United States Court of Appeals 

for the Federal Circuit 

__________________________ 

SIEMENS MEDICAL SOLUTIONS USA, INC., 

Plaintiff-Cross Appellant, 

v. 

SAINT-GOBAIN CERAMICS & PLASTICS, INC., 

Defendant-Appellant. 

__________________________ 

2010-1145, -1177 

__________________________ 

Appeals from the United States District Court for the 

District of Delaware in Case No. 07-CV-0190, Judge Sue 

L. Robinson. 

__________________________ 

Decided: February 24, 2011 

__________________________ 

CARTER G. PHILLIPS, Sidley Austin LLP, of Washington, DC, argued for plaintiff-cross appellant. With him 

on the brief were VIRGINIA A. SEITZ and JAMES C. OWENS. 

Of counsel on the brief was ARTHUR I. NEUSTADT, Oblon 

Spivak McClelland Maier & Neustadt, L.L.P., of Alexandria, Virginia. 

GREGG F. LOCASCIO, Kirkland & Ellis, LLP, of Washington, DC, argued for defendant-appellant. With him on 

the brief were JOHN C. O’QUINN, WILLIAM H. BURGESS, 
SIEMENS MEDICAL v. SAINT GOBAIN 2

MICHAEL A. PEARSON, JR.; and ROBERT G. KRUPKA, of Los 

Angeles, California. 

__________________________ 

Before LOURIE, LINN, and PROST, Circuit Judges. 

Opinion for the court filed by Circuit Judge LOURIE. 

Dissenting opinion filed by Circuit Judge PROST. 

LOURIE, Circuit Judge. 

Saint-Gobain Ceramics & Plastics, Inc. (“SaintGobain”) appeals from the decision of the United States 

District Court for the District of Delaware denying SaintGobain’s motion for judgment as a matter of law (“JMOL”) 

or for a new trial following the jury’s finding that SaintGobain infringed U.S. Patent 4,958,080 (the “’080 patent”) 

under the doctrine of equivalents. Siemens Med. Solutions USA, Inc. v. Saint-Gobain Ceramics & Plastics, Inc., 

615 F. Supp. 2d 304 (D. Del. 2009) (“JMOL Opinion”). 

Siemens Medical Solutions USA, Inc. (“Siemens”) crossappeals from the district court’s grant of Saint-Gobain’s 

motion for JMOL reducing the jury’s award of damages. 

Id. 

Because we discern no legal error in the court’s jury 

instructions and no abuse of discretion in the court’s 

evidentiary rulings, we affirm the decision of the district 

court denying Saint-Gobain’s motion for JMOL or a new 

trial. However, for the reasons stated below, we vacate 

the district court’s damages award and remand for a 

determination of additional damages. 

BACKGROUND

Positron emission tomography (“PET”) is a nuclear 

medical imaging technique that provides images and 

information about the chemical structure and function of 

a patient’s organ systems. JMOL Opinion at 307. To 
3 SIEMENS MEDICAL v. SAINT GOBAIN

obtain a PET scan, a patient is administered a radioactive 

isotope and enters the PET scanner. As the isotope 

decays in the patient’s body, it emits positrons. When a 

positron collides with an electron in the patient’s body, 

two gamma-ray photons are produced, which exit the 

patient’s body. The photons are detected by the PET 

scanner’s radiation detector, which contains thousands of 

scintillator crystals arranged in a ring around the patient’s body. As the district court found, “[a] scintillator, 

generally, is a substance that absorbs high energy radiation and, in response, fluoresces photons at a specific, 

longer wavelength, releasing the previously absorbed 

energy.” Id. at 307 n.1. The scintillator crystals convert 

the emitted gamma rays into visible light, which is then 

detected to produce a three-dimensional image of the 

radioactivity in the patient. This image provides useful 

diagnostic information about the patient’s organ systems. 

Id. at 307. 

Siemens develops, manufactures, and sells PET scanners. The scintillator crystals in Siemens’ PET scanners 

consist of cerium-doped lutetium oxyorthosilicate (“LSO”). 

JMOL Opinion at 307. Saint-Gobain manufactures and 

sells scintillator crystals for use in PET scanners. SaintGobain’s crystals consist of cerium-doped lutetiumyttrium orthosilicate (“LYSO”), which differs chemically 

from LSO in that some of the lutetium is substituted for 

by yttrium. Id. Specifically, Saint-Gobain’s crystals are 

10% Y LYSO, meaning that 10% of the lutetium atoms 

are substituted for by yttrium atoms. Saint-Gobain sells 

its scintillator crystals to Philips Medical Systems (“Philips”), which manufactures and sells PET scanners that 

compete with those sold by Siemens. Id. at 308. 

Siemens owns the ’080 patent, which relates to radiation detectors comprising an LSO scintillator crystal and 

a photodetector. JMOL Opinion at 307; J.A. 1210-11. 
SIEMENS MEDICAL v. SAINT GOBAIN 4

The ’080 patent was filed on August 4, 1989 and expired 

on October 6, 2008. JMOL Opinion at 307. Claim 1 of the 

’080 patent reads as follows: 

1. A gamma ray or x-ray detector, comprising: 

a scintillator composed of a transparent single 

crystal of cerium-activated lutetium oxyorthosilicate having the general formulation 

Ce2xLu2(1-x)SiO5, where x is within the range of 

from approximately 2×10–4 to approximately 

3×10–2, and 

a photodetector optically coupled to the scintillator for producing an electrical signal in response 

to the emission of a light pulse by the scintillator. 

’080 patent col.12 ll.7-15. 

Although the ’080 patent is the only asserted patent 

in this case, the parties’ arguments on appeal involve two 

additional patents. U.S. Patent 6,624,420 (the “’420 

patent”), which is licensed to Saint-Gobain, discloses 

radiation detectors comprising LYSO scintillator crystals. 

