Prosecution Disclaimers

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					  The University of Texas School of Law

              Presented:
    9th Annual Advanced Patent Law
                Institute

          October 27-29, 2004
             Austin, Texas




Prosecution Disclaimers




     George W. Jordan, III




                                          George W. Jordan, III
                                          Merchant & Gould, LLC
                                          Atlanta, Georgia 30303-1821


                                          gjordan@merchant-
                                          gould.com
                                          404-954-5088




      Continuing Legal Education     l   512-475-6700   l   www.utcle.org
                                              TABLE OF CONTENTS


I.    Introduction ..............................................................................................................................1

II.    Prosecution Disclaimers Versus Prosecution History Estoppel ...............................................1

III. Consistency Between Prosecution and Claim Interpretation ...................................................1

IV. “Reasonable Competitor” .........................................................................................................3

V. “Clear and Unmistakable” Versus Ambiguous.........................................................................5

VI. Strategies for Limiting Prosecution Disclaimer .......................................................................7

VII. Conclusion...............................................................................................................................8




                                                                  i
                                         TABLE OF AUTHORITIES

                                                FEDERAL CASES

Biodex Corp. v. Loredan Biomedical, Inc.,
       946 F.2d 850 (Fed. Cir. 1991)..............................................................................................1

CCS Fitness, Inc. v. Brunswick Corp.,
      288 F.3d 1359 (Fed. Cir. 2002) ...........................................................................................5

CVI/Beta Ventures, Inc. v. Tura LP,
      112 F.3d 1146 (Fed. Cir. 1997)............................................................................................2

Cordis Corp. v. Medtronic Avenue, Inc.,
       339 F.3d 1352 (Fed. Cir. 2003)........................................................................................6, 7

Cybor Corp. v. FAS Techs., Inc.,
      138 F.3d 1448 (Fed. Cir. 1998) ...........................................................................................4

Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.,
       234 F.3d 558 (Fed. Cir. 2000), rev’d, 535 U.S. 722 (2002) ...............................................1

Hilton Davis Chem. Co. v. Warner-Jenkinson, Co.,
       520 U.S. 17 (1997)...............................................................................................................1

Hockerson-Halberstadt, Inc. v. Avia Group International, Inc.,
      222 F.3d 951 (Fed. Cir. 2000)..............................................................................................4

IMS Tech., Inc. v. Haas Automation, Inc.,
      206 F.3d 1422 (Fed. Cir. 2000)............................................................................................3

Innova/Pure Water, Inc. v. Safari Water Filtration Systems, Inc., No. 04-1097,
       2004 U.S. App. LEXIS 16549 (Fed. Cir. August 11, 2004)................................................7

Jenkinson Co. v. Hilton Davis Chem. Co.,
2004 U.S. App. LEXIS 16549 (Fed. Cir. August 11, 2004)............................................................7

Markman v. Westview Instruments, Inc.,
     52 F.3d 967 (Fed. Cir. 1995), aff’d, 517 U.S. 370 (1996) ...................................................1

Northern Telecom Ltd. v. Samsung Electronics Co.,
       215 F.3d 1281 (Fed. Cir. 2000) ...........................................................................................5

Omega Engineering, Inc. v. Raytek Corp.,
     334 F.3d 1314 (Fed. Cir. 2003)................................................................................1, 5, 6, 8




                                                              ii
Rexnord Corp. v. Laitram Corp.,
      274 F.3d 1336 (Fed. Cir. 2001) .......................................................................................3, 6

Senmed, Inc. v. Ethicon, Inc.,
      888 F.2d 815 (Fed. Cir. 1989)..........................................................................................1, 2

Southwall Techs., Inc. v. Cardinal IG Co.,
      54 F.3d 1570 (Fed. Cir. 1995)..........................................................................................1, 2


                                               FEDERAL STATUTES

35 U.S.C. § 102................................................................................................................................8




                                                                iii
I.      Introduction

       What do Markman,1 Hilton Davis,2 Festo3 and Omega Eng’g, Inc. v. Raytek
Corp.4 have in common? All of these Federal Circuit decisions emphasize important
aspects of the public notice function. For Markman, it was claim construction. For
Hilton Davis, it was the doctrine of equivalents. For Festo, it was prosecution history
estoppel. For Omega Eng’g, it is the prosecution disclaimer doctrine.

