SunPower Corporation v. PanelClaw Inc.

Filing 88

MEMORANDUM OPINION. Signed by Judge Mary Pat Thynge on 4/1/16. (cak)

IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF DELAWARE
SUNPOWER CORPORATION,
Plaintiff,
v.
PANELCLAW, INC.,
Defendant.

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C. A. No. 12-1633-MPT

MEMORANDUM
I.

INTRODUCTION
This is a patent case. On December 3, 2012, SunPower Corporation

(“SunPower”) filed suit alleging PanelClaw, Inc. (“PanelClaw”) infringes U.S. Patent Nos.
5,505,788 (“the ‘788 patent”) and RE38,988 (“the ‘988 patent”).1 SunPower amended
its complaint on January 24, 2013, and again on April 15, 2013.2 PanelClaw filed its
answer and counterclaims to the Second Amended Complaint on May 29, 2013.3
SunPower answered PanelClaw’s counterclaims on June 21, 2013.4 Pursuant to the
court’s October 2, 2013 Order, SunPower provided its preliminary claim charts to
PanelClaw on October 18, 2013.5 PanelClaw then filed petitions for inter partes review
(“IPR”) of the asserted patents and the court stayed the case pending resolution of the
IPRs on May 16, 2014.6
1

D.I. 1.
D.I. 5 (First Amended Complaint); D.I. 16 (Second Amended Complaint).
3
D.I. 18.
4
D.I. 19.
5
D.I. 24.
6
D.I. 31; D.I. 43.
2

On June 30, 2014, the United States Patent and Trademark Office (“USPTO”)
denied institution of IPR of the claims of the ‘788 patent7 (including currently asserted
claims 1-5), denied institution of IPR with respect to currently asserted claims 17, 18,
36, 38-40, 58, 59, 61-63, 65, 66, 71-73, and 76 of the ‘988 patent, and granted
institution of IPR with respect to claims 1, 55, 56, 78, and 79 of the ‘988 patent.8 On
April 3, 2015, the USPTO issued a Final Written Decision on the ‘988 patent finding
claims 1, 55, 56, 78, and 79 unpatentable due to anticipation.9 The court then lifted the
stay on July 13, 2015.10 On September 11, 2015, the parties filed a request consenting
to this judge’s jurisdiction in this case for all purposes, including trial and final
judgement, which was granted on September 16, 2015.11 The court entered a
Scheduling Order on October 23, 2015.12 On November 2, 2015, the parties submitted
a joint stipulation agreeing to PanelClaw filing an early motion for summary judgement
“focused solely on the limited issues identified by Defendant in the Joint Status Report
(D.I. 46 at 3-5)” which the court permitted on November 4, 2015.13 Currently before the
court is PanelClaw’s motion for summary judgement of non-infringement and invalidity.14
PanelClaw asserts non-infringement of the asserted claims of the ‘788 patent, and that
the asserted claims of the ‘988 patent are invalid due to indefiniteness, lack of
enablement, and failure to meet the written description requirement under 35 U.S.C.
7

D.I. 71, Ex. C.
D.I. 74, Ex. 1.
9
D.I. 71, Ex. G.
10
D.I. 45.
11
D.I. 49; D.I. 50.
12
D.I. 57.
13
D.I. 63.
14
D.I. 69.
8

2

§ 112, and/or under 35 U.S.C. § 101 as inoperative and lacking utility.15
II.

BACKGROUND
SunPower is a publically traded company that has been developing solar

technologies since the 1980s. It describes itself as a global leader in developing highefficiency solar solutions for private residences, businesses, utilities, and city, county,
state, and federal government customers.16 Founded in 2007, PanelClaw is a privately
owned company headquartered in North Andover, Massachusetts.17 PanelClaw does
not develop, sell, or install solar panel assemblies.18 Instead, its accused products are
mounting solutions that consist of a support for a solar panel, a “claw” for securing the
solar panel to the support, and, in some cases, a wind deflector.19 PanelClaw’s
customers purchase the components of its mounting systems to be assembled with
panels and equipment supplied by others.20
SunPower maintains that within the last several years, PanelClaw has released a
series of products that compete with SunPower’s T5 and T10 product lines which
embody the inventions of the asserted claims.21 Specifically, SunPower asserts
PanelClaw’s Polar Bear and Grizzly Bear products compete directly with SunPower’s T5
and T10 product lines in the market for installation of photovoltaic systems on
commercial building roofs.22
15

D.I. 70 at 10-15.
D.I. 38 at ¶ 4; D.I. 71, Ex. L.
17
D.I. 71, Ex. K.
18
D.I. 13, Ex. A at ¶¶ 4-5.
19
D.I. 71, Ex. J at Ex. A, p. 4 & Ex. B, p. 4.
20
D.I. 13, Ex. A at ¶ 6.
21
D.I. 38 at ¶¶ 12-13.
22
Id.
16

3

‘788 patent, titled “Thermally Regulated Photovoltaic Roofing Assembly,” was
filed in 1994, issued in 1996, and expired in 2012. The invention “generally relates to a
photovoltaic roofing assembly, and in particular to a photovoltaic roofing assembly
which can regulate the temperatures experienced by the solar cells and requires no roof
penetrations for hold-down to the roof surface.”23 The Abstract of the ‘788 patent
recites:
A photovoltaic roofing assembly comprises a roofing membrane (102), a
plurality of photovoltaic modules (104, 106, 108, 110) disposed as a layer
on top of the roofing membrane (102), and a plurality of pre-formed
spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are
respectively disposed below the plurality of photovoltaic modules (104,
106, 108, 110) and integral therewith, or fixed thereto. Spacers (112, 114,
116, 118, 120, 122) are disposed on top of roofing membrane (102).
Membrane (102) is supported on conventional roof framing, and attached
thereto by conventional methods. In an alternative embodiment, the
roofing assembly may have a tapered profile for orienting modules (204,
206, 208, 210) in a direction of increased sun exposure. Other
embodiments include the use of phase change material for temperature
regulation, and incorporating an insulation block into the assembly as a
means of spacing and of building thermal control. Such construction
results in a simple, readily assembled roofing assembly which regulates
the temperature of the photovoltaic module and roofing membrane and
avoids the need for roofing penetrations for hold-down to the building
rooftop. Photovoltaic modules (104, 106, 108, 110) serve the purpose of
electric generator, and in addition, the multiple purposes of ballast, UV
block, and weather protector for the insulation block and roofing
membrane below. A fluid convects within the passageways created by the
spacers, transferring heat from the backside of the photovoltaic modules.
Rainwater drains through the joints between the integral modules, onto
and over the roofing membrane below.24
The ‘988 patent, titled “Lightweight, Self-Ballasting Photovoltaic Roofing
Assembly,” a re-issue of U.S. Patent No. 5,746,839 issued in 1998, was filed in 2003,