JMOL Opinion at 307-08. Claim 1 of the ’420 patent 

recites: 

1. A scintillator detector for high energy radiation comprising: a monocrystalline structure of 

cerium doped lutetium yttrium orthosilicate, 

Ce2x,(Lu1-yYy)2(1-x)SiO5 where x=approximately 

0.0001 to approximately 0.05 and 

y=approximately 0.0001 to approximately 0.9999. 

’420 patent col.7 ll.39-43. As the formula in claim 1 

indicates, the LYSO crystals disclosed in the ’420 patent 

range from 0.01% Y to 99.99% Y. The specification of the 

’420 patent states that LYSO crystals comprising 30% Y, 

50% Y, 70% Y, and 85% Y were prepared. Id. col.4 ll.51-

58. The ’420 patent was filed on February 17, 2000, and 
5 SIEMENS MEDICAL v. SAINT GOBAIN

its front page lists the ’080 patent among the “References 

Cited.” 

The parties also reference U.S. Patent 6,323,489 (the 

“’489 patent”), another patent disclosing LYSO scintillator 

crystals. The ’489 patent was the subject of an interference action with the patent application that issued as the 

’420 patent. Claim 1 of the ’489 patent recites: 

1. A crystal scintillator comprising a transparent single crystal of cerium-activated lutetium 

yttrium oxyorthosilicate having the general formula Lu(2-x-z)YxCezSiO5, wherein 0.05≤x≤1.95 and 

0.001≤z≤0.02. 

’489 patent col.5 ll.2-5. Unlike the ’420 patent, the specification of the ’489 patent discloses the preparation of a 

crystal consisting of 10% Y LYSO. Id. col.3 l.64–col.4 l.1. 

The ’489 patent was surrendered following an adverse 

decision in the interference proceeding. JMOL Opinion at 

307 n.3. 

In April 2007, Siemens sued Saint-Gobain for infringement, including willful infringement, of claims 1 

and 2 of the ’080 patent. JMOL Opinion at 307. Siemens’ 

infringement theory relied on the doctrine of equivalents. 

Siemens alleged that Saint-Gobain was liable for contributory and induced infringement under 35 U.S.C. 

§§ 271(b) and (c) by selling 10% Y LYSO crystals to Philips for use in its PET scanners. Id. at 308-09. SaintGobain argued in response that PET scanners comprising 

its 10% Y LYSO crystals did not infringe the ’080 patent 

under the doctrine of equivalents.1 Saint-Gobain argued, 

in particular, that its LYSO crystals are not equivalent to 

 1 The parties did not dispute that, aside from the 

scintillator crystals, the PET scanners at issue literally 

satisfied all other limitations of claims 1 and 2 of the ’080 

patent. JMOL Opinion at 308. 
SIEMENS MEDICAL v. SAINT GOBAIN 6

those claimed in the ’080 patent, because its crystals are 

separately claimed in the ’420 patent. Id. at 308. In 

defense to Siemens’ allegation of willfulness, SaintGobain pointed out that it obtained a license to the ’489 

patent and then, after the interference, to the ’420 patent. 

Id. at 311-12. 

A jury trial was held from September 17 to 25, 2008. 

Id. Despite Saint-Gobain’s request for a higher evidentiary standard to prove equivalence (an issue we discuss 

further below), the court instructed the jury that Siemens 

must prove contributory and induced infringement under 

the doctrine of equivalents by a preponderance of the 

evidence. Id. at 309. Regarding the ’420 patent, the court 

instructed the jury as follows: 

[Y]ou have heard evidence that Saint-Gobain 

has a license under the [’420] patent to produce its 

10% Y LYSO crystal. In connection with this evidence, I instruct you that a product that is covered 

by a subsequent patent may still infringe an earlier patent. Nonetheless, in considering the issue 

of infringement under the doctrine of equivalents, 

you may consider that Saint-Gobain obtained the 

license under the [’420] patent, which may be 

some evidence that the differences between the 

10% Y LYSO crystal and the claimed LSO crystal 

are substantial. Such evidence may be considered 

along with other evidence of the similarities and 

differences between the claimed LSO crystal and 

Saint-Gobain’s 10% Y LYSO crystal. It is for you 

to decide the issue of whether Saint-Gobain’s 10% 

Y LYSO crystal constitutes an equivalent to the 

claimed LSO crystal of the ’080 patent. 

Id.; J.A. 451. The court also instructed the jury that, in 

the event it found infringement, it could consider a rea-
7 SIEMENS MEDICAL v. SAINT GOBAIN

sonable royalty and lost profits as damages. JMOL 

Opinion at 309; J.A. 467-70. 

The jury found in favor of Siemens on infringement 

and awarded total damages of $52.3 million.2 Id. The 

jury also found that Saint-Gobain’s infringement was not 

willful. Id. Saint-Gobain filed a post-trial motion for 

JMOL or a new trial, in which Saint-Gobain challenged 

the following decisions of the district court: (1) a decision 

not to instruct the jury that infringement by equivalence 

must be proved in this case by clear and convincing evidence; (2) a decision not to instruct the jury that the ’420 

patent is presumed valid; (3) a decision not to admit into 

evidence the ’489 patent and certain expert testimony; 

and (4) a decision to permit the jury to consider lost 

profits damages. Saint-Gobain further argued that the 

court should remit the jury’s damages award. 

In its opinion and order dated May 15, 2009, the district court denied Saint-Gobain’s post-trial motion for 

JMOL or for a new trial. JMOL Opinion at 320. However, the court granted Saint-Gobain’s request to reduce 

the jury’s damages award, finding that evidence supported the jury verdict only up to $44,937,545. Id. at 319. 

In particular, the court found substantial evidence that 

Saint-Gobain sold 79 PET scanners’ worth of crystals to 

Philips and that Philips sold 61 scanners prior to the 

expiration of the ’080 patent, but that Philips’ sale of the 

additional 18 scanners was “wholly speculative.” Id. at 

318-19. The court therefore awarded lost profits damages 

corresponding to 61 scanners based on the per scanner 

 2 The verdict form did not ask the jury to specify 

whether its award resulted from a calculation of reasonable royalty, lost profits, or a combination of the two. J.A. 