II.     Prosecution Disclaimers Versus Prosecution History Estoppel

        Though at times confused with prosecution history estoppel, the prosecution
disclaimer doctrine is quite different. While prosecution history estoppel is a limit on
expansion of patent claim protection under the doctrine of equivalents, prosecution
disclaimer is a limit on literal patent claim protection through claim construction. Biodex
Corp. v. Loredan Biomedical, Inc., 946 F.2d 850, 862-63 (Fed. Cir. 1991)
(acknowledging the “clear line of distinction”). Prosecution history estoppel narrows the
range of equivalents by preventing recapture of subject matter surrendered during
prosecution. Southwall Techs., Inc. v. Cardinal IG Co., 54 F.3d 1570, 1578 (Fed. Cir.
1995). Prosecution disclaimer however narrows the ordinary meaning of claim terms by
excluding specific claim term interpretations that were disclaimed during prosecution.
Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1324 (Fed. Cir. 2003). Prosecution
history estoppel comes into play after no literal infringement is found. Southwall, 54
F.3d at 1578. In contrast, prosecution disclaimer is a preliminary consideration in
determining literal infringement. Id.

         The two doctrines yet have much in common. Both are based on the prosecution
history; both are types of surrenders; and both must balance the needs of meaningful
patent protection and adequate public notice. While Festo and its progeny have
underscored the importance of the prosecution history in the context of the doctrine of
equivalents, the prosecution history is no less important in the context of claim
construction. Prosecution disclaimer tends to be particularly important when claims fail
to fulfill the public notice function or when claims have undergone reexamination.

III.    Consistency Between Prosecution and Claim Interpretation

        In Senmed, Inc. v. Ethicon, Inc., 888 F.2d 815 (Fed. Cir. 1989), the Federal
Circuit applied the concept that a patentee cannot adopt a claim construction that is
inconsistent with the prosecution history. The patent in issue concerned surgical staplers.
888 F.2d at 816. Claim 1 recited a “means to constantly urge and advance said row of
staples along said anvil plate to place a forwardmost staple on said anvil surface.” Id. at


1
  Markman v. Westview Instruments, Inc., 52 F.3d 967 (Fed. Cir. 1995), aff’d, 517 U.S. 370 (1996).
2
  Hilton Davis Chem. Co. v. Warner-Jenkinson, Co., 62 F.3d 1512 (Fed. Cir. 1995), rev’d, Warner-
Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17 (1997).
3
  Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 234 F.3d 558 (Fed. Cir. 2000), rev’d, 535 U.S.
722 (2002).
4
  334 F.3d 1314 (Fed. Cir. 2003).
                                                   1
817. The claim construction issue was whether “on” the anvil surface must be interpreted
to mean “in physical contact” with the anvil surface. Id.

       In distinguishing the prior art, the applicant amended claim 1 to recite “on” in
describing the relationship between the staple and the anvil surface and to recite “closely
adjacent” in describing the relationship between a staple driver and the staple. Id. at 820.
The applicant thus knew the difference between “on” and “closely adjacent.” Id. Yet,
under the applicant’s interpretation of “on” as “juxtaposed,” “closely adjacent” and “on”
would mean the same thing. Id. at 819. Therefore, the Federal Circuit rejected the
applicant’s interpretation of “on” as “incontestably inconsistent” with the position the
applicant took during prosecution. Id. at 817-18.

       Senmed is not a prosecution disclaimer case because the prosecution history did
not narrow the ordinary meaning of “on.” Nevertheless, Senmed emphasizes the
importance of consistency between prosecution and claim interpretation. Because “on”
was given its ordinary meaning in the prosecution history, the applicant’s self serving,
post-hoc opinion testimony could not alter the public record, else the claim would
become a “nose of wax.” Id. at 819 (citations omitted).

