  United States Court of Appeals
      for the Federal Circuit
              __________________________

                  PEI-HERNG HOR,
                  Plaintiff-Appellant,

                         and
                  RULING MENG,
                  Plaintiff-Appellant,

                           v.
              CHING-WU “PAUL” CHU,
                 Defendant-Appellee.
              __________________________

                      2011-1540
              __________________________

    Appeal from the United States District Court for the
Southern District of Texas in case no. 08-CV-3584, Judge
Keith P. Ellison.
               __________________________

              Decided: November 14, 2012
              __________________________

   JOE W. BEVERLY, Dow Golub Remels & Beverly, LLP,
of Houston, Texas, argued for plaintiff-appellant Pei-
Herng Hor. Of counsel on the brief was WILLIAM P.
JENSEN, Crain Caton & James, of Houston, Texas.
HOR   v. CHU                                                2


   BRENT C. PERRY, Law Office of Brent C. Perry, of
Houston, Texas, argued for plaintiff-appellant, Ruling
Meng. Of counsel on the brief was GORDON G. WAGGETT,
Gordon G. Waggett, P.C., of Houston, Texas.

   LESTER L. HEWITT, Akin Gump Strauss Hauer & Feld
LLP, of Houston, Texas, argued for defendant-appellee.
With him on the brief was REHAN M. SAFIULLAH.
              __________________________

   Before NEWMAN, PROST, and REYNA, Circuit Judges.
      Opinion for the court filed by Circuit Judge PROST.
      Concurring opinion filed by Circuit Judge REYNA.

PROST, Circuit Judge.

     Appellants Pei-Herng Hor (“Hor”) and Ruling Meng
(“Meng”) filed this suit against Appellee Ching-Wu Chu
(“Chu”) under 35 U.S.C. § 256 for correction of inventor-
ship of U.S. Patent Nos. 7,056,866 (“’866 patent”) and
7,709,418 (“’418 patent”). The district court granted
Chu’s motion for summary judgment, finding that Hor’s
and Meng’s claims were barred by laches or, alternatively,
by equitable estoppel. For the reasons set forth below, we
affirm in part, reverse in part, vacate in part, and remand
for further proceedings consistent with this opinion.

                       I. BACKGROUND

    The facts of this case, including the underlying tech-
nology, are thoroughly detailed in the district court’s
summary judgment opinion, Hor v. Chu, 765 F. Supp. 2d
903 (S.D. Tex. 2011). We accordingly limit our discussion
to those facts that are relevant to the current appeal.
3                                                HOR   v. CHU


     Hor and Meng claim that they are joint inventors of
the ’866 and ’418 patents. Hor and Meng worked with
Chu in the physics research lab at the University of
Houston, performing research related to high tempera-
ture superconducting compositions. Id. at 906. Chu was
a professor of physics, Hor was a graduate student and
one of Chu’s research assistants, and Meng worked in
Chu’s research group as an independent materials scien-
tist. Id.

    The ’866 and ’418 patents at issue in this inventorship
dispute generally relate to superconducting compositions
with transition temperatures higher than the boiling
point of liquid nitrogen. The ’866 patent is titled “Super-
conductivity in Square-Planar Compound Systems.” It
was filed on March 26, 1987, and issued on June 6, 2006.
The ’418 patent is titled “High Transition Temperature
Superconducting Compositions.” It was filed on January
23, 1989, and issued on May 4, 2010. The compositions
claimed in the ’866 and ’418 patents were conceived
between November 1986 and March 1987, and Chu is the
sole named inventor on both patents. Id.

    In December 2008, Hor filed a complaint against Chu,
asserting a claim for correction of inventorship of the ’866
patent under 35 U.S.C. § 256. In March 2010, the district
court granted Meng’s motion to intervene to assert her
own § 256 claim against Chu. In June 2010, shortly after
the ’418 patent issued, Hor and Meng filed motions for
leave to amend their complaints to add a § 256 inventor-
ship claim with respect to the ’418 patent, which the
district court granted.