476-77.
SIEMENS MEDICAL v. SAINT GOBAIN 8

profit estimate of Siemens’ damages expert.3 Id. at 319. 

The court entered final judgment on December 16, 2009. 

The parties timely appealed and cross-appealed. We 

have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

DISCUSSION

Saint-Gobain appeals the district court’s denial of its 

motion for JMOL or for a new trial. In particular, SaintGobain challenges the district court’s jury instructions 

with regard to the doctrine of equivalents and the presumption of validity, the decision of the district court to 

exclude certain evidence, and the district court’s decision 

to permit the jury to consider lost profits damages. Siemens cross-appeals the district court’s reduction of the 

jury’s damages award. 

We review the denial of a motion for JMOL or for a 

new trial under the law of the pertinent regional circuit. 

Seachange Int’l, Inc. v. C-Cor Inc., 413 F.3d 1361, 1367-68 

(Fed. Cir. 2005). The Third Circuit exercises plenary 

review of a denial of JMOL, applying the same standard 

as the district court. Curley v. Klem, 499 F.3d 199, 205-06 

(3d Cir. 2007); Rinehimer v. Cemcolift, Inc., 292 F.3d 375, 

383 (3d Cir. 2002). In the Third Circuit, “[t]he standard of 

review on a motion for a new trial is abuse of discretion 

unless the court’s denial of the motion is based on application of a legal precept, in which case our review is plenary.” Curley, 499 F.3d at 206 (internal quotation marks 

omitted); Lightning Lube, Inc. v. Witco Corp., 4 F.3d 1153, 

1167 (3d Cir. 1993). 

 3 The court also awarded lost profits damages for 

service contracts on PET scanners sold in the United 

States; these damages are included in the total of 

$44,937,545. JMOL Opinion at 319. 
9 SIEMENS MEDICAL v. SAINT GOBAIN

A. Jury Instructions 

Whether a jury instruction is legally erroneous is a 

question of law. Advanced Display Sys., Inc. v. Kent State 

Univ., 212 F.3d 1272, 1282 (Fed. Cir. 2000). “This court 

reviews the legal sufficiency of jury instructions on an 

issue of patent law without deference to the district court. 

. . . and only orders a new trial when errors in the instructions as a whole clearly mislead the jury.” DSU Med. 

Corp. v. JMS Co., 471 F.3d 1293, 1304 (Fed. Cir. 2006) (en 

banc in relevant part) (internal quotation marks omitted). 

Moreover, a jury verdict will be set aside, based on erroneous jury instructions, if the movant can establish that 

“those instructions were legally erroneous” and that “the 

errors had prejudicial effect.” Advanced Display, 212 F.3d 

at 1281.

1. Burden of Proof for Infringement under the Doctrine of 

Equivalents 

Saint-Gobain argues that the district court legally 

erred in its jury instructions regarding proof of infringement under the doctrine of equivalents. Saint-Gobain 

asserts that, in cases where an alleged equivalent is 

separately patented, a heightened evidentiary burden is 

required. In particular, Saint-Gobain argues that, because its 10% Y LYSO crystals are covered by the ’420 

patent, the district court erred by not instructing the jury 

that a finding of equivalence between the 10% Y LYSO 

crystals and the LSO crystals of the ’080 patent necessitates proof beyond that of a preponderance of the evidence. 

Saint-Gobain’s rationale for this heightened burden is 

the following: The jury’s finding of equivalence “constructively invalidated” the ’420 patent, because “a legal conclusion of invalidity for obviousness was . . . the clearly 

implied result of the jury’s verdict.” Opening Br. of Def.-
SIEMENS MEDICAL v. SAINT GOBAIN 10

Appellant Saint-Gobain at 21. Thus, due to this implied 

result, the district court legally erred by failing to instruct 

the jury that equivalence must be found by clear and 

convincing evidence—i.e., the evidentiary burden required 

to overcome the statutory presumption of validity under 

35 U.S.C. § 282. In support of its argument, Saint-Gobain 

relies on Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., in which we stated, “when a device that incorporates the purported equivalent is in fact the subject of a 

separate patent, a finding of equivalency, while perhaps 

not necessarily legally foreclosed, is at least considerably 

more difficult to make out.” 493 F.3d 1368, 1379-80 (Fed. 

Cir. 2007) (internal footnote omitted). On account of the 

allegedly erroneous jury instruction, Saint-Gobain asks us 

to set aside the jury verdict of infringement and order a 

new trial. 

In response, Siemens argues that, even in cases of 

separate patentability, infringement by equivalence is 

proved by a preponderance of the evidence. According to 

Siemens, our cases consistently hold that although the 

fact of separate patentability may be considered by the 

jury along with other relevant evidence of noninfringement, this fact does not alter the required burden of proof. 

Siemens argues that the statement in Festo is dictum and 

points instead to cases including Hoechst Celanese Corp v. 

BP Chems. Ltd., 78 F.3d 1575, 1582 (Fed. Cir. 1996), in 

which we explained that “[t]he fact of separate patentability presents no legal or evidentiary presumption of noninfringement.” Because the jury was correctly instructed, 

Siemens argues, the verdict of infringement should be 

affirmed. 

The doctrine of equivalents prohibits one from avoiding infringement liability by making only “insubstantial 

changes and substitutions . . . which, though adding 

nothing, would be enough to take the copied matter 
11 SIEMENS MEDICAL v. SAINT GOBAIN

outside the claim, and hence outside the reach of law.” 

Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 

605, 607 (1950). The “essential inquiry” in any determination under the equivalents doctrine is whether “the 

accused product or process contain[s] elements identical 

or equivalent to each claimed element of the patented 

invention.” Warner-Jenkinson Co., Inc. v. Hilton Davis 

Chem. Co., 520 U.S. 17, 40 (1997). We have assessed the 

insubstantiality of an alleged equivalent by applying the 

function-way-result test as set forth in Union Paper-Bag 

Mach. Co. v. Murphy, 97 U.S. 120, 125 (1877), which asks 

whether an element of an accused product “performs 

substantially the same function in substantially the same 

way to obtain the same result” as an element of the patented invention. See, e.g., TIP Sys., LLC v. Phillips & 

Brooks/Gladwin, Inc., 529 F.3d 1364, 1376 (Fed. Cir. 

