This case was previously before us in AquaTex Industries, Inc. v. Techniche Solutions, 419 F.3d 1374 (Fеd.Cir.2005). We held that claims 1 and 9 of U.S. Patent No. 6,371,977 (“the '977 patent”) were not literally infringed, but we did not foreclose a finding of infringement under the doctrine of equivalents. We remanded for “the trial court [to] consider whether or not each limitation of the claims in dispute, or its equivalent, is present in the accused Tech-niche products.” Id. at 1383. On remand the district court granted summary judgment of non-infringement, and the plaintiff patent holder AquaTex Industries, Inc. (“AquaTex”) now appeals. We hold that the district court erred in finding the doctrine of equivalents barred by prosecution history estoppel and in relying on unclaimed features to find a lack of equivalents. However, we affirm the grant of summary judgment because AquaTex did not satisfy its burden to present particularized evidence of equivalents in opposition to the motion for summary judgment.
BACKGROUND
Having already described the background of this case in
AquaTex,
AquaTex is the assignee of the '977 patent. The '977 patent claims a method for cooling a person through evaporation by use of a multi-layered, liquid-retaining composite material in evaporative cooling garments. Defendant Techniche Solutions (“Techniche”) also manufactures multi-lay-ered, liquid-retaining composite materials for use in evaporative cooling garments.
AquaTex sued Techniche alleging that its product infringed claims 1 and 9 of the '977 patent. These claims claim a method оf cooling a person using a certain device (i.e., “a multi-layered, liquid-retaining composite material”). Claim 1 claims a method performed using a device “comprising a fiberfill batting material, and hydrophilic polymeric fibers that absorb at least about 2.5 times the fiber’s weight in water.” 1 '977 patent col. 13 1. 67 to col. 14 1. 2. Claim 9 similarly claims a method performed using a device with “a filler layer comprising: a fiberfill batting material and hydrophilic polymeriс particles.” 2 '977 patent col. 14 11. 39-41. The differences between claims 1 and 9 are of no relevance to this appeal. AquaTex did not assert that Techniche performed the actual method but instead asserted that Techniche made a product its consumers used to perform the method. Therefore the suit was for contributory infringement.
In 2004, Techniche moved for summary judgment of non-infringement. It conceded that most of the claim limitations were *1324 satisfied. But Techniche asserted that it uses a commercially available product called Vizorb® as its filler layer and that Vizorb® is an airlaid non-woven fabric predominately made of cellulose fluffed pulp, incorporating both natural and synthetic fibers. The question was whether Vizorb® satisfied the “fiberfill batting material” limitation. Techniche claimed that it did not because only a batting material containing exclusively synthetic fibers constituted “fiberfill.”
The district court construed the claim language to require only synthetic batting material and found no literal infringement because Vizorb® includes natural fibers. The district court also found that the claim of infringement under the doctrine of equivalents was barred by prosecution history estoppel. During prosecution, Aqua-Tex amended its claims to distinguish the Zafiroglu prior art patent, U.S. Patent No. 4,897,297, by claiming that its method cooled by evaporаtion whereas Zafiroglu cooled through use of a compress and involved only slight evaporation over time. Specifically, AquaTex amended the limitation in claims 1 and 9 from “[a] method of cooling a person” to “[a] method of cooling a person by evaporation”', it also added the phrase “and evaporatively cooling said person” at the end of the limitation requiring “employing said multi-layered, liquid-retaining composite as a garmеt or a flat sheet.” Before the examiner, AquaTex also argued that Zafiroglu was distinguishable on various grounds. As a result of these arguments, the district court held that estoppel barred a claim that Tech-niche’s accused product was equivalent.
On appeal we affirmed the district court’s finding of no literal infringement. We concluded that, though the prosecution history was ambiguous, the examples of fiberfill in the specifications, the three patents incorporated by reference, and the extrinsic evidence (dictionaries and other industry sources) all suggested that fiberfill was synthetic material.