23
24

‘788 patent, 1:6-10.
‘788 patent, Abstract.
4

issued in 2006, and expires in early 2016. The invention “generally relates to a
photovoltaic roofing assembly, and in particular to a lightweight photovoltaic roofing
assembly requiring no roofing penetrations and which resists wind up-lift due to
specialized component geometry and by acting as an integral assembly.”25 The
Abstract of the ‘988 patent recites:
A photovoltaic roofing assembly comprises a roofing membrane (102), a
plurality of photovoltaic modules (104, 106, 108) disposed as a layer on
top of the roofing membrane (102), and a plurality of pre-formed spacers,
pedestals or supports (112, 114, 116, 118, 120, 122) which are
respectively disposed below the plurality of photovoltaic modules (104,
106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116,
118, 120, 122) are disposed on top of roofing membrane (102).
Membrane (102) is supported on conventional roof framing, and attached
thereto by conventional methods. In an alternative embodiment, the
roofing assembly may have insulation block (322) below the spacers (314,
314', 315, 315‘). The geometry of the preformed spacers (112, 114, 116,
118, 120, 122, 314, 314‘, 315, 315') is such that wind tunnel testing has
shown its maximum effectiveness in reducing net forces of wind uplift on
the overall assembly. Such construction results in a simple, lightweight,
self-ballasting, readily assembled roofing assembly which resists the
forces of wind uplift using no roofing penetrations.26
III.

GOVERNING LAW
Summary judgment is appropriate “if the movant shows that there is no genuine

dispute as to any material fact and the movant is entitled to judgment as a matter of
law.”27 This standard is applicable to all types of cases, including patent cases.28 The
movant bears the burden of establishing the lack of a genuinely disputed material fact
by demonstrating “that there is an absence of evidence to support the nonmoving

25

‘988 patent, 1:22-26.
‘988 patent, Abstract.
27
FED. R. CIV. P. 56(a).
28
Johnston v. IVAC Corp., 885 F.2d 1574, 1576-77 (Fed. Cir. 1989).
26

5

party’s case.”29 “Facts that could alter the outcome are ‘material,’ and disputes are
‘genuine’ if evidence exists from which a rational person could conclude that the position
of the person with the burden of proof on the disputed issue is correct.”30 “Where the
record taken as a whole could not lead a rational trier of fact to find for the non-moving
party, there is no genuine issue for trial.”31
Infringement is a question of fact that must be proven by a preponderance of the
evidence.32 “Determining literal infringement is a two step process: the ‘proper
construction of the asserted claim and a determination of whether the claim as properly
construed reads on the accused product or method.’”33
“Because a patent is presumed to be valid, the evidentiary burden to show facts
supporting a conclusion of invalidity is one of clear and convincing evidence.”34
“[A] patent is invalid for indefiniteness if its claims, read in light of the
specification delineating the patent, and the prosecution history, fail to inform, with
reasonable certainty, those skilled in the art about the scope of the invention.”35 “[A]
claim must be ‘sufficiently definite to inform the public of the bounds of the protected

29

Celotex Corp. v. Catrett, 477 U.S. 317, 325 (1986).
Horowitz v. Fed. Kemper Life Assurance Co., 57 F.3d 300, 302 n.1 (3d
Cir.1995) (internal citations omitted).
31
Matsushita Elec. Indus. Co. v. Zenith Radio Corp., 475 U.S. 574, 587 (1986)
(internal quotations omitted).
32
See, e.g., Cross Med. Prods. Inc. v. Medtronic Sofamor Danek, Inc., 424 F.3d
1293, 1302, 1310 (Fed. Cir. 2005).
33
ActiveVideo Networks, Inc. v. Verizon Commc’ns, Inc., 694 F.3d 1312, 1319
(Fed. Cir. 2012) (quoting Georgia-Pacific Corp. v. U.S. Gypsum Co., 195 F.3d 1322,
1330 (Fed. Cir. 1999)).
34
Young v. Lumenis, Inc., 492 F.3d 1336, 1345 (Fed. Cir. 2007) (citing AK Steel
Corp. v. Sollac & Ugine, 344 F.3d 1234, 1338-39 (Fed. Cir. 2003)).
35
Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2122 (2014).
30

6

invention, i.e., what subject matter is covered by the exclusive rights of the patent.’”36
Enablement is a question of law . . . . To satisfy section 112 of the 1952
Patent Act, the specification must enable a person of ordinary skill in the
art to make and use the invention. This requirement is met when at the
time of filing the application one skilled in the art, having read the
specification, could practice the invention without undue experimentation.
Whether undue experimentation is required is not a single, simple factual
determination, but rather is a conclusion reached by weighing many
factual considerations.37
The written description inquiry is a question of fact.38 To comply with that
requirement:
the description must clearly allow persons of ordinary skill in the art to
recognize that [the inventor] invented what is claimed. In other words, the
test for sufficiency is whether the disclosure of the application relied upon
reasonably conveys to those skilled in the art that the inventor had
possession of the claimed subject matter asa of the filing date.39
Although “[c]ompliance with the written description requirement is a question of fact [it]
is amenable to summary judgment in cases where no reasonable fact finder could
return a verdict for the non-moving party.”40
IV.

