  United States Court of Appeals
      for the Federal Circuit
              __________________________

       MAGSIL CORPORATION AND
MASSACHUSETTS INSTITUTE OF TECHNOLOGY,
           Plaintiffs-Appellants,
                           v.
 HITACHI GLOBAL STORAGE TECHNOLOGIES,
 INC., HITACHI AMERICA, LTD., HITACHI DATA
   SYSTEMS CORPORATION, AND SHENZHEN
        EXCELSTOR TECHNOLOGY LTD.,
              Defendants-Appellees.
              __________________________

                      2011-1221
              __________________________

    Appeal from the United States District Court for the
District of Delaware in Case No. 08-CV-0940, Judge
Harvey Bartle, III.
              ___________________________

               Decided: August 14, 2012
             ___________________________

    STEVEN J. POLLINGER, McKool Smith, P.C., of Austin,
Texas, argued for the plaintiffs-appellants. With him on
the brief were CRIAG N. TOLLIVER, JOEL L. THOLLANDER
and LILAN REN. Of counsel on the brief were JACK B.
BLUMENFELD and RODGER D. SMITH, II, Morris, Nichols,
Arsht & Tunnell LLP, of Wilmington, Delaware.
MAGSIL CORP   v. HITACHI GLOBAL                          2


   EDWARD R. REINES, Weil, Gotshal & Manges LLP, of
Redwood Shores, California, argued for defendants-
appellees. Of counsel on the brief were DOUGLAS E.
LUMISH, JEFFREY G. HOMRIG and LAWRENCE OKEY
ONYEJEKWE, JR., Kasowitz, Benson, Torres & Friedman,
LLP, of San Francisco, California.     Of counsel was
FREDERICK L. COTTRELL, III, Richards, Layton & Finger,
PA, of Wilmington, Delaware.
              __________________________

Before RADER, Chief Judge, O’MALLEY and REYNA, Circuit
                       Judges.
RADER, Chief Judge.
    The United States District Court for the District of
Delaware granted summary judgment that claims 1-5, 23-
26, and 28 of U.S. Patent No. 5,629,922 (“the ’922 patent”)
are invalid for a lack of enablement. MagSil Corp. v.
Seagate Tech., 764 F. Supp. 2d 674 (D. Del. 2011). Be-
cause the record supports the trial court’s judgment, this
court affirms.
                              I.
    Appellant Massachusetts Institute of Technology is
the assignee of the ’922 patent and appellant MagSil
Corporation is the patent’s exclusive licensee. The appli-
cation leading to the ’922 patent was filed in March 1995
and issued in May 1997. The patent claims read-write
sensors for computer hard disk drive storage systems.
Hard disk drives store digital data in microscopic mag-
netic patterns on the surface of spinning platters, or
disks, inside the drive.
3                              MAGSIL CORP   v. HITACHI GLOBAL




     As shown in Fig. 1, the ’922 patent’s sensor uses a
quantum mechanical effect where electric current can
pass, or “tunnel,” from one electrode (e.g., 10) through a
thin insulating barrier layer (14) into a second electrode
(e.g., 12). ’922 patent col. 1 ll. 17-21, col. 3 l. 53-col. 4 l.
29.
     With two ferromagnetic electrodes, a tri-layer tunnel
junction requires the current flow to depend on the mag-
netization direction of the electrodes. The junction resis-
tance is higher when the magnetization direction of one
electrode (e.g., 28 in 10) is antiparallel (i.e., having the
opposite direction) to that of the other electrode (e.g., 28
in 12) and lower when the directions are parallel. Id. at
col. 1 ll. 28-31. Therefore, the tunnel junction resistance
changes with a change in magnetization direction. Id. at
col. 2 ll. 18-22.
    The ’922 patent claims both a method of manufactur-
ing a tri-layer tunnel junction and the junction itself. The
MAGSIL CORP   v. HITACHI GLOBAL                           4