   Chu moved for summary judgment that Hor’s and
Meng’s § 256 claims were barred by laches because Hor
and Meng knew or should have known by as early as 1987
HOR   v. CHU                                               4


that they were not named inventors on the patent appli-
cations that ultimately issued as the ’866 and ’418 pat-
ents. The district court agreed that laches barred the
inventorship claims. According to the district court, Hor’s
and Meng’s inventorship claims arose before the patents
issued, and they knew or should have known of their
claims by the early 1990s at the latest. Hor, 765 F. Supp.
2d at 918. Because Hor did not file suit until 2008 and
Meng did not intervene until 2010, the court concluded
that a presumption of laches attached to their claims and
that neither Hor nor Meng sufficiently rebutted that
presumption. Id. at 918-20. The district court addition-
ally entered judgment in favor of Chu on Hor’s and
Meng’s unclean hands defense.1 Id. at 920-22. In the
alternative, the district court sua sponte determined that
the inventorship claims were barred by equitable estop-
pel. Hor and Meng have appealed, and we have jurisdic-
tion under 28 U.S.C. § 1295(a).

                      II. DISCUSSION

    On appeal, Hor and Meng challenge the district
court’s finding that their inventorship claims were barred
either by laches or, alternatively, by equitable estoppel.
Additionally, Meng appeals the district court’s entry of
judgment in favor of Chu on Meng’s unclean hands de-
fense. We address each issue in turn.


         1  In the district court, Chu moved for either a
dismissal of the unclean hands defenses under Federal
Rule of Civil Procedure 12(b)(6) for failure to state a claim
or, alternatively, for summary judgment under Federal
Rule of Civil Procedure 56. Although the district court’s
Final Judgment “dismissed” these defenses, from what we
can discern from the district court’s opinion, the court
appears to have resolved this issue under Rule 56.
5                                                 HOR   v. CHU


                         A. Laches

    To prevail on a defense of laches, a defendant must
establish that (1) the plaintiff’s delay in filing a suit was
“unreasonable and inexcusable,” and (2) the defendant
suffered “material prejudice attributable to the delay.”
A.C. Aukerman v. R.L. Chaides Constr. Co., 960 F.2d
1020, 1028 (Fed. Cir. 1992). For inventorship claims
under § 256, a delay of six years after a claim accrues
creates a rebuttable presumption of laches. Advanced
Cardiovascular Sys. v. SciMed Life Sys., 988 F.2d 1157,
1163 (Fed. Cir. 1993). When reviewing a laches decision
rendered on summary judgment, this court reviews for an
abuse of discretion unless genuine issues of material fact
preclude summary judgment. Ultimax Cement Mfg. Corp.
v. CTS Cement Mfg. Corp., 587 F.3d 1339, 1349 (Fed. Cir.
2009) (“[I]f genuine issues of material fact preclude sum-
mary judgment of laches, ‘we need not apply [the abuse of
discretion] standard[] of review’ that generally applies to
laches.” (quoting Wanlass v. Fedders Corp., 145 F.3d
1461, 1463 (Fed. Cir. 1998))) (second and third alterations
in original); see also Aukerman, 960 F.2d at 1039 (“[T]he
standard of review of the conclusion of laches is abuse of
discretion.”).

    On appeal, Hor and Meng argue that the district court
erred in finding that their inventorship claims accrued
before the ’866 and ’418 patents issued. According to Hor
and Meng, because a 35 U.S.C. § 256 cause of action does
not arise until the patent issues, the laches clock accord-
ingly cannot begin to run prior to issuance. Here, because
Hor and Meng filed suit within six years of the issuance of
the ’866 and ’418 patents, they contend that a presump-
tion of laches should not apply. Chu, in contrast, main-
tains that the laches period can begin pre-patent
issuance, where, as here, the purported inventors knew or
HOR   v. CHU                                                 6


should have known of the potential inventorship dispute
before the patent issued.

    We agree with Hor and Meng. Section 256 creates a
private cause of action to correct inventorship in an
issued patent:

      Whenever through error a person is named in an
      issued patent as the inventor, or through error an
      inventor is not named in an issued patent and
      such error arose without any deceptive intention
      on his part, the Director may, on application of all
      the parties and assignees, with proof of the facts
      and such other requirements as may be imposed,
      issue a certificate correcting such error.