        In Southwall Techs., Inc. v. Cardinal IG Co., 54 F.3d 1570 (1995), the Federal
Circuit expressed both the concept and the underlying rationale of the prosecution
disclaimer doctrine: “The prosecution history limits the interpretation of claim terms so
as to exclude any interpretation that was disclaimed during prosecution…Claims may not
be construed one way in order to obtain allowance and in a different way against accused
infringers.” 54 F.3d at 1576 (citations omitted); See CVI/Beta Ventures, Inc. v. Tura LP,
112 F.3d 1146, 1159 (Fed. Cir. 1997) (finding the patentee could not turn its back on the
meaning of “elasticity” embraced during prosecution). The patent in issue related to a
heated mirror that passes visible light, but reflects infrared light. Id. at 1573. The
invention involved sputter-deposited transparent metal layers separated by discrete
dielectric layers. Id. The accused sputtering process for forming a titanium oxide layer
was a two-step process, while the accused sputtering process for forming a zinc oxide
layer was a one-step process. Id. at 1574.

        The claim language in issue was a “sputter-deposited dielectric.” Id. at 1575. If
the “sputter-deposited dielectric” must be formed by a one-step sputtering process, then
the accused titanium oxide layer would not be a “sputter-deposited dielectric.” Id. at
1575-76. In an office action, the examiner interpreted sputter depositing as a two-step
process. Id. at 1576. In response, Southwall amended the claims to recite that the
dielectric layer can be laid down “directly” and “directly” converted to the oxide by the
presence of a suitable gaseous reactant. Id. Southwall thereby disclaimed a two-step
sputtering process for forming a dielectric layer and emphasized its one-step reactive
sputtering process. Id. Thus, the prosecution history limited the interpretation of
“sputter-deposited dielectric” to exclude any dielectric layer formed by a two-step
process. Id.

       IMS Tech., Inc. v. Haas Automation, Inc., 206 F.3d 1422 (Fed. Cir. 2000)
demonstrates that prosecution statements must be taken in context in assessing whether
they “clearly disclaim.” The patent in issue related to a control program for a machine
                                             2
tool. 206 F.3d at 1426. The invention permitted interactive programming of a machine
tool on the shop floor. Id. at 1426. The accused system stored programs in G- and M-
code format. Id. at 1427. The issue was whether prosecution statements caused a
disclaimer of the use of G- and M-codes impacting the meaning of the claim term “data
block.” Id. at 1433. During reexamination, the patentee distinguished the prior art by
emphasizing the interactive programming technique of the invention. Id. at 1433. The
patentee made reference to G- and M-codes in contrasting the invention and the prior art:

              The present invention utilizes an interactive display which
              operates in a question and answer format without resorting
              to the M and G codes of the machine tool….The interactive
              processing of the blocks enables the machine tool operator
              to perform the tasks of both the programmer and machinist
              on the shop floor.

Id. at 1433-34. The Federal Circuit concluded that the above statement taken in context
did not disclaim the use of G- and M-codes in the claimed invention:

              We agree with IMS that this statement, taken in context, as
              well as other statements made during prosecution and
              reexamination, do not disclaim the use of G- and M-codes
              in the claimed invention. The purpose of the statements
              was to emphasize the interactive nature of the invention as
              an improvement over the prior art programming method in
              which a user had to create a program line-by-line using
              only G- and M-codes. Thus, the claimed invention does
              not require the creation of a G- and M-code program; at the
              same time, however, the invention does not preclude the
              creation of a G- and M-code program so long as it is
              created using the claimed interactive inquiry process.

Id. at 1434. Because the format of a “data block” was irrelevant, “data block” was
construed as a “computer data structure containing the information needed by a machine
tool to perform a single machinery operation.” Id.

IV.    “Reasonable Competitor”

        While claims are read from the standpoint of one of ordinary skill in the art,
Rexnord Corp. v. Laitram Corp., 274 F.3d 1336, 1342 (Fed. Cir. 2001), the prosecution
history is read from the standpoint of a “reasonable competitor.” This is a practical
perspective given it is the competitor seeking to avoid infringement who must take its cue
from the public record of the patent:

              The prosecution history constitutes a public record of the
              patentee’s representations concerning the scope and
              meaning of the claims, and competitors are entitled to rely
              on those representations when ascertaining the degree of

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              lawful contact, such as designing around the claimed
              invention.