asserted claims, however, only claim the tunnel junction
device. Claim 1 is representative of the two asserted
independent claims and reads:
     1. A device forming a junction having a resis-
     tance comprising:
     a first electrode having a first magnetization di-
     rection,
     a second electrode having a second magnetization
     direction, and
     an electrical insulator between the first and sec-
         ond electrodes, wherein applying a small
         magnitude of electromagnetic energy to the
         junction reverses at least one of the magneti-
         zation directions and causes a change in the
         resistance by at least 10% at room tem-
         perature.
Id. at col. 8 ll. 43-54 (emphasis added).
     According to the background section of the ’922 pat-
ent’s specification, scientists had known “for many years”
the basic theory underlying “tunnel resistance arising
from conduction electron spin polarization.” Id. at col. 2
ll. 3-5. Past efforts, however, failed to “produce an ade-
quate level of change in the tunneling resistance (ΔR/R)”
for practical applications. Id. at col. 2 ll. 5-8. At room
temperature, these past efforts had obtained only a 2.7%
change in resistance. Id. at col. 1 ll. 60-67. The ’922
invention, by contrast, achieved a “ten percent change in
the tunneling resistance with respect to magnetic field (H)
variation”; in some cases “as much as 11.8% change was
seen.” Id. at col. 2 ll. 44-51.
     The specification further teaches that
   [t]his increase in ΔR/R is believed to depend, inter
   alia, on a decrease in surface roughness, which
   apparently directly couples the two electrodes
   ferromagnetically. Also, the quality of the inter-
5                               MAGSIL CORP   v. HITACHI GLOBAL


    vening insulator between the [electrodes] is sig-
    nificantly improved over the prior art devices.
    This is believed to be important in keeping the
    surface integrity of the [electrodes].
Id. at col. 2 ll. 51-58. The asserted claims, however, do
not include the process steps of fabricating the device and
require neither smoother layers nor a specifically im-
proved insulator. The specification also explains manu-
facture of the tri-layer tunnel junction and ways to
incorporate this device into read-write sensor heads for
data storage. Id. at col. 3 l. 52-col. 4 l. 38, col. 6 l. 66-col.
8 l. 36.
     MagSil filed suit in December 2008 against several
defendants including Hitachi Global Storage Technolo-
gies, Inc., Hitachi America, Ltd., Hitachi Data Systems
Corporation, and Shenzhen Excelstor Technology, Ltd.
(collectively, “Hitachi”), alleging that their disk drive
products infringe the ’922 patent. The non-Hitachi defen-
dants have since been dismissed from the case. Chief
Judge Harvey Bartle III, sitting by designation from the
United States District Court for the Eastern District of
Pennsylvania, handled this litigation. After Markman
proceedings, the parties filed cross-motions for summary
judgment. The district court found the asserted claims
invalid as a matter of law for lack of enablement. The
district court entered its final judgment for Hitachi and
MagSil timely appealed to this court, which has jurisdic-
tion under 28 U.S.C. § 1295(a)(1).
                               II.
    This court reviews a district court’s grant of summary
judgment without deference, “drawing all reasonable
inferences in favor of the nonmovant.” Green Edge En-
ters., LLC v. Rubber Mulch Etc., LLC, 620 F.3d 1287,
1295 (Fed. Cir. 2010) (citing Anderson v. Liberty Lobby,
MAGSIL CORP   v. HITACHI GLOBAL                            6


Inc., 477 U.S. 242, 255 (1986)); see also Fed. R. Civ. P.
56(c). Enablement is a question of law based on underly-
ing factual findings. In re Wands, 858 F.2d 731, 735 (Fed.
Cir. 1988). A party must prove invalidity based on non-
enablement by clear and convincing evidence. Microsoft
Corp. v. i4i Ltd. P’ship, 131 S. Ct. 2238, 2242 (2011); AK
Steel Corp. v. Sollac, 344 F.3d 1234, 1238-39 (Fed. Cir.
2003). Thirty-five U.S.C. § 112 sets forth the enablement
requirement:
   [t]he specification shall contain a written descrip-
   tion of the invention, and the manner and process
   of making and using it, in such full, clear, concise,
   and exact terms as to enable any person skilled in
   the art to which it pertains, or with which it is
   most nearly connected, to make and use the same.

35 U.S.C. § 112, ¶ 1. “To be enabling, the specification of
a patent must teach those skilled in the art how to make
and use the full scope of the claimed invention without
‘undue experimentation.’” Genentech, Inc. v. Novo Nord-
isk, A/S, 108 F.3d 1361, 1365 (Fed. Cir. 1997) (quoting In
re Wright, 999 F.2d 1557, 1561 (Fed. Cir. 1993)). The
enablement determination proceeds as of the effective
filing date of the patent. Plant Genetic Sys., N.V. v.
DeKalb Genetics Corp., 315 F.3d 1335, 1339 (Fed. Cir.
2003).
    Enablement serves the dual function in the patent
system of ensuring adequate disclosure of the claimed
invention and of preventing claims broader than the
disclosed invention. See AK Steel, 344 F.3d at 1244. This
important doctrine prevents both inadequate disclosure of
an invention and overbroad claiming that might other-
wise attempt to cover more than was actually invented.
Thus, a patentee chooses broad claim language at the
peril of losing any claim that cannot be enabled across its
7                            MAGSIL CORP   v. HITACHI GLOBAL