      The error of omitting inventors or naming persons
      who are not inventors shall not invalidate the
      patent in which such error occurred if it can be
      corrected as provided in this section. The court be-
      fore which such matter is called in question may
      order correction of the patent on notice and hear-
      ing of all parties concerned and the Director shall
      issue a certificate accordingly.

35 U.S.C. § 256 (2006) (emphasis added).

    In Aukerman, this court applied the six-year pre-
sumption of laches to a patentee’s claim of infringement,
holding that the laches clock did not start to run—at the
earliest—until the patent issued:

      The period of delay is measured from the time the
      plaintiff knew or reasonably should have known of
      the defendant’s alleged infringing activities to the
      date of suit. However, the period does not begin
      prior to issuance of the patent.
7                                                 HOR   v. CHU


960 F.2d at 1032 (emphases added).

    Advanced Cardiovascular adopted Aukerman’s six-
year laches presumption for § 256 correction of inventor-
ship claims and held that the laches period began when
“the omitted inventor knew or should have known of the
issuance of the patent.” 988 F.2d at 1163. Advanced
Cardiovascular, however, did not address the precise
question presented here: Does the laches period for a
§ 256 claim begin to run before a patent issues when the
omitted inventors knew or should have known prior to
patent issuance that their names were omitted from the
patent application? We conclude that the answer is no.

    A § 256 claim for correction of inventorship does not
accrue until the patent issues. The reason is simple: that
is what the language of the provision requires. § 256
(“Whenever through an error a person is named in an
issued patent as the inventor, or through error an inven-
tor is not named in an issued patent . . . .”) (emphases
added); see also HIF Bio, Inc. v. Yung Shin Pharms.
Indus. Co., 600 F.3d 1347, 1354 (Fed. Cir. 2010) (“Once a
patent issues, . . . 35 U.S.C. § 256 provides a private right
of action to challenge inventorship . . . .”). Under well-
established laches principles, “[a] cause of action cannot
be barred by laches before it accrues; it is never extinct
when it comes into existence.” Davidson v. Grady, 105
F.2d 405, 412 (5th Cir. 1939); see also Lamb v. Powder
River Live Stock Co., 132 F. 434, 443 (8th Cir. 1904)
(“Nothing could be more unreasonable or more certainly
violative of constitutional prohibitions than to bar rights
of action because of the lapse of time prior to their ac-
crual, when they could not have been exercised.”).

    Here, the district court found that the laches period
for Hor’s and Meng’s § 256 claims started to run pre-
HOR   v. CHU                                               8


patent issuance—i.e., before the § 256 claims actually
accrued—because Hor’s and Meng’s inventorship claims
were not cabined to a claim under § 256. Instead, relying
on the potential availability of certain procedures to
correct inventorship while a patent application is still
pending before the U.S. Patent and Trademark Office
(“PTO”)—namely, petitioning for correction of inventor-
ship under 35 U.S.C. § 116 or initiating a 35 U.S.C. § 135
interference proceeding—the district court determined
that the laches period for inventorship claims begins
“when a plaintiff knew or should have known that the
defendant filed a patent application covering his alleged
inventive contributions and failed to name him as an
inventor, regardless of whether such notice occurred prior
to the patent’s issuance.” Hor, 765 F. Supp. 2d at 916.
The district court apparently found that §§ 116 and 135
proceedings were adequate substitutes for a § 256 inven-
torship claim such that the failure to seek a correction of
inventorship pursuant to one of those statutory provisions
prior to patent issuance could prevent an omitted inven-
tor from later bringing a § 256 claim. We disagree.

    Nothing in the plain language of § 256 or the accom-
panying regulations2 indicates that the failure to chal-
lenge inventorship before the PTO can potentially bar an
inventor from later contesting inventorship under § 256.
And imposing such a limitation runs afoul of our instruc-
tion that § 256 be “interpreted . . . broadly” to protect the
“public interest of assuring correct inventorship designa-
tions on patents.” Chou v. Univ. of Chi., 254 F.3d 1347,
1358 (Fed. Cir. 2001).