AquaTex,
On remand the district court considered the issue on the existing record but requested supplemental briefing from the parties on the doctrine of equivalents. In its supplemental brief Techniche argued that: (1) AquaTex was barred by amendment estoppel from asserting the doctrine of equivalents; (2) its product did not include the equivalent of fiberfill batting; and (3) AquaTex provided “only conclusory statements regarding equivalence, without any particularized testimony and linking argument as to the ‘insubstantiality of the differences’ between the claimed invention and the accused device, or with respect to the ‘function, way, result test’ ” as required by
Texas Instruments, Inc. v. Cypress Semiconductor Corp.,
AquaTex timely appealed. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1) (2000).
DISCUSSION
I
Techniche has admitted that most of the limitations of claims 1 and 9 of the '977 patent are satisfied by use of the Vizorb® filler layer. Thus, Techniche admitted that use of its product involved: (1) “a method for cooling a person by evaporation,”
see
Appellee’s Br. 7 n. 2,
AquaTex,
A
Reliance on the doctrine of equivalents may be foreclosed by prosecution history estoppel.
Warner-Jenkinson Co. v. Hilton Davis Chem. Co.,
However, the district court’s approach is foreclosed by our prior opinion, which held that “[t]he subject matter surrendered by the narrowing amendment bears no relation to the composition of the fiberfill batting material.”
AquaTex,
B
A finding of infringement under the doctrine of equivalents requires a showing that the difference between the claimed invention and the accused product or method was insubstantial or that the accused product or method performs the substantially same function in substantially the same way with substantially the same result as each claim limitation of the patented product or method.
AquaTex,
In addition to finding the doctrine of equivalents barred by prosecution history estoppel, the district court concluded that Vizorb® was not equivalent to the “fiberfill batting material” limitation because AquaTex failed to show that “Defendant’s filler layer includes a
hydrophobic
material, like the fiberfill used in Plaintiffs product, to
create air pockets
to
promote evaporation.” AquaTex,
There is nothing in the “fiberfill batting limitation” of claims 1 and 9 of the '977 patent, nor in the specification, that indicates that its function is to promote evaporation. The “fiberfill batting material” claim itself does not indicate any specific function beyond general service as part of the filler layer. The only function given to the fiberfill in the specification is a negative function; “any commercial fiberfill may be used as long as it does not adversely affect the performance of the end composite.” '977 patent col. 3 11. 48-50 (emphasis added). Thus, promotion of evaporation is not a function of the fiberfill identified in the claims or the specification of the '977 patent; instead the specification only says that the fiberfill cannot retard evaporation (i.e., the performance of the end composite). While the specification does suggest that “[t]he blend [of hydrophilic polymers and the fiberfill material] both promotes evaporation qualities and provides a means to hold cool or hold hot,” '977 patent col. 6 11. 34-36 (emphasis added), this statement merely describes a function of the filler layer as a whole, not the “fiberfill batting material” in particular.
Even if the function of the fiberfill were to promote evaporation, the district court erred in concluding that hydrophobic material and air pockеts were the way in which fiberfill promoted evaporation. Neither the use of hydrophobic material nor the creation of air pockets in the filler layer for evaporation is identified in the claims or specification of the '977 patent as a way in which the “fiberfill batting material” limitation functions. The district court asserted that “there is little question upon reading the specification” as a whole that the fiberfill is water-resistant and creates air pockets for evaporation.
AquaTex,
The district court appears to have found these distinguishing features in “[ijnformation taken from Plaintiffs website” that it believed “confirm[ed]” its reading of the specifications.
Id.
at *6.
6
Specifically, the district court quoted the following description of AquaTex’s product from its website: “The
hydrophobic
fill evenly distributes and
surrounds the charged fibers with air,
creating an ideal environment for evaporation.”
Id.
at *6 (emphasis added). This reliance on the characteristics of the patentee’s product was erroneous. “Infringement, either literally or under the doctrine of equivalents, does not arise by comparing the accused product ... with a commercialized embodiment of the patentee.”
Johnson & Johnston
Assocs.
Inc. v. R.E. Serv. Co.,
Thus, the district court erroneously relied on feаtures not disclosed in the patent in concluding that Techniche’s Vizorb® layer was not equivalent to the “fiberfill batting material” limitation.
II
Although both grounds for the district court’s summary judgment ruling were erroneous, “[w]e review [the] district court’s grant of summary judgment de novo.”