Hockerson-Halberstadt, Inc. v. Avia Group Int’l, Inc., 222 F.3d 951, 957 (Fed. Cir.
2000). From that perspective, the Federal Circuit examined the disclaimer issue in
Hockerson-Halberstadt. The patent in issue related to outer footwear. Id. at 952. The
invention involved a heel having a central groove and a double fin. Id. at 952-53. The
patent claim language was a “central longitudinal groove.” Id. at 954.

        During prosecution, the inventor canceled the original claims and replaced them
with three new independent claims reciting a “central longitudinal groove.” Id. at 953.
The inventor also submitted drawings comparing the features of the claimed invention to
a hypothetical prior art combination. Id. at 953 & 956. The inventor then distinguished
the prior art by arguing the claimed invention provided a “much narrower groove” for the
“totally different purpose” of involving as much of the underneath footwear surface as
possible in a cushioning and supporting function. Id. at 954 & 956. One of the
distinguished prior art references taught a shoe with a groove width greater than the
combined width of the two fins. Id. at 956. The Federal Circuit upheld the district
court’s decision holding that the inventor necessarily defined the “central longitudinal
groove” as requiring a width that must be less than the combined width of the two fins.
Id. The patentee’s argument that the prosecution statement was erroneous because the
patent figures show a wider groove was unavailing given it is well established that patent
drawings do not define precise proportions. Id. The Court declined the patentee’s
invitation to erase the inventor’s disavowal from the prosecution history, emphasizing the
importance of a public record upon which reasonable competitors form their business
strategies. Id.

         A “reasonable competitor” vantage point was also employed in Cybor Corp. v.
FAS Techs., Inc., 138 F.3d 1448 (Fed. Cir. 1998). The patent in issue related to pumps
used for dispensing volumes of liquid onto semiconductor wafers. Id. at 1451. The
initial claim language was a “second pumping means.” Id. at 1458. The accused product
was a dual stage pump. Id. at 1452. In order to overcome a prior art rejection, the
inventors characterized the prior art as providing a container separate from a conveying
pump. Id. at 1458. The inventors emphasized the separateness of the container, both
physically and functionally, as compared to the claimed invention. Id.

        The Cybor Court framed the question as “whether a competitor would reasonably
believe that the applicant had surrendered the relevant subject matter.” 138 F.3d at 1457
(citation omitted). The prosecution statements were not interpreted as precluding
coverage of every type of external reservoir. Id. at 1458. Instead, in view of the
“significant differences” between the prior art and the claimed invention, the statements
only disclaimed a physically unattached reservoir which has independent functionality.
Id. There was no disclaimer of a reservoir which is physically connected to the pump
and which only collects fluid to be dispensed by that pump. Id. Cybor is illustrative of
how the scope of the disclaimer must be congruent with the scope of the prosecution
statements. Cybor also shows that means-plus-function language is not immune from the
prosecution disclaimer doctrine.

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V.     “Clear and Unmistakable” Versus Ambiguous

        As recently as 2003, in Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314 (Fed.
Cir. 2003), the Federal Circuit pronounced a “clear and unmistakable” standard for the
prosecution disclaimer doctrine. The three patents related to a laser sighting system for
use on infrared thermometers. 334 F.3d at 1318. The patents taught methods for using
laser beams to visually outline the surface area encompassed by a field of view. Id. The
‘678 patent is a continuation in part of the ‘880 patent, and the ‘679 patent is a
continuation in part of the ‘678 patent. Id. at 1319. Claims 1 and 3 of the ‘880 patent
required a “means for causing said at least one laser beam to strike the periphery of the
energy zone for visibly outlining said entire zone.” Id. at 1321. Claims 16 and 18 of the
‘880 patent required a “means for causing said at least one laser beam to identify and
define both the center and only the periphery of said energy zone.” Id. at 1329.