         2  The regulation implementing 35 U.S.C. § 256
is 37 C.F.R. § 1.324.
9                                               HOR   v. CHU


    Moreover, the specific procedural rules governing
§§ 116 and 135 further convince us that the district
court’s reliance on these purported alternative remedies
to support its laches analysis was misplaced. With re-
spect to § 116, for example, Chu does not dispute that
inventorship correction under this provision requires
consent of all the parties. Chu Supp. Br. 6; see also 37
C.F.R. § 1.48. In this case—as in most § 256 cases
brought by an omitted inventor—Hor’s and Meng’s inven-
torship is contested. Thus, § 116 likely was not an avail-
able avenue for Hor and Meng to correct their omitted
inventorship while the applications for the ’866 and ’418
patents were pending before the PTO.

    Regarding interferences, § 135(b)(1) allows for an in-
terference challenging an issued patent if the claim
provoking the interference was made within one year of
the challenged patent’s issuance.3 Because a party can
provoke an interference post-issuance of the challenged
patent, the availability of an interference proceeding does
not persuade us that a § 256 claim can accrue pre-
issuance for laches purposes.4

        3   While the underlying patent applications were
pending before the PTO, in 1999 Congress amended 35
U.S.C. § 135 to divide original paragraph (b) into para-
graphs (b)(1) and (b)(2). Consolidated Appropriations Act
of 2000, Pub. L. No. 106-113, § 1000 (a)(9), 113 Stat. 1501
(1999). Post-amendment paragraph (b)(1) corresponds
with pre-amendment § 135(b). Paragraph (b)(2) “creates
a one year bar relative to published patent applications.”
Regents of the Univ. of Cal. v. Univ. of Iowa Research
Found., 455 F.3d 1371, 1374 n.1 (Fed. Cir. 2006).
       4    We additionally note that prior decisions of
this court have treated a § 256 claim as an available
alternative to an interference proceeding, even when the
omitted inventor declined to initiate an interference
HOR   v. CHU                                           10


    Finally, while we recognize that the prompt resolution
of inventorship disputes certainly is a desirable goal,
there may be circumstances in which it would be ineffi-
cient to require an omitted inventor to initiate an inven-
torship dispute while the application is still pending.
Throughout the back-and-forth negotiation between the
patentee and the PTO examiner, the original claims are
routinely narrowed or even cancelled. Thus, in many
cases, an omitted inventor may not know whether he or
she has a cognizable inventorship claim until the exami-
nation concludes and the patent finally issues.

    Accordingly, for these reasons, we continue to apply
the general rule set forth in Advanced Cardiovascular
and hold that the laches period for a § 256 correction of
inventorship claim begins to run when “the omitted
inventor knew or should have known of the issuance of
the patent,” regardless of whether the omitted inventor
knew or should have known of the omitted inventorship
while the patent application was pending before the PTO.
Here, Hor and Meng filed their claims within six years of
the issuance of the ’866 and ’418 patents; the district
court, therefore, legally erred in finding that a presump-
tion of laches attached to these claims. The district
court’s judgment in favor of Chu based on the affirmative
defense of laches consequently is reversed.

               B. Unclean Hands Doctrine

    Under the unclean hands doctrine, “a [plaintiff] may
be able to preclude application of the laches defense with
proof that the [defendant] was itself guilty of misdeeds


despite knowledge that the challenged application was
pending before the PTO. See Eli Lilly & Co. v. Aradigm
Corp., 376 F.3d 1352, 1368 (Fed. Cir. 2004).
11                                             HOR   v. CHU


towards the [plaintiff].” Aukerman, 960 F.2d at 1038.
“[I]n the context of an inventorship action, a plaintiff
relying on the unclean hands doctrine to defeat a defense
of laches must show not only that the defendant engaged
in misconduct, but moreover that the defendant’s miscon-
duct was responsible for the plaintiff’s delay in bringing
suit.” Serdarevic v. Advanced Med. Optics, Inc., 532 F.3d
1352, 1361 (Fed. Cir. 2008).