AquaTex,
AquaTex has suggested that the function of the filler layer in the patent was retaining and distributing absorbent materials throughout the filler layer and that Techniche’s filler layer performs this function in thе same way. This alleged function more nearly corresponds to the claims and specification of the patent than the function identified by the district court.
See
'977 patent col. 8 11. 57-59 (noting that the “fiberfill-type batting ... retains tiny absorbent particles [that] are distributed throughout the batting.”). However, AquaTex, as the plaintiff, was required to prove (by a preponderance of the evidence) infringement under the doctrine of equivalents.
PSC Computer Prods., Inc. v. Foxconn Int'l, Inc.,
Pursuant to our precedent, a patentee must ... provide particularized testimony and linking argument as to the ‘insubstantiality of the differences’ between the claimed invention and the accused device or process, or with respect to the function, way, result test when such evidence is presented to support a finding of infringement under the doctrine of equivalents. Such evidence must be presеnted on a limitation-by-limitation basis. Generalized testimony as to the overall similarity between the claims and the accused infringer’s product or process will not suffice.
Id.
at 1567 (emphasis added). “The same rule applies in the summary judgment context.”
Network Commerce, Inc. v. Microsoft Corp.,
Both the Supreme Court and this court have made clear that the evidence of equivalents must be from the perspective of someone skilled in the art, for example “through testimony of experts or others versed in the technology; by documents, including texts and treatises; and, of course, by the disclosures of the prior art.”
See Graver Tank & Mfg. Co.,
In this case AquaTex, in response to the motion for summary judgment of non-infringement, provided no particularized testimony from an expert or person skilled in the art that specifically addressed equivalents “on a limitation-by-limitation basis;” explained the insubstantiality of the differences between the patented method and the accused product; or discussed the function, way, result test.
Texas Instruments,
In short, in opposing summary judgment, AquaTex only provided lawyer argument and generalized testimony about the accused product. It has failed to demonstrate a genuine issue of mаterial fact that would prevent the grant of summary judgment.
CONCLUSION
The district court erred in finding the doctrine of equivalents barred by prosecution history estoppel and in comparing the accused product to the patentee’s commer *1330 cial embodiment. However, AquaTex failed to show the existence of a genuine issue of material fact or provide any particularized testimony on equivalents. Summary judgment was therefore aрpropriate.
AFFIRMED
COSTS
No costs.
Notes
. Claim 1 states in full:
A method of cooling a person by evaporation, comprising:
providing a multi-layered, liquid-retaining composite material comprising a fiberfill batting material,
and hydrophilic polymeric fibers that absorb at least about 2.5 times the fiber's weight in water;
soaking said multi-layered composite in a liquid;
employing said multi-layered, liquid-retaining composite material as a garment or a flat sheet and evaporatively cooling said person.
. Claim 9 states in full:
A method of cooling a person by evaporation, comprising:
providing a multi-layered, liquid-retaining composite material comprising:
a filler layer comprising:
a fiberfill batting material and
hydrophilic polymeric particles;
soaking said multi-layered, liquid-rеtaining composite in a liquid; and
employing said multi-layered, liquid-retaining composite as a garment or a flat sheet and evaporatively cooling said person.
. In its remand brief Techniche asserted that its products did not satisfy the "method of cooling by evaporation" or "hydrophilic polymeric particles" limitations.
However, in its brief in the initial appeal to this court, Techniche conceded that "[fjor purposes of the motion for summary judgment, it is undisputed that the Defendant manufactures and markets
evaporative cooling
garments ... [and][t]here is also no dispute that Defendant's product contains hydrophilic polymeric particles or fibers." Appellee’s Br. 7 n. 2,
AquaTex,
. Although the district court’s holding on prosecution history estoppel ultimately rests on estoppel by amendment,
AquaTex,
. "In some cases, the patent's prosecution history also may reveal the identification of a specific function relating to claimed structure.”
Vehicular Techs.,
. Somewhat inconsistently, the district court at the same time disclaimed any reliance on the patentee’s website.
AquaTex,
. Even where literal infringement is involved, expert infringement testimony is generally required in cases involving complex technology.
See Centricut, LLC v. Esab Group, Inc.,