DISCUSSION
SunPower alleges claims 1-5 of the ‘788 patent are infringed by PanelClaw’s

Grizzly Bear and Polar Bear products.41 Claim 1 is the only asserted independent claim.

36

Ancora Techs., Inc. v. Apple, Inc., 744 F.3d 732, 737 (Fed. Cir. 2014) (quoting
Halliburton Energy Servs., Inc. v. M–I LLC, 514 F.3d 1244, 1249 (Fed. Cir. 2008)).
37
Cephalon, Inc. v. Watson Pharms., Inc., 707 F.3d 1330, 1336 (Fed. Cir. 2013)
(citations, internal quotation marks, and footnote omitted).
38
Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010).
39
Id.
40
PowerOasis, Inc. v. T-Mobile USA, Inc., 522 F.3d 1299, 1307 (Fed. Cir. 2008)
(citing Invitrogen Corp. v. Clonetech Labs., Inc., 429 F.3d 1052, 1072-73 (Fed. Cir.
2005)).
41
D.I. 16 at ¶¶ 18-25.
7

Claims 2-4 are dependent or multi-dependent from claim 1. Claim 1 recites:
A photovoltaic roofing assembly, comprising:
a roofing membrane;
a plurality of photovoltaic modules disposed as a layer on top of
said roofing membrane, and
means for regulating the temperature of said photovoltaic
modules.42
PanelClaw bases its non-infringement argument on the construction of phrase
“disposed as a layer” on a roof given by the Patent Trial and Appeal Board (“PTAB”)
during the IPR for the ’788 patent. In that IPR, PanelClaw submitted prior art, including
references “Brown” and “Stiebel,” arguing that these references anticipate the asserted
claims of the ‘788 patent.43 Those references show rooftop mounted solar panel
assemblies with solar panels mounted at an angle on a roof and gaps between the solar
panels.44 In response, SunPower argued “a person of ordinary skill in the art would
have readily understood that ‘a plurality of photovoltaic modules disposed as a layer on
top of said roofing membrane’ . . . means that the photovoltaic modules . . . are
arranged as an overlying surface on top of the roofing membrane.”45 The PTAB agreed
with SunPower and construed “as a layer on top of said roofing membrane” to mean
“that the photovoltaic modules or integral units, as the case may be, are arranged as an
overlying surface on top of the roofing membrane.”46
42

‘788 patent, claim 1.
D.I. 71, Ex. C (PTAB Decision) at 11-15.
44
D.I. 70 at 5.
45
D.I. 71, Ex. B (Patent Owner SunPower Corporation’s Preliminary Response)
at 17, 23.
46
Id., Ex. C at 8.
43

8

Based on that construction, the PTAB determined the Brown and Stiebel
references did not disclose that requirement. The PTAB found “each row of solar
panels in Brown is at an incline to the roof, such that a large gap exists between
successive rows. They do not provide an overlying surface to the roofing membrane”47
and “[b]ecause the panels [disclosed in Stiebel] are inclined, a gap exists between
successive solar panel panels, precluding the formation of such an overlying surface.”48
PanelClaw now requests that the court adopt the PTAB’s construction of “as a
layer on top of said roofing membrane” as “that the photovoltaic modules or integral
units, as the case may be, are arranged as an overlying surface on top of the roofing
membrane.”49 It maintains this construction is consistent with the specification and
SunPower’s arguments to the PTAB.50 It also asserts adoption of the PTAB’s
construction of that phrase is appropriate because that construction was based on the
same type of interpretation conducted by the courts.51 During the IPR, the PTAB
rejected PanelClaw’s assertion that the claims should be given their broadest
reasonable construction pursuant to 37 C.F.R. § 42.100(b).52 Because the ‘788 patent
47

Id., Ex. C at 12.
Id., Ex. C at 15; see also id., Ex. B at 19 (SunPower arguing “Brown’s panels
are not arranged as an overlying surface on top [of] a roofing membrane and therefore
does not teach or disclose ‘a plurality of photovoltaic modules disposed as a layer on
top of said roofing membrane’ . . . .”).
49
D.I. 70 at 7.
50
Id. PanelClaw also contends because SunPower’s argument before the PTAB
was successful, it is estopped from taking a different position now. Id. The court
disagrees with that contention. See adidas AG v. Under Armour, Inc., C.A. No. 14-130GMS, D.I. 201 (Order Denying Defendants’ Motion to Modify the Court’s Claim
Construction Order) at 2 n.1. (D. Del. Dec. 15, 2015) (“The PTAB’s choice not to
institute an IPR is not the type of adjudication that leads to issue preclusion.”).
51
D.I. 70 at 7 n.1.
52
D.I. 71, Ex. C at 6.
48

9

is expired, the PTAB found PanelClaw’s reliance on that regulation misplaced as the
rule pertains only to claims “in an unexpired patent.”53 “‘[T]he Board’s review of the
claims of an expired patent is similar to that of a district court’s review.’”54 In the context
of construing the claims of an expired patent, the PTAB generally gives claim terms
their ordinary and customary meaning, as understood by a person of ordinary skill in the
art, at the time of the invention, taking into consideration the language of the claims, the
specification, and the prosecution history of record because the expired claims are not
subject to amendment.55
According to PanelClaw, under the PTAB’s construction its accused products
cannot infringe because, when assembled with photovoltaic panels, those products
support the panels at an angle with gaps of exposed roof between rows.56 It argues that
as with Brown and Stiebel, the gaps between successive rows of panels in the
assembled PanelClaw system mean there is no overlying surface and no “layer on top
of said roofing membrane,” which it insists is required by all asserted claims.57
PanelClaw asserts, therefore, for the exact same reason the PTAB found these claims
not anticipated by Brown and Stiebel, they cannot be infringed by PanelClaw’s