     Here, Meng appeals the district court’s judgment in
favor of Chu with respect to her unclean hands defense.
According to Meng, unclean hands bars Chu’s laches
defense because Chu’s attorney, Charles Cox, allegedly
failed to inform Meng that her former co-worker, M.K.
Wu, placed Meng’s inventorship of the ’866 patent at
issue during an interference proceeding before the PTO.
Meng alleges that Cox’s actions caused her to delay in
bringing her inventorship claims. The district court
rejected this defense finding that (1) Meng failed to cite
any authority supporting the proposition that the conduct
of someone other than the defendant could support an
unclean hands claim or that Cox had a duty to inform
Meng of Wu’s allegations; (2) Cox’s alleged actions were
not egregious; and (3) Meng did not explain how she
would have acted differently had Cox actually informed
her of Wu’s assertions. The court concluded that “Meng’s
allegations against Cox do not rise to the level of egre-
gious conduct that would change the equities significantly
in her favor.” Hor, 765 F. Supp. 2d at 922.

    On appeal, Meng provides no authority that Cox’s ac-
tions can be imputed to Chu nor does she cite to any
evidence that she relied on Cox’s alleged actions in not
asserting her inventorship rights sooner. Instead, she
provides only the conclusory assertion that “[t]here is
certainly a genuine issue of material fact as to whether
HOR   v. CHU                                              12


the failure to inform Meng that her inventorship was at
issue delayed her bringing this suit and substantially
changed the equities in favor of Chu.” Meng’s Br. 25.
Unclean hands is an equitable defense within the sound
discretion of the district court, Princess Cruises, Inc. v.
United States, 397 F.3d 1358, 1369 (Fed. Cir. 2005) (“The
trial court has broad discretion under the doctrine of
unclean hands.”), and in this case we see no reason to
disturb the district court’s decision.

                  C. Equitable Estoppel

      In addition to determining that Hor’s and Meng’s
claims were barred by laches, the district court, in the
alternative, sua sponte found that Hor’s and Meng’s
inventorship claims were barred by equitable estoppel.
We conclude that this was error. Chu did not assert
equitable estoppel as an affirmative defense in his an-
swer, nor did he present this theory to the district court in
his motion for summary judgment. Estoppel, however, is
an affirmative defense that must be pled, Fed. R. Civ. P.
8(c)(1) (“In responding to a pleading, a party must af-
firmatively state any avoidance or affirmative defense,
including . . . estoppel . . . .”) (emphasis added), and the
failure to plead it can result in waiver, Davis v. Huski-
power Outdoor Equip. Corp., 936 F.2d 193, 198 (5th Cir.
1991) (“[A]n affirmative defense is waived unless pleaded
by the defendant.”). In the Fifth Circuit, whose law we
apply to this procedural issue, “an affirmative defense . . .
generally should not [be] raised sua sponte.” Kiser v.
Johnson, 163 F.3d 326, 328 (5th Cir. 1999) (quoting
Warnock v. Pecos Cnty., Tex., 116 F.3d 776, 778 (5th Cir.
1997)) (alterations in original); see also United States v.
Mitchell, 518 F.3d 740, 745 (10th Cir. 2008) (“[C]ourts
generally may not raise affirmative defenses sua sponte . .
. .”). Moreover, although a district court certainly has the
13                                                  HOR   v. CHU


discretion to sua sponte grant summary judgment, it
nevertheless must afford the losing party notice. Tolbert
v. Nat’l Union Fire Ins. Co., 657 F.3d 262, 271 (5th Cir.
2011) (“[W]e have vacated summary judgments and
remanded for further proceedings where the district court
provided no notice prior to granting summary judgment
sua sponte, even where summary judgment may have
been proper on the merits.” (quoting Leatherman v. Tar-
rant Cnty. Narcotics Intelligence & Coordination Unit, 28
F.3d 1388, 1398 (5th Cir. 1994))); see also Am. Flint Glass
Workers Union v. Beaumont Glass Co., 62 F.3d 574, 578
n.5 (3d Cir. 1995) (“[O]rders granting summary judgment
sua sponte endanger important rights and, unless waived
. . . , are likely to result in judicial inefficiency and depri-
vation to the rights of one of the parties.”). For these
reasons, we conclude that the district court erred in sua
sponte granting summary judgment based on the affirma-
tive defense of equitable estoppel in light of Chu’s failure
to assert that defense against Hor and Meng. The district
court’s judgment with respect to equitable estoppel ac-
cordingly is vacated.