        The Court began its claim construction analysis with the “heavy presumption”
that claim terms carry their full ordinary and customary meaning unless the patentee
unequivocally imparted a novel meaning to those terms or expressly relinquished claim
scope during prosecution. 334 F.3d at 1323 (citing CCS Fitness, Inc. v. Brunswick Corp.,
288 F.3d 1359, 1366 (Fed. Cir. 2002)). The well-established doctrine of prosecution
disclaimer is the fundamental precept in claim construction that falls into the latter
category. Id. at 1323. “[W]here the patentee has unequivocally disavowed a certain
meaning to obtain his patent, the doctrine of prosecution disclaimer attaches and narrows
the ordinary meaning of the claim congruent with the scope of the surrender.” Id. at
1324.

        To balance the importance of public notice and the right of patentees to seek
broad patent coverage, the Federal Circuit declines to apply the doctrine of prosecution
disclaimer where the alleged disavowal of claim scope is ambiguous. 334 F.3d at 1324.
For example, in Northern Telecom Ltd. v. Samsung Electronics Co., 215 F.3d 1281 (Fed.
Cir. 2000), “confusing” prosecution statements did not create a disclaimer for the claim
language “plasma etching.” Id. at 1295. The disclaimer issue was whether “plasma
etching” required the exclusion of ion bombardment. Id. at 1294. The inventor described
the prior art references as concerning a “totally different process.” Id. In an effort to
understand what “totally different process” meant to the inventor, the Court focused on
the paragraph from the applicant’s response that described the invention rather than the
paragraphs that described the prior art. Id. The Federal Circuit concluded that the
paragraph on the invention reflected a focus on plasma etching without including or
excluding ion bombardment. Id. The Court identified at lest three possible reasons why
the references were “totally different”: (i) plasma etching in the presence of boron
trihalide; (ii) gas plasma etching; or (iii) the presence of ion bombardment. Id. In sum,
the Court found the patentee had not defined “plasma etching” with “reasonable clarity
and deliberateness.” Id.

        Ambiguity based on silence probably best describes Rexnord Corp. v. Laitram
Corp., 274 F.3d 1336 (Fed. Cir. 2001). The patent in issue related to a transfer conveyor
for transferring articles between an upstream conveyor and a downstream conveyor
without manual intervention. 215 F.3d at 1339. The dispositive issue was whether the
claim term “portion” is limited to separate parts as opposed to separate or integral parts.
                                            5
Id. at 1341. The examiner’s statement concerning the “cantilevered portion” and the
“link module portion” was silent on whether the two portions were separate or integral.
Id. at 1346-47. Accordingly, the Court found the statement was “inconclusive”
concerning the proper meaning of “portion.” Id. at 1347. The Federal Circuit presumed
that the examiner fulfilled his obligation to give “portion” the “broadest reasonable
interpretation consistent with the specification” and that the examiner would have
required a specific amendment if separate structures were essential to patentability. Id.

       In Omega Eng’g, the Court found a “clear and unmistakable” disclaimer for the
claim language “to visibly outline.” 334 F.3d at 1326. In rejecting the examiner’s broad
assessment of claim scope, the patentee insisted that its invention directs energy at the
edge of the energy zone whereby temperature measurement is not affected. Id. at 1327.
Similarly, the patentee distinguished its laser from an incandescent lamp which cannot be
used to define an infrared heat zone accurately. Id. at 1326-27. The Federal Circuit
concluded that the patentee put the examiner and the public on notice of the invention’s
“crucial feature.” Id. at 1326. Based on this clear and unmistakable disclaimer, the
claimed function was construed as “causing of at least one laser beam to strike the
periphery of the energy zone for visibly outlining the entire energy zone, without adding
appreciable heat to the energy zone as to affect the accuracy of the temperature
measurement.” Id. at 1328.

        With respect to claims 16 and 18 of the ‘880 patent, the addition of the term
“only” before “the periphery” did not rise to the level of being an “unmistakable”
disclaimer. 334 F.3d at 1330. The Court rejected the imposition of a “sequential”
limitation based on the term “only.” Id. Though “only” was added to overcome
references cited by the examiner, the basis for the amendment was considered reasonably
amenable to more than one explanation. Id. “[T]here is more than one reasonable basis
for the amendment, rendering the intent underlying the amendment ambiguous and thus
negating the possibility of the disclaimer being unmistakable.” Id.