53

Id., Ex. C at 6-7 (quoting 37 C.F.R. § 42.100(b) (“A claim in an unexpired
patent shall be given its broadest reasonable construction in light of the specification of
the patent in which it appears.”)).
54
Id., Ex. C at 7 (alteration in original) (quoting In re Rambus, Inc., 694 F.3d 42,
46 (Fed. Cir. 2012)).
55
Id., Ex. C at 7 (citing Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 (Fed. Cir.
2005) (en banc)).
56
D.I. 70 at 7 (citing D.I. 71, Ex. J at Ex. K, p. 1 (PanelClaw advertising material
picturing its Grizzly Bear product having gaps between rows of panels)).
57
Id.
10

products,58 and concludes that SunPower’s argument before the PTAB to obtain a
construction of “disposed as a layer” that distinguished the claims from Brown and
Stiebel, also distinguishes the claims from PanelClaw’s products.59
SunPower characterizes PanelClaw’s opening brief is devoid of evidentiary
support in asking the court to make findings on disputed factual issues, such as noninfringement.60 It notes fact discovery is in the very early stages and expert discovery is
a year away.61 Moreover, it contends PanelClaw’s arguments are inextricably
intertwined with claim construction, which the court has not yet undertaken.62
Therefore, SunPower maintains the issues raised by PanelClaw are not appropriate for
summary judgment.63
SunPower states several genuine issues of material fact preclude summary
judgment of non-infringement of the ‘788 patent. It contends that rather than engaging
in the proper legal infringement analysis requiring the accused products to be compared
to properly construed claims, PanelClaw stretches and distorts the holding of the PTAB
in denying institution of IPR, performs a legally flawed non-infringement analysis, and
presents the court with nothing more than attorney argument.64
SunPower argues PanelClaw’s assertion that the PTAB denied the IPR because
“the ‘Brown’ and ‘Stiebel’ references were inclined, with gaps between the panels, such

58

Id. at 7-8.
Id. at 8.
60
D.I. 73 at 1.
61
Id.
62
Id. A claim construction hearing is currently scheduled for June 3, 2016.
63
Id.
64
Id. at 6.
59

11

that they did not form an overlying surface like that described in the patent” is
inaccurate.65 The PTAB explained that PanelClaw failed to identify the requisite
corresponding structure in its IPR petition for the “means for regulating the temperature
of said photovoltaic modules” in independent claim 1.66 Due to that failure, the PTAB
denied the IPR petition as to claims 1-5 “for this reason alone.”67 The PTAB did,
however, note that although it denied the IPR for that reason, it stated “we also address
another deficiency common to claims 1-5," i.e., the lack of disclosure of solar panels
arranged as an overlying surface on top of a roof in the Brown and Stiebel references
because of gaps between rows of panels.68 It is the construction by the PTAB of the
phrase at issue on which PanelClaw bases its non-infringement argument.
SunPower states that the court is not bound by the PTAB’s construction of the
phrase “disposed as a layer.” Although SunPower’s statement is correct,69 it is not
improper for the court to take the PTAB’s claim construction into consideration,70
65

Id. at 7 (quoting D.I. 70 at 6).
D.I. 71, Ex. C at 9-10.
67
Id., Ex. C at 10. SunPower also criticizes PanelClaw for not addressing the
means-plus-function limitation in its opening brief. That criticism is misplaced. “To
prove literal infringement, a plaintiff must show that the accused device contains each
and every limitation of the asserted claims.” Presidio Components, Inc. v. Amer. Tech.
Ceramics Corp., 702 F.3d 1351, 1358 (Fed. Cir. 2012) (citing Uniloc USA, Inc. v.
Microsoft Corp., 632 F.3d 1292, 1301 (Fed. Cir. 2011)). PanelClaw need not discuss
the means-plus-function limitation because, as noted above, its summary judgment
motion rests on the argument that the accused products do not meet the “disposed as a
layer” element of the asserted claims.
68
D.I. 71, Ex. C at 12 n.7, 15 n.8.
69
adidas AG v. Under Armour, Inc., C.A. No. 14-130-GMS, D.I. 201 at 2 n.1. (D.
Del. Dec. 15, 2015). (“The court is not bound by a preliminary claim construction used
by the PTAB for the limited purpose of denying an IPR request.”).
70
Centrak, Inc. v. Sonitor Techs., Inc., C.A. No. 14-183-RGA, 2015 WL 9595999,
at *4 (D. Del. Dec. 30, 2015) (“[W]hile not controlling, I find the PTAB’s construction of
this term in its decision not to institute inter partes review of [the] ‘909 patent to be well66

12

particularly where that construction was “similar to that of a district court’s review.”71
Here, the court finds the PTAB’s construction to be well-reasoned and
persuasive. First, SunPower, itself, argued to the PTAB that:
Brown’s solar panels are substantially vertical with large open spaces between
the panels. Accordingly, Brown’s panels are not arranged as an overlying
surface on top on a roofing membrane and therefore, Brown does not teach or
disclose “a plurality of photovoltaic modules disposed as a layer on top of said
roofing membrane” . . . .72
*****
Stiebel does not disclose that its solar panels are disposed as a layer.
Rather, Stiebel teaches that its solar panels are substantially upright with
a large space between two adjoining solar panels. Accordingly, Stiebel’s
panels are not arranged as an overlying surface on top [of] a roofing
membrane and therefore, Stiebel does not teach or disclose “a plurality of
photovoltaic modules disposed as a layer on top of said roofing
membrane” . . . .73
The PTAB agreed with SunPower’s proposed construction and noted it was
supported by the specification’s statement that “‘[t]he photovoltaic module performs the
multiple functions normally provided by a roofing paver, including ballast, UV protection,
and weather protection for the membrane and insulation layers below.’”74 Referencing

reasoned and persuasive.”).
71
D.I. 71, Ex. C at 6-7. SunPower contends that the PTAB’s discussion of the
prior art was in the context of invalidity, not infringement. D.I. 73 at 7. The PTAB’s
construction of “disposed as a layer” was in the context of claim construction, in which it
analyzed SunPower’s arguments in favor of its proposed construction, the specification,
and the construction from prior litigation involving the ‘788 patent. After accepting
SunPower’s proposed construction, the PTAB then applied that construction to the prior
art references in its separate invalidity analysis.
72
D.I. 71, Ex. B at 18 (citation omitted).
73
Id., Ex. B at 24 (citation omitted).
74
Id., Ex. C at 8 (quoting ‘788 patent, 4:3-7 (Summary of the Invention)).
SunPower had directed the PTAB to that specification language in support of its
proposed construction. Id., Ex. B at 17.
13