                      III. CONCLUSION

     In sum, the district court’s judgment in favor of Chu
on his laches defense is reversed; the judgment in favor of
Chu with respect to Meng’s unclean hands defense is
affirmed; and the judgment in favor of Chu based on
equitable estoppel is vacated. The case is remanded to
the district court for further proceedings consistent with
this opinion.

      AFFIRMED-IN-PART, REVERSED-IN-PART,
       VACATED-IN-PART, AND REMANDED
  United States Court of Appeals
      for the Federal Circuit
              __________________________

                  PEI-HERNG HOR,
                  Plaintiff-Appellant,

                          and
                  RULING MENG,
                  Plaintiff-Appellant,

                           v.
              CHING-WU “PAUL” CHU,
                 Defendant-Appellee.
              __________________________

                      2011-1540
              __________________________

    Appeal from the United States District Court for the
Southern District of Texas in case no. 08-CV-3584, Judge
Keith P. Ellison.
               __________________________

REYNA, Circuit Judge, concurring.

    I agree with the majority that the presumptive six-
year period for laches on a claim to correct inventorship
under 35 U.S.C. § 256 does not begin to run before the
patent issues, even when the omitted inventor knew or
should have known of the omitted inventorship while the
patent application was pending before the PTO.
HOR   v. CHU                                               2


     Prior to enactment of § 256 in the Patent Act of 1952,
the various circuit courts grappled with the inflexible rule
that incorrect inventorship invalidated the patent. When
juxtaposed against the vexing question raised when the
patent was the work of several inventors acting jointly,
the rule presented questions acknowledged as “not free
from difficulty.” Iowa State Univ. Research Found., Inc. v.
Sperry Rand Corp., 444 F.2d 406, 408 (4th Cir. 1971); see
also Shreckhise v. Ritchie, 160 F.2d 593, 595 (4th Cir.
1947) (“[W]hen a patent is issued to one person for some-
thing which was jointly invented by several the patent is
invalid.”); William R. Thropp & Sons, Co. v. De Laski &
Thropp Circular Woven Tire Co., 226 F. 941, 947 (3d Cir.
1915) (“A patent for an invention claimed to be the joint
conception or invention of two, when in truth it is the
separate invention of but one, cannot be issued to both, or,
if issued, is void as to both.”); Tin Decorating Co. v. Metal
Package Corp., 37 F.2d 5, 7 (2d Cir. 1930).

    Congress enacted § 256 to provide relief against the
hardship (invalidation) brought on by mistake of inven-
torship. The legislative history is scant, but Senate and
House reports contain nearly identical language that
notes a correlation between 35 U.S.C. § 1161 and § 256.
Section 256 operates to permit “a bona fide mistake in

         1  In the pertinent part, 35 U.S.C. § 116 pro-
vides: “Whenever through error a person is named in an
application for patent as the inventor, or through error an
inventor is not named in an application, the Director may
permit the application to be amended accordingly, under
such terms as he prescribes.” Id. By its reference to “an
application,” § 116 is limited to applications pending at
the PTO. The regulation enforcing it, 37 C.F.R. § 1.48,
likewise implicitly makes clear that that the remedy
under § 116 is only available upon agreement of all the
parties. See 37 C.F.R. § 1.48(a)(1); see also 37 C.F.R.
§ 1.76(e).
3                                                  HOR   v. CHU


joining a person as an inventor or in failing to join a
person as an inventor to be corrected.” S. Rep. No. 82-
1979, at 7 (1952); H.R. Rep. No. 82-1923, at 9 (1952).
Unlike § 116, which specifies that the Director may
permit the patent application to be amended “under such
terms as he prescribes,” § 256 contains the imperative
that, upon an order from a court after notice and hearing
of all parties concerned, “the Director shall issue a certifi-
cate [correcting inventorship].”      Compare 35 U.S.C.
§ 116(c), with 35 U.S.C. § 256(b) (emphasis added).