2008); Abraxis Biosci., Inc. v. Mayne Pharma (USA) Inc., 

467 F.3d 1370, 1379 (Fed. Cir. 2006); see also Graver 

Tank, 339 U.S. at 608. We remain mindful, however, that 

“‘[e]quivalence, in the patent law, is not the prisoner of a 

formula and is not an absolute to be considered in a 

vacuum.’” Warner-Jenkinson, 520 U.S. at 24-25 (quoting 

Graver Tank, 339 U.S. at 609). 

Saint-Gobain makes an interesting argument, not illogical, (and ably articulated by the dissent) regarding a 

correspondence between the nonobviousness of an accused 

product, as shown by its separate patentability, and its 

infringement of another patent under the doctrine of 

equivalents. However, we agree with Siemens that the 

district court did not legally err by instructing the jury 

that infringement in this case may be proved by a preponderance of the evidence. Patent infringement, 

whether literal or by equivalence, is an issue of fact, 

which the patentee must prove by a preponderance of the 

evidence. Cross Med. Prods., Inc. v. Medtronic Sofamor 
SIEMENS MEDICAL v. SAINT GOBAIN 12

Danek, Inc., 424 F.3d 1293, 1310 (Fed. Cir. 2005) (“To 

prove direct infringement, the plaintiff must establish by 

a preponderance of the evidence that one or more claims 

of the patent read on the accused device literally or under 

the doctrine of equivalents.”); see also Morton Int’l, Inc. v. 

Cardinal Chem. Co., 5 F.3d 1464, 1468 (Fed. Cir. 1993); 

SRI Int’l v. Matsushita Elec. Corp. of Am., 775 F.2d 1107, 

1123 (Fed. Cir. 1985) (en banc) (“The patentee bears the 

burden of proving infringement by a preponderance of the 

evidence.”). Saint-Gobain nonetheless insists that in one 

particular situation—where the purported equivalent is 

claimed in a separately issued United States patent—

proof of infringement by equivalence requires clear and 

convincing evidence. As we shall explain, however, we 

decline to inject Saint-Gobain’s proposed rule into the 

interstices of our longstanding equivalence doctrine 

jurisprudence. 

Saint-Gobain argues that Festo mandates an increased burden of proof in cases of separate patentability, 

but Festo did not involve this issue. In Festo, in the 

context of prosecution history estoppel as a legal limitation on the doctrine of equivalents, our sole consideration 

was whether an equivalent was unforeseeable as of the 

patent application’s filing date. Festo, 493 F.3d at 1377. 

Nonetheless, Saint-Gobain points out that, in rejecting 

one party’s proposed legal standard for foreseeability, we 

stated: 

We have not directly decided whether a device—

novel and separately patentable because of the incorporation of an equivalent feature—may be captured by the doctrine of equivalents, although we 

have held that when a device that incorporates 

the purported equivalent is in fact the subject of a 

separate patent, a finding of equivalency, while 

perhaps not necessarily legally foreclosed, is at 
13 SIEMENS MEDICAL v. SAINT GOBAIN

least considerably more difficult to make out. But 

there is a strong argument that an equivalent 

cannot be both non-obvious and insubstantial. 

Id. at 1379-80 (internal footnotes omitted). Saint-Gobain 

also relies upon the concurring opinion in Roton Barrier, 

Inc. v. Stanley Works, in which Judge Nies wrote that “a 

second patent, depending on its subject matter, may be 

relevant to the issue of whether the changes [in an accused device] are substantial,” and that “[a] substitution 

in a patented invention cannot be both nonobvious and 

insubstantial.” 79 F.3d 1112, 1128 (Fed. Cir. 1996) (Nies, 

J., additional views). 

These passages, however, cannot reasonably be read 

to require proof of equivalency by clear and convincing 

evidence in cases of separate patentability. Rather, these 

statements indicate that where, as here, the alleged 

equivalent is claimed in a separate patent, this fact, when 

weighed by the fact-finder together with all other relevant 

evidence, may make equivalency “considerably more 

difficult to make out” by a preponderance of the evidence. 

The issue of infringement by a separately patented 

equivalent was addressed in the Supreme Court decision 

of Sanitary Refrigerator Co. v. Winters, 280 U.S. 30 

(1929). In that case, the patent in suit, filed by Winters 

and Crampton, claimed an improved refrigerator door 

latch that automatically locked as the door closed. Id. at 

36-37. The allegedly infringing door latch was covered by 

a later-issued U.S. patent to Schrader. In its opinion, the 

Court first acknowledged that the accused device did not 

literally infringe the narrow claims of the Winters and 

Crampton patent. Id. at 41. The Court then proceeded to 

apply the function-way-result test to the accused device 

and found infringement by equivalence. Id. at 41-42. The 

Court held that infringement cannot be avoided in a 
SIEMENS MEDICAL v. SAINT GOBAIN 14

device that has “no substantial departure” from the 

claimed invention. Id. at 42. The Court further noted: 

“Nor is the infringement avoided . . . by any presumptive 

validity that may attach to the Schrader patent by reason 

of its issuance after the Winters and Crampton patent.” 

Id. at 43. The Court thus found equivalence in the face of 

separate patentability without imposing a heightened 

evidentiary burden. 

The passage in Festo relied on by Saint-Gobain includes citations of numerous cases in which we, like the 

Court in Sanitary Refrigerator, rejected arguments that 

separate patentability warrants anything more than 

consideration of this fact together with all others weighing for and against equivalency. Festo, 493 F.3d at 1379 

n.8 (citing Glaxo Wellcome, Inc. v. Andrx Pharms., Inc., 

344 F.3d 1226 (Fed. Cir. 2003); Hoechst Celanese, 78 F.3d 

1575; Nat’l Presto Indus. v. W. Bend Co., 76 F.3d 1185 

(Fed. Cir. 1996); Atlas Powder Co. v. E.I. du Pont De 

Nemours & Co., 750 F.2d 1569 (Fed. Cir. 1984)). 