Figure 9 of the ‘788 patent, the PTAB noted “[t]he specification also illustrates an array
of photovoltaic modules as an overlying surface on top of large section of a roofing
membrane.”75 Notably, the ‘788 patent was asserted in prior litigation by SunPower. In
that case, the court construed “modules disposed as a layer on top of said roofing
membrane” to mean “modules that are arranged in a manner that provides coverage of
a surface.”76 The PTAB cited that construction as also being consistent with the
construction suggested by SunPower and adopted by the PTAB.77 The court, therefore,
adopts the PTAB’s construction of “as a layer on top of said roofing membrane” as “that
the photovoltaic modules or integral units, as the case may be, are arranged as an
overlying surface on top of the roofing membrane.”
SunPower argues that PanelClaw asks the court to improperly compare an
annotated image of one of the accused products, not to the asserted claims, but to two
prior art assemblies asserted in the IPR.78 SunPower notes a comparison of accused
products to the prior art cannot be the basis of a defense to infringement.79 The court
disagrees that PanelClaw is asking the court to make such a comparison. PanelClaw is
asking the court to find that rooftop mounted solar panel assemblies having large gaps
with exposed roof are not “disposed as a layer” as required by the asserted claims.80
75

Id., Ex. C at 8.
SunPower Corp. v. Sunlink Corp., No. CV 08-2807 SBA, 2009 WL 2996724, at
*1 (N.D. Cal. Mar. 16, 2009) (the “Sunlink case”).
77
D.I. 71, Ex. C at 8.
78
D.I. 73 at 1, 7.
79
See Tate Access Floors, Inc. v. Interface Architectural Res., Inc., 279 F.3d
1357, 1365 (Fed. Cir. 2002) (explaining there is no “practicing the prior art” defense to
infringement); Ecolab, Inc. v. Paraclipse, Inc., 285 F.3d 1362, 1377 (Fed. Cir. 2002)
(“‘[P]racticing the prior art’ is not a defense to literal infringement.”).
80
D.I. 77 at 1.
76

14

Having adopted the PTAB’s construction, the court determines that PanelClaw’s
accused products do not infringe the ‘788 patent. The evidence PanelClaw relies on to
demonstrate its accused products do not meet the “disposed as a layer” limitation
comes from SunPower’s own infringement contentions. In its opening brief, PanelClaw
cites exhibit K of those contentions, which shows its Grizzly Bear product having rows of
panels with significant gaps between them leaving the roof exposed in those gaps.81
Other exhibits to SunPower’s contentions similarly show large gaps between the solar
panels of PanelClaw’s accused Polar Bear products.82 With such an arrangement, the
photovoltaic modules cannot “perform the multiple functions normally provided by a
roofing paver, including ballast, UV protection, and weather protection for the
membrane and insulation layers below,”83 and do not meet the requirement that “the
photovoltaic modules or integral units, as the case may be, are arranged as an
overlying surface on top of the roofing membrane.” Consequently, the court grants
PanelClaw’s motion for summary judgement of non-infringement of the ‘788 patent.
81

D.I. 70 at 7 (citing D.I. 71, Ex. J at Ex. K, p.1); see also D.I. 71, Ex. C at 1 (also
showing a large gap between Grizzly Bear solar panels). SunPower cites Figures 1a-c
and 2a-c as showing gaps between rows of photovoltaic panels. D.I. 73 at 9. Those
figures do show small gaps between the panels. In each of those illustrations, however,
the spacers, pedestals, or supports under the panels extend across whatever gap
exists, thus leaving the roof membrane unexposed. Despite any gaps illustrated in
those drawings, it is clear that PanelClaw’s products do not meet the “disposed as a
layer” limitation. SunPower also cites the specification’s description of the layer below
the modules as “semi-continuous.” Id. (citing ‘788 patent, 6:9-23). That passage, in
part, reads “[a] semi-continuous spacial layer is created below photovoltaic modules
104, 106, 108, 110 which enables the convection of a fluid, preferably air, through
passageways created by the spacers.” ‘788 patent, 6:18-22. That passage describes
the air gap (i.e. spacial layer) between the modules and the roof; it does not describe
the modules being semi-continuous.
82
See D.I. 71, Ex. J at Ex. E, p.1; id., Ex. J at Ex. F p.1
83
‘788 patent, 4:3-7.
15

SunPower alleges PanelClaw’s Grizzly Bear and Polar Bear products infringe
claims 17, 18, 36, 38-40, 58, 59, 61-63, 65, 66, 71-73, and 76 of the ‘988.84
Representative independent claim 36 recites:
A photovoltaic roofing assembly comprising:
a plurality of photovoltaic assemblies, each said photovoltaic
assembly comprising:
a photovoltaic module having upper, lower, and lateral sides
and having upper and lower surfaces; and
a variable-height spacer secured to the lower surface of the
photovoltaic module so to orient said photovoltaic module at
an angle with said lateral sides extending downwardly from
said upper side to said lower side, said angle being about
5E-30E from horizontal;
said spacer sized and configured to define:
a tapered open region beneath said lower surface; and
access openings along said upper and lower sides fluidly
coupling said open region to said upper surface;
whereby wind uplift forces are resisted when said
photovoltaic assembly is mounted to a support surface; and
means for interengaging adjacent photovoltaic assemblies into an
array of photovoltaic assemblies, said array defining a perimeter.85
PanelClaw argues the asserted claims of the ‘988 patent are invalid as indefinite,
for failure to meet the enablement and written description requirements, and/or lack of
operability.86 Invalidity must be demonstrated by clear and convincing evidence.87
84

D.I. 16 at ¶¶ 26-36.
‘988 patent, claim 36.
86
D.I. 70 at 2-3.
87
Young v. Lumenis, Inc., 492 F.3d 1336, 1345 (Fed. Cir. 2007) (citing AK Steel
Corp. v. Sollac & Ugine, 344 F.3d 1234, 1328-39 (Fed. Cir. 2003)).
85