full scope of coverage. “The scope of the claims must be
less than or equal to the scope of the enablement to en-
sure that the public knowledge is enriched by the patent
specification to a degree at least commensurate with the
scope of the claims.” Sitrick v. Dreamworks, LLC, 516
F.3d 993, 999 (Fed. Cir. 2008) (quoting Nat’l Recovery
Techs., Inc. v. Magnetic Separation Sys., Inc., 166 F.3d
1190, 1195-96 (Fed. Cir. 1999)); see also In re Fisher, 427
F.2d 833, 839 (CCPA 1970) (“[T]he scope of the claims
must bear a reasonable correlation to the scope of en-
ablement provided by the specification to persons of
ordinary skill in the art.”).
    The asserted claims of the ’922 patent broadly claim
any tri-layer tunnel junction device wherein “applying a
small magnitude of electromagnetic energy to the junction
… causes a change in the resistance by at least 10% at
room temperature.” ’922 patent at col. 8 ll. 50-54. The
district court construed the limitation “a change in resis-
tance of at least 10%” as:
    a change in resistance of at least 10% using the
    formula ΔR/R = (R1-R2)/R1, where ΔR/R represents
    the percent change in resistance, R1 is the resis-
    tance of the junction before the application of
    electromagnetic energy reverses at least one of the
    magnetization directions, and R2 is the resistance
    of the junction after the application of electro-
    magnetic energy and the resultant reversal of at
    least one of the magnetization directions.
MagSil Corp. v. Seagate Tech., No. 1:08-CV-0940, slip op.
at 2 (D. Del. Mar. 1, 2011). The district court further
found that the asserted claims cover “resistance changes
beyond 120% and up to infinity.” MagSil Corp., 764 F.
Supp. 2d at 680. Thus, the specification at the time of
MAGSIL CORP   v. HITACHI GLOBAL                           8


filing must teach one of ordinary skill in the art to fully
perform this method across that entire scope.
    The record shows that MagSil advocated for a broad
construction of this claim term. Its expert Dr. Murdock
testified that this term covers tunnel junctions with
resistive changes of 100% or more. Dr. Moodera, a named
inventor, also testified that a 1000% change falls within
the scope of the claims, despite that he had never made
such a tunnel junction.
    The specification—the disclosure available to show
the full scope of enablement—teaches that the inventors’
best efforts achieved a maximum change in resistance of
only 11.8% at room temperature. As the district court
noted, MagSil has “not disclaimed the asserted claims’
infinite scope in the area of resistive change.” Id. at 679.
Accordingly, this record and specification show that the
district court correctly discerned that the asserted claims
are not enabled. The ’922 patent application was filed in
March 1995. Hitachi has shown with clear and convinc-
ing evidence that one skilled in the art could not have
taken the disclosure in the specification regarding
“change in the resistance by at least 10% at room tem-
perature” and achieved a change in resistance in the full
scope of that term without undue experimentation.
     The specification must contain sufficient disclosure to
enable an ordinarily skilled artisan to make and use the
entire scope of the claimed invention at the time of filing.
Sitrick, 516 F.3d at 1000. Here, the specification teaches
that the fundamental science of the tunneling junction
was known “for many years,” but past efforts did not
produce effective use of the phenomenon. ’922 patent col.
2 ll. 3-8. The specification discloses a 1975 publication by
Michel Julliere that predicted an ideal tunnel junction
could yield around a 24% change in resistance. Yet, the
9                            MAGSIL CORP   v. HITACHI GLOBAL