In Hoechst Celanese, for example, the accused infringer argued that the fact that it “is practicing a process 

that is separately patentable . . . is presumptive evidence 

of non-infringement,” both literally and by equivalence. 

78 F.3d at 1582. We disagreed, noting that “[t]he fact of 

separate patentability presents no legal or evidentiary 

presumption of noninfringement.” Id. In Glaxo Wellcome, 

we vacated a district court’s grant of summary judgment 

of noninfringement, both literally and under the doctrine 

of equivalents. 344 F.3d at 1233. In doing so, we rejected 

the accused infringer’s argument that it did not infringe 

because its accused pharmaceutical formulation was 

separately patented. We explained that, “[a]lthough this 

fact may be weighed by the district court, particularly if 

there is an issue of ‘insubstantial’ change with respect to 
15 SIEMENS MEDICAL v. SAINT GOBAIN

equivalency, separate patentability does not automatically negate infringement.” Id. 

Moreover, in National Presto, we confirmed that “[t]he 

fact of separate patentability is relevant, and is entitled to 

due weight,” but does not confer any presumption of 

noninfringement; rather, “[s]uch evidence when present 

warrants consideration by the trier of fact, along with the 

other evidence of the differences and similarities of the 

patented and accused devices.” 76 F.3d at 1192. In Atlas 

Powder, we rejected the argument that the grant of a 

patent to an accused infringer constitutes a prima facie

determination of nonequivalence. 750 F.2d at 1580. 

Instead, we endorsed the view that “‘[p]atentable difference does not of itself tend to negative infringement.’” Id.

at 1581 (quoting Herman v. Youngstown Car Mfg. Co., 

191 F. 579, 585 (6th Cir. 1911)). 

None of these cases cited in Festo supports a requirement of proof of equivalency by clear and convincing 

evidence in cases involving separate patentability. Indeed, in other cases we have likewise indicated that 

separate patentability, while potentially relevant to the 

equivalence issue and deserving of due weight in the 

infringement analysis, does not merit a heightened evidentiary burden. See, e.g., Abraxis Biosci., 467 F.3d 1370, 

1382 (Fed. Cir. 2006) (affirming the district court’s finding 

of infringement by equivalence and stating that separate 

patentability of the accused pharmaceutical formulation 

did not outweigh substantial evidence of its equivalence); 

Fiskars, Inc. v. Hunt Mfg. Co., 221 F.3d at 1324 (holding 

that the trial court judge did not err by withholding 

evidence of separate patentability from the jury, because 

“it is well established that separate patentability does not 

avoid equivalency as a matter of law”); Zygo Corp. v. Wyko 

Corp., 79 F.3d 1563, 1570 (Fed. Cir. 1996) (“The nonobviousness of the accused device, evidenced by the grant of a 
SIEMENS MEDICAL v. SAINT GOBAIN 16

United States patent, is relevant to the issue of whether 

the change therein is substantial.”). 

Saint-Gobain argues that proof by clear and convincing evidence is required on the facts of this case, because 

the jury’s finding of equivalence “constructively invalidates” the ’420 patent. We disagree with Saint-Gobain’s 

reasoning in several respects. First, patents are afforded 

a statutory presumption of validity under 35 U.S.C. § 282, 

and overcoming this presumption requires proof by clear 

and convincing evidence. See, e.g., Pfizer, Inc. v. Apotex, 

Inc., 480 F.3d 1348, 1359-60 (Fed. Cir. 2007); Hybritech 

Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1375 

(Fed. Cir. 1986). Even if equivalence were relevant to 

obviousness, a point on which we need not and do not 

express an opinion, the jury properly found infringement 

under the equivalence doctrine by only a preponderance of 

the evidence. Thus, ipso facto, the jury’s finding could not 

invalidate the ’420 patent, constructively or otherwise. 

Moreover, with regard to Saint-Gobain’s contention 

that equivalence is tantamount to obviousness, we disagree. The two legal principles require different analytical frameworks. The doctrine of equivalents, although 

“not the prisoner of a formula,” Graver Tank, 339 U.S. at 

609, typically involves application of the insubstantial 

differences test, usually via the function-way-result test. 

Obviousness, by contrast, requires analysis under the four 

Graham factors. Graham v. John Deere Co., 383 U.S. 1, 

17-18 (1966); accord KSR Int’l Co. v. Teleflex Inc., 550 

U.S. 398, 406-07 (2007). Unlike equivalence, an obviousness inquiry may center on, for example, objective evidence of commercial success, e.g., Symbol Techs., Inc. v. 

Opticon, Inc., 935 F.2d 1569, 1579 (Fed. Cir. 1991), or on 

the level of predictability in the art, e.g., SanofiSynthelabo v. Apotex, Inc., 550 F.3d 1075, 1089 (Fed. Cir. 

2008). Indeed, although we express no view regarding the 
17 SIEMENS MEDICAL v. SAINT GOBAIN

validity of the ’420 patent, we note that Saint-Gobain’s 

“constructive invalidity” argument fails to account for the 

commercial success of its own 10% Y LYSO crystals or the 

unpredictability in the field of crystallization. See, e.g., 

id. (noting experts’ agreement regarding the unpredictability of crystallization). 

Furthermore, the time frames of the two inquiries differ. Under the doctrine of equivalents, “the proper time 

for evaluating equivalency . . . is at the time of infringement, not at the time the patent was issued,” WarnerJenkinson, 520 U.S. at 37, yet obviousness asks whether a 

claimed invention “would have been obvious at the time 

the invention was made,” 35 U.S.C. § 103(a). These and 

other differences between equivalence and obviousness 

undermine Saint-Gobain’s theory of “constructive invalidation.” 