16

Each of the asserted claims of the ‘988 patent recites a “photovoltaic assembly”
which PanelClaw notes comprises a photovoltaic module and a spacer secured to the
bottom of the photovoltaic module that creates an “open region” underneath the module
and “access openings.”88 Each of the claims also include the language “whereby wind
uplift forces are resisted when said photovoltaic assembly is mounted to a support
surface” (“the Whereby Clause”).89
PanelClaw bases its indefiniteness argument on the Whereby Clause. In
support, it cites certain statements and conclusions the PTAB made in its ‘988 patent
IPR decision, and the testimony of SunPower’s expert, Theodore Stathopoulos, Ph.D.,
as part of that IPR. PanelClaw maintains, however, the asserted claims are indefinite
regardless of how the Whereby Clause is construed because it argues that clause has
no discernible scope as every object on Earth resists some amount of wind uplift
forces.90 PanelClaw argues there is nothing in the claims that suggest (i) the
circumstances under which “wind uplift forces” are resisted, (ii) what in particular causes
that resistance or (iii) how much resistance (however that might be measured) would be
sufficient to meet the limitation.91
In the ‘988 patent IPR, the PTAB determined claims 1, 55, 56, 78, and 79 were
unpatentable as anticipated by Brown.92 In discussing the Whereby Clause, the PTAB
agreed with SunPower that “the claims require resistance to wind uplift forces as a

88

D.I. 70 at 8.
See ‘988 patent, claims 1, 36, 56, 58.
90
D.I. 70 at 12.
91
Id.
92
D.I. 71, Ex. G at 2.
89

17

result of the claimed structural limitations,” but disagreed with SunPower that the clause
“sets forth an additional limitation, separate from the recited structure.”93 PanelClaw
notes the PTAB could not consider indefiniteness, enablement, or written description
under 35 U.S.C. § 112.94 Therefore, turning to the prior art, the PTAB found Brown
anticipated the claims because “the recited feature of resistance to wind uplift forces
constitutes a description of the result of photovoltaic assemblies having the recited
structural limitations” and “Brown discloses the claimed structures. Therefore, the
Brown structure resists wind uplift forces.”95
In the IPR, Stathopoulos testified that the claimed uplift resistance must be
achieved by the assembly’s “aerodynamic characteristics.”96 PanelClaw states he
explained that the size, shape, and thickness of the PV panels would affect wind uplift
resistance, and that whether an assembly would infringe would depend upon the size of
the access openings.97 PanelClaw also points to Stathopoulos’s testimony that certain
photovoltaic assemblies having spacers with access openings will not resist wind uplift,
and that, under certain circumstances, having an open region beneath a solar panel
would not create resistance to wind uplift.98 Lastly, PanelClaw states he testified that

93

Id., Ex. G at 7-8. In rejecting SunPower’s assertion that the Whereby Clause
“sets forth an additional limitation, separate from the recited structure,” the PTAB stated
that assertion was “not supported by the specification, which does not explain
adequately how to determine whether structure recited by the claims falls within the
scope of the claims . . . .” Id., Ex. G at 9.
94
D.I. 70 at 13; see 35 U.S.C. § 311(b) (limiting IPRs to anticipation and
obviousness).
95
D.I. 71, Ex. G at 12.
96
Id., Ex. H at 76.
97
D.I. 70 at 14 (citing D.I. 71, Ex. H at 42-47).
98
Id. (citing D.I. 71, Ex. H at 76, 113-14).
18

“interconnecting multiple photovoltaic assemblies does not necessarily resist wind uplift
forces,” and that “if the gaps between adjacent photovoltaic assemblies are too small,
interconnected photovoltaic assemblies can generate, rather than resist, wind uplift.”99
PanelClaw concludes the PTAB’s determination that the claims “require
resistance to wind uplift forces as a result of the claimed structural limitations” means
the clams are indefinite, because the structural characteristics that would achieve the
“whereby” language, e.g., aerodynamics, size, shape, weight, etc., are not claimed, and
Stathopoulos’s testimony that the claimed structure does not necessarily result in
resistance to wind uplift, demonstrates the asserted claims are indefinite.
The court agrees with SunPower that PanelClaw has not met its burden of
demonstrating by clear and convincing evidence that the asserted claims are indefinite
based on the current record.
First, the court is not bound by the PTAB’s decision.100 Therefore, the PTAB’s
discussion of the Whereby Clause is not determinative. Next, the testimony of
Stathopoulos’s during the IPR also fails to meet PanelClaw’s burden to show
indefiniteness. That PanelClaw cites his testimony that the claimed structure may or
may not resist wind uplift forces, depending on their particular characteristics, does not
convince the court its motion must be granted. As SunPower points out, the ‘988 patent
acknowledges that not all configurations of access openings are effective at resisting
99

Id. (quoting D.I. 71. Ex. H at 111).
St. Clair Intellectual Prop. Consultants, Inc. v. Matsushita Elec. Indus. Co.,
LTD., C.A. No. 04-1436–JJF-LPS, 2009 WL 3834541, at *9 (D. Del. Nov. 13, 2009)
(“Although the PTO appears to have found such a limitation in construing the disputed
claims under the ‘broadest reasonable construction’ standard, I accord the PTO’s views
on claim construction no deference.”).
100

19

wind uplift.101 Stathopoulos also submitted a declaration in this matter stating that by
reading the claims and the specification, one of ordinary skill in the art would readily
understand the Whereby Clause to refer to aerodynamic features of the claimed
assemblies.102
Finally, SunPower also asserted the ‘988 patent in the Sunlink case. Like
PanelClaw, the defendant in that case also argued the Whereby Clause was not
capable of construction, thus rendering the claims invalid under 35 U.S.C. § 112.103 The
Sunlink court, however, was able to construe that clause, determining that “whereby
wind uplift forces are resisted” meant “upward force of the wind on the assembly is
resisted.”104 That another district court construed the Whereby Clause while facing the
same type of invalidity argument indicates this court should proceed through the
Markman process with respect to that clause. Consequently, PanelClaw’s motion for
invalidity based on indefiniteness is denied.
In addition to its indefiniteness argument, PanelClaw maintains the asserted
claims of the ‘988 patent are invalid as not enabled, lacking adequate written
description, and/or as inoperative, because the patent purportedly does not teach any
assembly that is able resist wind uplift force using only an individual photovoltaic panel