         In Cordis Corp. v. Medtronic Ave, Inc., 339 F.3d 1352 (Fed. Cir. 2003), cert.
denied, 124 S. Ct. 1426 (2004), the Federal Circuit had further occasion to apply the
“clear and unmistakable” standard. The patent in issue related to an expandable coronary
stent composed of a tubular member having a wall surface with slots formed therein. 339
F.3d at 1355. The claim language in issue was “slots formed therein.” Id. at 1356. The
district court held that the slots must be formed in the wall surface by the removal of
material. Id. at 1358. The inventor argued that the Wiktor prior art reference lacked a
wall surface having a plurality of slots and lacked slots disposed parallel to the
longitudinal axis of each tubular member. Id. at 1359. The Court determined the
inventor’s statement that the prior art lacked a wall surface having a plurality of slots was
not “clear.” Id. The inventor could have meant that the coiled wire was not a “wall
surface” or that the openings in the coil were not “slots.” Id. The patentee distinguished
Ersek, but did not dispute that the prior art device had a plurality of slots formed therein.
Id. at 1360. Because the patentee’s statements were amenable to multiple reasonable
interpretations, there was not a “clear and unmistakable” surrender of all stents that
lacked a wall surface from which material is removed to form slots. Id.



                                             6
        Another claim limitation construed by the Cordis Court was “substantially
uniform thickness.” 339 F.3d at 1360. Based on an expert witness affidavit addressing a
prior art model, the district court construed the limitation to require that the thickness of
the stent’s wall surface not vary by 0.001 inch or more. Id. Cordis distinguished the
prior art as having twice as thick walls, which was found by the Court to be the focus
rather than a specific thickness variation. Id. at 1361. The Federal Circuit found the
alleged disclaimer based on the affidavit ambiguous and thus not a “clear and
unmistakable” disclaimer. Id. Based on the file history, the Court concluded that there
was no “clear and unmistakable” disclaimer of any variation of thickness of 0.001 inch or
more. Id. at 1362.

        The Federal Circuit recently applied the “clear and unmistakable” standard in
Innova/Pure Water, Inc. v. Safari Water Filtration Systems, Inc., No. 04-1097, 2004 U.S.
App. LEXIS 16549 (Fed. Cir. August 11, 2004). The patent in issue related to a filter
assembly for a water bottle. Innova/Pure Water, 2004 U.S. App. LEXIS 16549, at *2.
The accused water bottle suspends a tube of filtering material in the mouth of the bottle
by means of an annular flange that rests on the mouth. Id. When a bottle cap is screwed
over the mouth, the cap contacts the annular flange and fixes the tube of filtering material
in position. Id. at *3. The disclaimer issue was whether the claim term “operatively
connected” required tenacious physical engagement between the tube of filtering material
and the cap. Id. at *5.

        During prosecution, the patentee argued that the prior art lacked the various forms
of physical connections that were recited in the dependent claims. Id. at *31.
Recognizing that limitations in dependent claims do not limit independent claims, the
Court concluded that the patentee did not “clearly and unambiguously” disavow
mechanical connections where the filter tube is tenaciously physically engaged to the cap.
Id. at *31-32.

        The Court also considered the applicant’s arguments in response to a rejection of
claim 17. Id. at *33. The applicant argued that the prior art showed an axial filter using a
flange to suspend the ion exchange resins which operate in axial flow mode. Id. Because
the Court could not distinguish whether the applicant was disavowing the use of the filter
or the flange and the examiner retreated from her position following a telephone
interview, there was no “clear and unambiguous” disavowal of caps and filters connected
by mechanical means short of tenacious physical engagement. Id. at *34.

VI.    Strategies for Limiting Prosecution Disclaimer

        For prosecutors, one viable option for limiting the risk of prosecution disclaimer
is to conduct examiner interviews in place of written arguments whenever feasible. This
approach could significantly reduce the number of arguments in the public record. From
both a quantitative and a qualitative standpoint, an interview summary in the record is
preferable to a full-blown response to an office action.