Saint-Gobain’s professed justification for a clear and 

convincing standard also overlooks an important distinction regarding claim scope. The jury’s infringement 

verdict indicates only that Saint-Gobain’s marketed 10% 

Y LYSO crystals are equivalent to the LSO crystals of 

claim 1 or 2 of the ’080 patent. JMOL Opinion at 308-09. 

Importantly, the verdict does not imply equivalence 

between the ’080 patent and the full claim scope of the 

’420 patent—which, as noted above, covers LYSO crystals 

ranging from 0.01% Y to 99.99% Y. An invalidity analysis 

under § 103 requires a comparison between the prior art 

and the claimed “subject matter as a whole, not separate 

pieces of the claim.” Sanofi-Synthelabo, 550 F.3d at 1086. 

The jury made no such comparison under the doctrine of 

equivalents, further highlighting the fallacy of SaintGobain’s premise that the ’420 patent was “constructively 

invalidated.” 
SIEMENS MEDICAL v. SAINT GOBAIN 18

In summary, we agree with neither the proposed rule 

nor the rationale proffered by Saint-Gobain. We, like the 

district court, “decline[] to be the first (and only) court to 

depart from an extended history of patent infringement 

jurisprudence applying the preponderance of the evidence 

standard.” JMOL Opinion at 310. We therefore hold 

that, even though the alleged equivalent in this case was 

separately patented, the district court did not legally err 

by instructing the jury that infringement under the 

doctrine of equivalents may be proved by a preponderance 

of the evidence.4

2. Presumption of Validity of the ’420 Patent 

Saint-Gobain also argues that, because the validity of 

the ’420 patent was at issue in this case, the district court 

erroneously denied its proposed jury instruction that the 

’420 patent was entitled to a presumption of validity. 

Saint-Gobain reasons that because the ’420 patent issued 

after the patent examiner considered the ’080 patent as 

prior art, 10% Y LYSO crystals are necessarily nonobvious and patentable over LSO crystals. Saint-Gobain 

equates the issuance of the ’420 patent to a determination 

by the Patent and Trademark Office (“PTO”) that 10% Y 

LYSO and LSO crystals are not substantially equivalent. 

Thus, Saint-Gobain argues, instructing the jury that the 

’420 patent is presumed valid “would have made proof of 

equivalence more difficult, as Festo requires.” Opening 

Br. of Def.-Appellant Saint-Gobain at 35. Saint-Gobain 

further argues that at trial Siemens challenged the validity and enforceability of the ’420 patent, thus heightening 

the need for its proposed jury instruction. 

 4 Because Saint-Gobain does not appeal the jury’s 

finding by a preponderance of the evidence that SaintGobain infringed the ’080 patent under the doctrine of 

equivalents, we do not address that issue in our opinion. 
19 SIEMENS MEDICAL v. SAINT GOBAIN

Siemens responds that the validity of the ’420 patent 

was not at issue in this case and therefore that the presumption of validity was not applicable to the case. 

Siemens also stresses that the ’420 patent was admitted 

into evidence, that the jury was informed during the trial 

that all patents are presumed valid, and that the district 

court permitted Saint-Gobain to reiterate this point 

during its closing arguments. Siemens argues that, in 

connection with Saint-Gobain’s defense to willfulness and 

the intent prong to inducement, Siemens was justified in 

probing the circumstances under which Saint-Gobain 

itself believed the ’420 patent might be invalid. Accordingly, Siemens asserts that the district court properly 

exercised its discretion by declining to instruct the jury 

regarding the presumption of validity of the ’420 patent. 

We conclude that the district court’s decision not to 

provide separate instructions to the jury about the presumption of validity did not “clearly mislead the jury.” 

DSU Med., 471 F.3d at 1304 (internal quotation marks 

omitted). Patent validity was not an issue before the jury: 

the validity of the ’080 patent was not challenged at trial, 

and, as we explained above, the verdict of infringement by 

equivalence in no way affected the validity of the ’420 

patent. As the district court correctly noted, Siemens 

probed aspects of the ’420 patent in connection with 

Saint-Gobain’s license defense to willfulness, but “appropriately stopped short of directly challenging the validity 

of the ’420 patent.” JMOL Opinion at 313. Thus, the 

requested instruction was not directly relevant to the 

issues before the jury. 

To the extent that the presumed validity of the ’420 

patent made a finding of infringement by equivalence 

more difficult, as Saint-Gobain argues, the jury had notice 

of the presumption. During the trial, the jury viewed a 

video providing an overview of the patent system, which 
SIEMENS MEDICAL v. SAINT GOBAIN 20

stated in part that “[t]o prove that a patent is invalid, the 

law requires a higher standard of proof, since the PTO is 

presumed to have done its job correctly.” Id.; J.A. 652. In 

its closing arguments, Saint-Gobain affirmatively stated 

at least three times on the record that the ’420 patent is 

presumed valid. JMOL Opinion at 312; J.A. 1763-88. In 

its final instructions, the district court invited the jury as 

part of its equivalence analysis to “consider that [SaintGobain] obtained the license under the [’420] patent, 

which may be some evidence that the differences between 

the 10% Y LYSO crystal[s] and the claimed LSO crystal[s] 

are substantial.” JMOL Opinion at 309. We therefore 

agree with the district court that the jury was not clearly 

misled by the court’s ruling excluding a specific jury 

instruction on the validity of the ’420 patent. 