101

D.I. 73 at 12; ‘988 patent, 6:66-7:6 ([W]ind tunnel investigations determined
that the preferred mode of operation is where spacers are normal to the direction of the
wind and following close to the perimeter of the module. Poor performance is
experienced where there is continuous blocking of the interior cavity around the
perimeter of the module.”) (emphasis added).
102
D.I. 73 at ¶¶ 20-23.
103
D.I. 78, Ex. A at 16-17.
104
SunPower Corp. v. Sunlink Corp., No. CV 08-2807 SBA, 2009 WL 2996724,
at *1 (N.D. Cal. Mar. 16, 2009).
20

and a spacer.105 PanelClaw argues the claims are directed to individual “assemblies”
made of a single panel and a single spacer with no mention of the perimeter
securement that PanelClaw states is required in all described embodiments to allow the
assembly to resist wind uplift force when installed on a roof.106 PanelClaw contends the
first embodiment is described as requiring “perimeter securement” to function.
According to the present invention, a lightweight, self-ballasting solar cell
roofing assembly is preferably formed with two portions. One portion
consists of a plurality of photovoltaic modules, together with
spacers which rest on a conventional building rooftop. The spacers
are preferably pre-formed and are sized and configured to provide
passageways beneath the photovoltaic module extending from at least
two sides of the modules to reduce lift forces on the modules. The
photovoltaic modules with spacers preferably have interlocking edges or
corners. The second portion is a means of perimeter securement
which avoid roof membrane penetrations, such as the use of roofing
pavers.
The photovoltaic module portion is situated over the building rooftop in a
manner to be exposed to solar radiation and electrically connected for
transport of electricity. The paver portion is situated over the same
building and interlocks with the photovoltaic modules with spacers. Other
means of perimeter securement are possible, including placing metal
flashing along the edge of the perimeter modules and connecting to the
flashing end-to-end around the array perimeter, or adhering said flashing
to the roofing membrane. The photovoltaic module performs the multiple
function normally provided by a roofing paver, including ballast, UV
protection, and weather protection for the membrane and insulation layers
below. Together the two portions serve the dual function of a selfballasted protective roof covering and an assembly for the collection
of radiant energy.107
PanelClaw notes the second “alternate” embodiment is formed with three
portions, but the assembly still includes the “perimeter securement” as the third portion.

105

D.I. 70 at 3, 15.
Id.
107
‘988 patent, 2:43-3:3 (emphasis added).
106

21

The first portion consists of a plurality of insulation blocks which are
situated on photovoltaic modules, together with spacers which rests
on the plurality of insulation blocks. The insulation blocks with
photovoltaic modules and spacers have interlocking edges. The
photovoltaic module performs multiple functions including ballast, UV
protection, and weather protection for the membrane and insulation layers
below. A third portion is a means of perimeter securement such as
metal flashing or conventional roofing pavers, located at the
perimeter of arrays of photovoltaic modules and tying the entire
array together as an integral assembly. Other means of perimeter
securement are also possible. Together the three portions serve the dual
function of a protected membrane roofing system and an assembly for the
collection of radiant energy.108
PanelClaw also argues the descriptions of the patent’s illustrations support its
position. Figures 1A-D illustrate a system in which the spacers rest directly on the
roofing membrane. The specification explains “[t]he modules and spacers placed in
arrays on top of the roofing membrane,” and “[r]oofing pavers are situated around the
perimeter of photovoltaic modules and interlock at the perimeter of the modules,” where
“[s]uch construction results in a simple, readily assembled roofing assembly which can
be lightweight while resisting the forces of wind uplift.”109 Figures 2A-2D illustrate an
embodiment in which the photovoltaic modules may instead be mounted on panels,
while Figures 3A-3D show a variation in which the spacers are installed over insulation
blocks. PanelClaw states the descriptions of Figures 2 and 3 do not recite any
mechanism for securing the different types of panel assemblies on a roof without using
the perimeter securement described in connection with Figure 1.110 Figures 4A and 4B
show “sectional views of alternate means of perimeter securement for the roof tile

108

‘988 patent, 3:5-21 (emphasis added).
‘988 patent, 5:29-33.
110
D.I. 70 at 10.
109

22

system,” while Figure 5 “shows a perspective view of the photovoltaic roofing assembly
where solar roofing tiles 504 form an array 502 which is situated on a building rooftop,”
and “[p]erimeter securement 510 runs the perimeter of array 502 and ties the roofing
tiles 504 into an integral assembly.”111 The specification explains that “[t]he advantages
of the foregoing assembly,” include that “the assembly is lightweight (9.76-19.53 kg/sq.
m or 2-4 pounds/sq. ft.) relative to conventional roofing ballast (48.8-73.2 kg/sq. m or
10-15 pounds/sq. ft.), relying on a combination of weight, edge to edge connection, and
spacer geometry to resist the forces of uplift.”112 According to PanelClaw, “the foregoing
assembly” is the entire rooftop system, including the perimeter securement, and it is
able to fall within those weight ranges only because the assembly includes the
perimeter securement.113
PanelClaw concludes that the patent does not provide any description of, or
enable one of skill in the art to make, a single panel/spacer combination that resists
wind uplift force.114 PanelClaw maintains that using the teaching of the ‘988 patent, it is
impossible to achieve resistance to “wind uplift forces when said photovoltaic assembly
is mounted to a support surface” with only a photovoltaic panel and a spacer, and it
would also be impossible to achieve with a photovoltaic panel and a spacer that are 2-4
psf.115 It concludes that because the claims are not commensurate with the disclosure,