specification teaches that twenty years later, when the
application was filed, the best achievement was an 11.8%
change. Named inventor Dr. Meservey also testified that
before the application was filed, he did not know how to
achieve a tunnel junction with greater than 20% change
in resistance.
    During prosecution of the ’922 patent, MagSil stated
that it had achieved resistive changes of 18% at this time
after the date of filing. During prosecution MagSil also
predicted still higher resistive changes because no clear
theoretical limit prevented achieving the highest possible
value of 100%. The inventors’ understanding during
prosecution that a 100% resistive change was an upper
limit is inconsistent with MagSil’s position at the time of
this case. During this litigation, MagSil’s expert Dr.
Murdock testified that a person of ordinary skill in the art
could work from the ’922 patent and make tunneling
junctions with a resistive change between 100% and 120%
without undue experimentation.
    Dr. Murdock’s aggressive view of the scope of this in-
vention, however, runs counter to his own testimony that
the first junction with this level of resistive change was
not developed until 2006 or 2007. It also does not explain
why it took some twelve years after the ’922 patent appli-
cation was filed to achieve these results. Dr. Murdock
also testified that experimentation on electrode metals
and tunnel barrier insulator materials, as well as on the
processes to make them, was needed to achieve these
results. He further acknowledged that even someone of
extraordinary skill in the art in 1995 could not have
predicted the exact process and materials needed for the
120% resistive change achieved over ten years later.
   Even if Dr. Murdock’s testimony could somehow over-
come the requirement that the enabling disclosure must
MAGSIL CORP   v. HITACHI GLOBAL                           10


appear in the specification at the time of filing, his asser-
tions also fail to reach the modern dimensions of this field
of invention. His testimony (suggesting a resistive change
between 100% and 120%) only reaches a lower-end of the
claimed scope. The invention claims resistive changes
from at least 10% up to infinity. Dr. Murdock admitted
that resistive change of 604% has now been achieved by
others, and the claim scope extends well beyond that
value as well. The ’922 patent specification does not
disclose working examples of tunnel junctions with resis-
tive changes of 20%, 120%, 604%, or 1000%. The named
inventors were not able to achieve even a 20% change a
year after filing the application in 1995, and 604% junc-
tions were not achieved until 2008.
     In sum, this field of art has advanced vastly after the
filing of the claimed invention. The specification contain-
ing these broad claims, however, does not contain suffi-
cient disclosure to present even a remote possibility that
an ordinarily skilled artisan could have achieved the
modern dimensions of this art. Thus, the specification
enabled a marginal advance over the prior art, but did not
enable at the time of filing a tunnel junction of resistive
changes reaching even up to 20%, let alone the more
recent achievements above 600%.
     The trial court’s finding of an enablement deficiency
falls squarely within this court’s precedent. See Fisher,
427 F.2d 833. In Fisher, the patent application was
directed to a system for production of substances contain-
ing adrenocorticotropic hormone (ACTH) that were suit-
able for injection into humans for adrenal gland
stimulation. 427 F.2d at 834. The claims recited a po-
tency of “at least 1 International Unit of ACTH per milli-
gram,” and the specification disclosed that previous
experiments yielded compounds with a maximum potency
of 50% or 0.5 International Units (“IUs”). Id. The patent
11                            MAGSIL CORP   v. HITACHI GLOBAL


application, however, only disclosed compounds with
ACTH potencies of between 111% and 230%, or 1.11 and
2.3 IUs per milligram. Id. The issue presented was:
     whether an inventor who is the first to achieve a
     potency of greater than 1.0 for certain types of
     compositions, which potency was long desired be-
     cause of its beneficial effect on humans, should be
     allowed to dominate all such compositions having
     potencies greater than 1.0, including future com-
     positions having potencies far in excess of those
     obtainable from his teachings plus ordinary skill.
Id. at 839. The claims were not patentable because the
specification did not enable ACTH potencies much greater
than 2.3 IUs, when “at least 1” was claimed. Id. at 839.
    Here, the claim term “change in the resistance by at
least 10%” is very similar to the “open-ended” term in
Fisher because it has a lower threshold, but not an upper
limit. The asserted claims of the ’922 patent cover resis-
tive changes from 10% up to infinity, while the ’922
patent specification only discloses enough information to
achieve an 11.8% resistive change. The specification
discloses that artisans hoped to achieve values of around
24%, but had not done so. During prosecution MagSil
believed that the highest possible resistive change was
100%. Yet, the claims covered changes far above 20% or
100% even when the inventors could not explain any way
to achieve these levels. As MagSil’s expert Dr. Murdock
testified, since 1995 when the specification was filed,
resistive changes now stretch up to above 600%.
    The open claim language chosen by the inventors does
not grant them any forgiveness on the scope of required
enablement. Open claim language, such as the word
“comprising” as a transition from the preamble to the
body of a claim, “signals that the entire claim is presump-
MAGSIL CORP   v. HITACHI GLOBAL                          12