B. Exclusion of Evidence 

We review a district court’s decision to exclude evidence under the law of the regional circuit. Del. Valley 

Floral Grp., Inc. v. Shaw Rose Nets, LLC, 597 F.3d 1374, 

1379 (Fed. Cir. 2010). The Third Circuit reviews a district court’s decision to exclude evidence for abuse of 

discretion. Glass v. Phila. Elec. Co., 34 F.3d 188, 191 (3d 

Cir. 1994); see also Rhodia Chimie v. PPG Indus., Inc., 

402 F.3d 1371, 1376-77 (Fed. Cir. 2005). “A ruling excluding evidence under Rule 403 is accorded particular deference, and . . . it may not be reversed unless the 

determination is arbitrary and irrational.” In re Paoli 

R.R. Yard PCB Litig., 113 F.3d 444, 453 (3d Cir. 1997) 

(internal quotation marks omitted). An erroneous evidentiary ruling “is harmless only if it is highly probable that 

the error did not affect the outcome of the case.” Glass, 34 

F.3d at 191 (internal quotation marks omitted). 
21 SIEMENS MEDICAL v. SAINT GOBAIN

1. The ’489 Patent 

Saint-Gobain argues that the district court erred by 

excluding the ’489 patent from evidence. Saint-Gobain 

contends that the ’489 patent demonstrates the patentability, and therefore the nonequivalence, of 10% Y 

LYSO. Saint-Gobain further contends that the ’489 

patent served to rebut Siemens’ attack on the validity of 

the ’420 patent. 

In response, Siemens argues that, because SaintGobain failed to raise its relevance argument regarding 

the ’489 patent at the district court, this argument is now 

waived. Siemens also contends that the district court 

properly excluded the ’489 patent, because its potential to 

confuse the jury outweighed its potential relevance. 

Finally, Siemens argues that any error associated with 

the court’s ruling is harmless, because the jury was informed of the existence and content of the ’489 patent. 

We agree with Siemens that the district court did not 

abuse its discretion by excluding the ’489 patent from 

evidence. At trial, Saint-Gobain sought to introduce the 

’489 patent only in connection with its license defense to 

Siemens’ claim of willful infringement. JMOL Opinion at 

311-12. As the district court noted, Saint-Gobain “did not 

offer the ’489 patent for a disclosure of LYSO crystals.” 

Id. at 312. In response to Saint-Gobain’s request, the 

district court admitted testimony regarding SaintGobain’s license of the ’489 patent and the license itself, 

but excluded the ’489 patent under Rule 403, reasoning 

that “there is a high likelihood of confusion to the jury” in 

admitting the abandoned patent. Id. 

Only after trial did Saint-Gobain argue for the first 

time that the ’489 patent should have been admitted for 

its relevance to the patentability of LYSO crystals. Id. 

Because at the time of its evidentiary ruling the district 
SIEMENS MEDICAL v. SAINT GOBAIN 22

court was not informed of Saint-Gobain’s view that the 

’489 patent was relevant to its equivalence argument, 

Saint-Gobain cannot now attack the court’s evidentiary 

ruling on this basis. See Old Chief v. United States, 519 

U.S. 172, 182 n.6 (1997) (“It is important that a reviewing 

court evaluate the trial court's decision from its perspective when it had to rule and not indulge in review by 

hindsight.”). Thus, the district court’s ruling under Rule 

403 was not arbitrary and irrational. 

We also agree with Siemens that any error associated 

with the district court’s ruling was harmless. The ’489 

patent, which was abandoned following the interference 

with the ’420 patent, was not (and could not have been) 

asserted in this case. Even if Saint-Gobain had presented 

its relevance arguments prior to the court’s evidentiary 

ruling, the ’489 patent would largely have been cumulative of evidence already of record, including the ’420 

patent. Id. at 312. Both the ’420 and ’489 patents disclose and claim substantially the same invention—hence 

the interference proceeding. Id. at 308 n.3. During the 

trial, the jury was informed of the existence and content 

of the ’489 patent, including Saint-Gobain’s efforts to 

obtain a license (id. at 312; J.A. 940; J.A. 1244-45; J.A. 

1261-62), and Saint-Gobain presented to the jury a timeline that contained both a text reference to the ’489 patent’s issuance and an image of the patent itself (J.A. 

2032). For these reasons we conclude that it is “highly 

probable” that any error associated with the exclusion of 

the ’489 patent did not affect the outcome of this case, and 

therefore that any error in the district court’s evidentiary 

ruling was harmless. Glass, 34 F.3d at 191. 

2. Expert Testimony 

Saint-Gobain argues that the district court abused its 

discretion by granting Siemens’ motion to exclude certain 
23 SIEMENS MEDICAL v. SAINT GOBAIN

testimony of Saint-Gobain’s expert, Dr. McClellan, regarding the use of LYSO in applications other than PET. 

Saint-Gobain argues that the ’080 patent claims a scintillator without regard to its particular application, and 

therefore that it was inappropriate to limit the substantial equivalence inquiry solely to PET scan applications. 

Saint-Gobain also points out that the importance of 

different scintillation properties can vary dramatically by 

application, so the district court could not properly determine substantial equivalence by examining only a single 

application. 

Siemens responds that the district court did not restrict Dr. McClellan from testifying on the scintillation 

properties Saint-Gobain now complains were excluded; 

the court only prevented Dr. McClellan from going beyond 

his expert disclosures or discussing matters not disclosed 

to Siemens during discovery. Siemens asserts that the 

court’s ruling imposed sensible limitations on expert 

testimony under the Federal Rules of Civil Procedure. 

Siemens contends that Dr. McClellan in fact testified at 

length about many of the scintillation properties that 

Saint-Gobain claims were excluded. Siemens further 

contends that Saint-Gobain waived the arguments it now 

makes on appeal by failing to make a specific proffer of 

the testimony that Dr. McClellan would have presented at 

trial. 

The district court did not abuse its discretion in its 

ruling regarding the expert testimony of Dr. McClellan. 