111

‘988 patent, 7:50-67.
‘988 patent, 5:34-40.
113
D.I. 70 at 10.
114
Id. at 3, 15.
115
Id. at 15. Dependant claims 18, 63, 65, and 66 each require that “the
photovoltaic module and spacer have a combined weight of about two to four pounds
per square foot.”
112

23

they are invalid under 35 U.S.C. § 112, as not enabled and lacking written description,
and/or under 35 U.S.C. § 101 as inoperative and lacking utility.116
SunPower insists PanelClaw has not met its burden to show the ‘988 patent
claims are invalid for lack of enablement, written description, or operability as
PanelClaw presents no evidence in support of its motion and instead relies only on
attorney argument.117 First, SunPower argues PanelClaw’s enablement and written
description arguments are fatally flawed for failure to provide any evidence or argument
about a person of ordinary skill in the art.118 Moreover, it maintains PanelClaw’s motion
should be denied because enablement and written description are inherently factual
analyses and PanelClaw has purportedly presented no facts–only attorney argument.119
The court agrees with SunPower that PanelClaw’s attorney argument in support
of its contention that the claims do not meet the enablement and written description
requirements and/or the claimed invention is inoperative is insufficient to support its

116

Id. at 3, 15.
D.I. 73 at 13.
118
Id. (citing AAT Bioquest, Inc. v Texas Fluorescence Labs., Inc., No. 14-CV3909-DMR, 2015 WL 1738402, at *5 (N.D. Cal. Apr. 13, 2015) (“TEFLabs’s failure to
provide any evidence or argument regarding what constitutes ‘persons or ordinary skill
in the art’ dooms its motion for summary judgment on the written description
requirement.”)).
119
Id. (citing Cephalon, Inc. v. Watson Pharm, Inc. 707 F.3d 1330, 1336 (Fed.
Cir. 2005) (“Whether undue experimentation is required in the enablement analysis is
not a single, simple factual determination, but rather is a conclusion reached by
weighing many factual considerations.”) (internal quotation marks omitted); Masimo
Corp. v. Philips Elec. N. Am. Corp., 62 F. Supp. 3d 368, 381 (D. Del. 2014) (denying
summary judgment for inadequate written description because of the “longstanding
principle that the written description inquiry is quintessentially a question of fact.”)
(internal quotation marks omitted)).
117

24

motion for summary judgment.120 PanelClaw’s assertion that “[b]ecause the claims lack
the perimeter, their subject matter is neither enabled nor adequately described”121 is a
conclusory attorney argument, not evidence. PanelClaw’s reliance on the preferred
embodiments having perimeter securement is also unpersuasive. PanelClaw insists it
not attempting to read perimeter securement into the claims, but is merely observing
that the perimeter securement is not recited in the asserted claims, and the patent
describes no assembly that is able to function without it.122 The Federal Circuit has
forcefully stated that specific aspects of a preferred embodiment are not required to be
incorporated into claims that do not recite such aspects.
[A]lthough the specification often describes very specific embodiments of
the invention, we have repeatedly warned against confining the claims to
those embodiments. In particular, we have expressly rejected the
contention that if a patent describes only a single embodiment, the claims
of the patent must be construed as being limited to that embodiment.123
Also, the patent expressly provides that:
“[w]hile the invention has been described in its preferred embodiments, it
is to be understood that the words which have been used are words of
description rather than limitations and that changes may be made within
the purview of the appended claims without departing from the true scope
120

Celotex Corp. v. Catrett, 477 U.S. 317, 323 (1986) (The party moving for
summary judgment bears the initial burden of showing the absence of genuine issues of
material fact.); see Invitrogen Crop. v. Clontech Labs., Inc., 429 F.3d 1052, 1068 (Fed.
Cir. 2005) (“Unsubstantiated attorney argument regarding the meaning of technical
evidence is no substitute for competent expert testimony. It does not, and cannot,
support [defendant’s] burden on summary judgment.”); cf. Ferring B.V. v. Barr Labs.,
Inc., 437 F.3d 1181, 1193 (Fed. Cir. 2006) (“Conclusory allegations and attorney
arguments are insufficient to overcome a motion for summary judgment.”) (citations
omitted).
121
D.I. 70 at 15.
122
D.I. 77 at 8.
123
Phillips v. AWH Corp., 415 F.3d 1303, 1323 (Fed. Cir. 2005) (en banc)
(citations omitted).
25

and spirit of the invention in its broader aspects.124
Moreover, where the applicants intended perimeter securement to be a limitation, that
limitation was included.125
Finally, SunPower submits the declaration of its expert, Stathopoulos, in which he
opines that one of ordinary skill in the art would read the ‘988 patent specification and
claims and readily understand the invention resists wind uplift not by weight alone but
because of the aerodynamic features of its photovoltaic assemblies; would readily
understand the particular structural elements of the claims are described in detail
throughout the specification; could readily understand how to build the claimed
assemblies without undue experimentation; and could design, model, and test suitably
in an appropriate wind tunnel the claimed invention which would work in actual
deployment–even with a single panel/spacer.126
Consequently, the court determines PanelClaw has failed to demonstrate by
clear and convincing evidence that the asserted claims are invalid for failure to meet the
enablement and written description requirements and/or the invention’s inoperability and
its motion is denied.
V.

CONCLUSION
For the aforementioned reasons, PanelClaw’s motion for summary judgment (D.I.
124

‘988 patent, 8:1-6.
See, e.g., ‘988 patent, claim 22 (“assembly . . . further comprising perimeter
ties situated around the photovoltaic array and joined with said photovoltaic array to
make an integral array assembly”); claim 23 (“assembly . . . wherein said perimeter ties
are joined with one another whereby the integral array assembly is tied together and
strengthened”); claim 24 (“assembly wherein said perimeter ties comprise a chosen one
of concrete pavers and hollow metal flashing units”).
126
D.I. 75 at ¶¶ 20-25.
125

26

69) is GRANTED in part and DENIED in part. An appropriate order shall issue.

Dated: April 1, 2016

/s/ Mary Pat Thynge
UNITED STATES MAGISTRATE JUDGE

27