        Omega Eng’g shows the potential impact of examiner interviews on prosecution
disclaimer. Omega and the examiner had four telephonic interviews within the span of a
week, culminating in an amendment. 334 F.3d at 1331. Disclaimers could not be drawn
                                             7
from the mere statements “[r]esponsive to numerous telephone communications with the
Examiner” and “to clearly define the invention over the prior art.” Id. As expressed by
the Omega Court, to conclude otherwise would require an “ungrounded leap of logic.”
Id. Thus, examiner interviews can be a significant impediment to finding a “clear and
unmistakable” disclaimer.

        Another option for limiting the risk of prosecution disclaimer is to present
amendments without arguments whenever feasible. When a reason for an amendment is
not expressed, there could be multiple reasonable bases for the amendment. In such a
situation, a “clear and unmistakable” disclaimer is unlikely. See Omega Eng’g, 334 F.3d
at 1330 (finding ambiguity surrounding an amendment adding “only” precluded an
“unmistakable” disclaimer).

       A further option to limit the risk of prosecution disclaimer is to compartmentalize
arguments based on the relevant claims. Treating claim-specific arguments as global
arguments could unintentionally extend the scope of prosecution disclaimer to all
pending claims in a patent application. One manner of practicing this option is to use
claim number headings in a response to an office action to separate arguments by the
relevant claims as shown below:

                                          ****

       35 U.S.C. § 102

            Claims 1-5
       Argument X

            Claims 6-10
       Argument Y
                                          ****

For the above example, the concept is to confine Argument X to claims 1-5 and
Argument Y to claims 6-10. This approach could prove effective provided the claim
term in issue is not common to both claim sets. In the same vein, caution should be
exercised with closing statements like “for the above reasons, all claims are submitted to
be allowable,” else such statements could expose each pending claim to prosecution
disclaimer.

        Because prosecution disclaimer is specific to claim terms, another option to limit
prosecution disclaimer is to employ differing claim language among the independent
claims. That way, if a disclaimer arises, it can be limited to its particular claim set where
the claim language in issue appears.

VII.   Conclusion

       For litigators, prosecution disclaimer is perhaps the last thing that comes to mind
when one considers ways of overcoming the presumption of ordinary meaning.
Nevertheless prosecution disclaimer is a viable way of ensuring that the patentee takes
                                             8
full responsibility for its representations during prosecution that impact claim
interpretation. Unlike disclaimers based on the specification, prosecution disclaimer
doctrine is focused on the public notice function. For prosecutors, prosecution disclaimer
might naturally take a “back seat” to getting a case allowed. Yet, if prosecution
disclaimer is made a priority, opportunities to limit disclaimers can be seized to ensure
meaningful patent protection.

        This leads us to the ultimate question: When are prosecution statements “clear
and unmistakable” disclaimers? Based on the case law discussed above, the answer
likely depends on the following sort of questions:

   •   Is the feature in issue ancillary to the overall purpose of the prosecution
       statements?
   •   Are the prosecution statements as a whole directed to the feature in issue?
   •   Do the prosecution statements suggest that the feature in issue is crucial?
   •   Was the feature in issue raised by the examiner?
   •   Are the only prosecution statements in issue statements by the examiner?
   •   Were the prosecution statements accompanied by a claim amendment focusing on
       the same feature in issue?
   •   Is an amendment the only basis for the alleged disclaimer?
   •   Are there multiple prosecution statements directed to the same feature in issue?
   •   Were the prosecution statements focused on the claim language in issue?
   •   Is there a broad ordinary meaning for the claim language in issue?
   •   Do the prosecution statements describe the invention or just the prior art?
   •   Do the prosecution statements indicate significant differences between the prior
       art and the claimed invention?
   •   Is there more than one reasonable interpretation of the prosecution statements?

For the prosecution disclaimer doctrine to effectively serve the public notice function,
great attention must be paid to the prosecution history to recognize prosecution
statements that disclaim specific claim interpretations.




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