    In his commentaries on the 1952 Patent Act, P.J.
Frederico observed that concurrence of all the parties was
required to correct misjoinder or nonjoinder at the PTO
under both § 116 and § 256. P.J. Frederico, Commentary
on the New Patent Act, 35 U.S.C.A., p. 1, at 27–28, 50
(1954). The final paragraph of § 256 was enacted to
permit courts to correct mistakes of inventorship absent
such consent. Id. at 50 (“If [the parties] do not concur, the
correction can only be made on order of a court as pro-
vided in the third paragraph.”); see also Sperry Rand, 444
F.2d at 408–09 (recognizing that although not part of the
legislative history, “Federico’s Commentary is entitled to
the weight ordinarily accorded an acknowledged authority
in his field”).

    The Fourth Circuit in Sperry Rand observed:

    The distinction which Federico noted between the
    power of the Commissioner, who can correct a
    patent only on consent of all parties, and that of a
    court, which can act without consent, has a ra-
    tional foundation. Patents “have the attributes of
    personal property.” 35 U.S.C. § 261; see 4 Deller’s,
    Walker on Patents 41 (2d ed. 1965). After the is-
    suance of a patent, the Commissioner lacks juris-
HOR   v. CHU                                              4


      diction over it save in interference proceedings,
      where the right of judicial review is assured. 35
      U.S.C. §§ 141, 146. The patentee has a vested
      property right that can be canceled, revoked, or
      annulled only by judicial proceedings that afford
      due process of law.

                                ****

      These well-established principles underlie the
      limitation that Congress placed on the Commis-
      sioner but not on the courts.

444 F.2d at 409.

    Because the final paragraph of § 256 was enacted to
provide specific judicial relief on issues of inventorship
without a concurrence by all parties, I agree with the
majority that a discovery standard for laches is inappro-
priate because it would obviate the judicial remedy under
§ 256. This is especially true since § 256 is a remedial
statute, meaning it was enacted to provide a specific form
of relief. See generally Sperry Rand, 444 F.2d 406.

    I diverge from the majority, however, when it reasons,
“while . . . prompt resolution of inventorship disputes
certainly is a desirable goal, there may be circumstances
in which it would be inefficient to require an omitted
inventor to initiate an inventorship dispute while the
application is still pending.” Maj. Op. at 10. There is no
doubt that prompt resolution of inventorship disputes is a
desirable goal. But the “inefficien[cy]” that the majority
identifies as competing with that goal—requiring an
omitted inventor to initiate an inventorship dispute while
the application is pending when a narrowing amendment
could still affect that inventorship claim—is inconsistent
5                                                HOR   v. CHU


with the desirability and efficiency wrought by prompt
resolution of inventorship issues. See id. If claims are
narrowed or even canceled during examination, the scope
of the patent becomes narrower, not broader. Shrinking
patent scope does not necessarily give rise to previously
nonexistent inventorship claims. Since an omitted inven-
tor would know whether he or she has a cognizable inven-
torship claim from the very beginning, there is no rational
reason to wait until the patent issues to assert a claim for
inventorship.

     I believe the differences between § 116 and § 256 cre-
ate a potential incentive to not challenge inventorship
until the patent issues notwithstanding actual knowledge
of the omission by an omitted inventor. Without a threat
of laches that would bar a § 256 claim to correct inventor-
ship within a specific time period beginning with the date
the omitted inventor is shown to have known of the
omission, the omitted inventor is encouraged to remain
silent as the applicant bears the costs of prosecution and
garners potentially lucrative licenses. Then, once the
patent issues, the omitted inventor can claim entitlement
to the fruit of applicant’s labors.

    While the application is non-final and undergoing ex-
amination, the PTO is well positioned to correct inventor-
ship errors. See, e.g., 35 U.S.C. §§ 116; 135(a); 37 C.F.R.
§ 1.48. Allowing omitted inventors to forego efficient PTO
inventorship correction processes needlessly burdens the
courts and weighs heavily on the patent system. Properly
understood, I believe policy considerations support a
conclusion contrary to the statutorily required one we
reach today, but it is up to Congress, not this court, to
amend the statute accordingly.
