.
10. A method for extending the service life of
implantable sensors containing corrodible electrodes within a
potentiostat sensor circuit having a sensor having a
corrodible reference electrode, at least one noble metal
cathodic working electrode, and at least one noble metal
anodic counter electrode maintained at a low impedance, which
comprises increasing the input impedance at the reference
Appeal No. 96-0251
Application 07/874,697
17
electrode and shielding said reference electrode.