tively open-ended.” Gillette Co. v. Energizer Holdings,
Inc., 405 F.3d 1367, 1371 (Fed. Cir. 2005). “The transition
‘comprising’ creates a presumption that the recited ele-
ments are only a part of the device, that the claim does
not exclude additional, unrecited elements.” Crystal
Semiconductor Corp. v. TriTech Microelectronics Int’l,
Inc., 246 F.3d 1336, 1348 (Fed. Cir. 2001). MagSil seeks
some easing of the enablement requirement by using this
language in the asserted claims. To support its argu-
ment, MagSil refers to this court’s decision in Gillette.
    In Gillette, the patentee claimed “[a] safety razor
blade unit comprising … a group of first, second, and
third blades.” 405 F.3d at 1369. In that preliminary
injunction case, this court noted that the claim used “the
‘open’ claim terms ‘comprising’ and ‘group of,’ in addition
to other language, to encompass subject matter beyond a
razor with only three blades.” ld. at 1371. This court
looked to the claim language, specification, and prosecu-
tion history to find that the claim covered a razor with
four blades. ld. at 1371-72. This court also noted that the
open language of the claim “embraces technology that
may add features to devices otherwise within the claim
definition.” ld. at 1371.
    MagSil contends that its open-ended threshold recita-
tion of “at least 10%,” which when construed does not
have an upper limit, is equivalent to Gillette’s open-
language “comprising” recitation.       Therefore, MagSil
argues, if the “at least 10%” recitation is construed to not
have an upper limit, then the “comprising” recitation as
found in Gillette should also be construed to include every
conceivable number of blades, up to infinity, which would
not have been enabled. In the first place, enablement was
not an issue in Gillette. Moreover, the safety razor tech-
nology and the very fact-specific distinctions in that case
do not apply in this technology or case. In Gillette, for
13                           MAGSIL CORP   v. HITACHI GLOBAL


example, the open claim language entailed more than the
“comprising” term and the construction was aided by the
specification and prosecution history. In fact, the issue
concerned whether the claim language covered an em-
bodiment with more than one blade labeled as a “second
blade,” where the terms “first, second, and third” did not
specify the number of blades but specific characteristics of
blades in those categories. ld. at 1372-73. Thus, the
Gillette invention did not claim an infinite number of
blades but blades with three separate categories of char-
acteristics. Therefore, this case’s claim limitation extend-
ing to an open-ended range of values, which must be
present for infringement, is different from a preamble
recitation “comprising,” which does not exclude additional
features to devices otherwise within the narrower claim
definition. See id.
     The ’922 patent specification only enables an ordinar-
ily skilled artisan to achieve a small subset of the claimed
range. The record contains no showing that the knowl-
edge of that artisan would permit, at the time of filing,
achievement of the modern values above 600% without
undue experimentation, indeed without the nearly twelve
years of experimentation necessary to actually reach
those values. The enablement doctrine’s prevention of
over broad claims ensures that the patent system pre-
serves necessary incentives for follow-on or improvement
inventions. In this case, for instance, many additional
inventions and advances were necessary to take this
technology from a 20% resistance change to the over 600%
change in present data storage systems. Moreover this
technology area will continue to profit from inventive
contributions. Enablement operates to ensure fulsome
protection and thus “enable” these upcoming advances.
    MagSil’s difficulty in enabling the asserted claims is a
problem of its own making. See Liebel-Flarsheim Co. v.
MAGSIL CORP   v. HITACHI GLOBAL                            14


Medrad, Inc., 481 F.3d 1371, 1380 (Fed. Cir. 2007) (“The
irony of this situation is that Liebel successfully pressed
to have its claims include a jacketless system, but, having
won that battle, it then had to show that such a claim was
fully enabled, a challenge it could not meet.”) This court
holds that the asserted claims are invalid for lack of
enablement because their broad scope is not reasonably
supported by the scope of enablement in the specification.
See Fisher, 427 F.2d at 839. MagSil did not fully enable
its broad claim scope. Therefore, it cannot claim an
exclusive right to exclude later tri-layer tunnel junctions
that greatly exceed a 10% resistive change. Id.
                             III.
    The district court entered summary judgment of non-
infringement of the asserted claims after finding them
invalid for lack of enablement. Hitachi’s disk drive prod-
ucts do not infringe the asserted claims because “[t]here
can be no infringement of claims deemed to be invalid.”
Marrin v. Griffin, 599 F.3d 1290, 1295 (Fed. Cir. 2010).
     For the forgoing reasons, this court affirms the dis-
trict court’s finding that claims 1-5, 23-26, and 28 of the
’922 patent are invalid for lack of enablement. Accord-
ingly, this court also affirms the district court’s finding of
non-infringement.
                        AFFIRMED