We agree that the district court “did not render a specific 

ruling regarding the substance of Dr. McClellan’s testimony,” JMOL Opinion at 313, but rather imposed sensible limitations on proposed testimony based upon 

undisclosed data and information. In its evidentiary 

ruling, the district court noted that Dr. McClellan’s experience with LSO and LYSO resulted from studies he 
SIEMENS MEDICAL v. SAINT GOBAIN 24

performed as a government contractor at the Los Alamos 

National Laboratory (“LANL”). Siemens Med. Solutions 

USA, Inc. v. Saint-Gobain Ceramics & Plastics, Inc., 2008 

WL 3862091, at *1 (D. Del. Aug. 20, 2008) (“Evidence 

Order”). Because his research involved national security 

matters, Dr. McClellan was unable to use any workrelated materials in the litigation or to produce any LANL 

documents during discovery. Id. The court expressed 

concern that, without any ability for Siemens to examine 

the studies that formed the basis of Dr. McClellan’s 

opinions, “there is clearly no principled way to test his 

recollection and opinion.” Id. 

The district court further noted in its evidentiary ruling that, although there were documents at LANL relating to the studies referenced in Dr. McClellan’s expert 

report, he did not review these materials to refresh his 

recollection when preparing his report. Id. The court 

thus identified a “serious question of whether his recollection of data generated several years ago can possibly 

constitute a sufficient basis for an expert opinion” under 

Rule 702 of the Federal Rules of Evidence. Id. For these 

reasons, the court granted Siemens’ motion to exclude 

portions of Dr. McClellan’s testimony that were not disclosed in discovery—i.e., it ruled that Dr. McClellan could 

not testify on matters not disclosed in his expert report or 

deposition, and he could not rely on testing that was not 

disclosed to Siemens during discovery. Id.; JMOL Opinion at 314. 

The court’s evidentiary ruling was justified and well 

reasoned. The court’s judgment comports with Fed. R. 

Civ. P. 26(a)(2)(B)(i)-(ii), which requires experts to provide 

a written report containing “a complete statement of all 

opinions the witness will express and the basis and reasons for them” and “the facts or data considered by the 

witness in forming them.” As the Advisory Committee 
25 SIEMENS MEDICAL v. SAINT GOBAIN

Note accompanying the 1993 amendments to Rule 26 

explains: “Given this obligation of disclosure, litigants 

should no longer be able to argue that materials furnished 

to their experts to be used in forming their opinions—

whether or not ultimately relied upon by the expert—are 

privileged or otherwise protected from disclosure when 

such persons are testifying or being deposed.” Fed. R. 

Civ. P. 26 advisory committee’s note. 

Rule 26, therefore, “proceeds on the assumption that 

fundamental fairness requires disclosure of all information supplied to a testifying expert in connection with his 

testimony.” In re Pioneer Hi-Bred Int’l, Inc., 238 F.3d 

1370, 1375 (Fed. Cir. 2001). We agree with the district 

court that “the fundamental principle of fairness” supports its sensible limitations on Dr. McClellan’s testimony, as Siemens had “no principled way to test his 

recollection and opinion.” Evidence Order at *1. 

The court’s ruling further complies with Fed. R. Civ. 

P. 37(c)(1), which states that, if a party fails to comply 

with Rule 26(a), “the party is not allowed to use that 

information or witness to supply evidence on a motion, at 

a hearing, or at a trial, unless the failure was substantially justified or is harmless.” Saint-Gobain does not 

argue that its failure to disclose was substantially justified or harmless. Thus, the district court did not abuse its 

discretion by ruling that Dr. McClellan could not testify 

on matters not disclosed in his expert report or deposition, 

and that he could not rely on testing that was not disclosed to Siemens during discovery. 

C. Lost Profits Damages 

Whether lost profits are legally compensable in a particular situation is a question of law that we review de

novo. Poly-Am., L.P. v. GSE Lining Tech., Inc., 383 F.3d 

1303, 1311 (Fed. Cir. 2004) (citing Rite-Hite Corp. v. 
SIEMENS MEDICAL v. SAINT GOBAIN 26

Kelley Co., 56 F.3d 1538, 1544 (Fed. Cir. 1995) (en banc)). 

“To recover lost profits, the patent owner must show 

causation in fact, establishing that but for the infringement, he would have made additional profits.” Wechsler 

v. Macke Int’l Trade, Inc., 486 F.3d 1286, 1293 (Fed. Cir. 

2007) (internal quotation marks omitted). Thus, in general, “the patent owner must prove (1) a demand for the 

patented product, (2) an absence of acceptable noninfringing substitutes, (3) the manufacturing and marketing 

capability to exploit the demand, and (4) the amount of 

profit the patent owner would have made.” Cohesive 

Techs., Inc. v. Waters Corp., 543 F.3d 1351, 1373 (Fed. 

Cir. 2008) (quoting Standard Havens Prods., Inc. v. 

Gencor Indus., Inc., 953 F.2d 1360, 1373 (Fed. Cir. 1991)); 

see also Panduit Corp. v. Stahlin Bros. Fibre Works, Inc., 

575 F.2d 1152, 1156 (6th Cir. 1978). 

Saint-Gobain argues that the court erred by allowing 

the jury to consider lost profits damages, because Siemens 

failed to demonstrate that it would have made SaintGobain’s sales “but for” the infringement. Saint-Gobain 

does not dispute that Philips’ LYSO scanner competed 

with Siemens’ LSO scanner. However, Saint-Gobain cites 

evidence that General Electric (“GE”) sold scanners 

containing bismuth germinate (“BGO”) scintillator crystals, JMOL Opinion at 315, and argues that the market 

thus consisted of three competing sellers: Siemens, 

Philips, and GE. Saint-Gobain contends that GE’s BGO 

scanners competed with Siemens’ LSO scanners, because 

Siemens lost PET scanner sales to GE. Saint-Gobain also 

argues that it could have made and sold scanners containing lanthanum bromide (LaBr3) scintillator crystals, 

which were an available, noninfringing substitute for LSO 

crystals.

Siemens argues in response that sufficient evidence 

supported submitting the question of lost profits to the 
27 SIEMENS MEDICAL v. SAINT GOBAIN

jury and the jury’s award. Siemens argues that, but for 

the infringement, it would have made the sales made by 

Saint-Gobain. Siemens further argues that substantial 

evidence supports a high-end, two-supplier PET market 

consisting of Siemens’ LSO scanners and Saint-Gobain’s 

LYSO scanners. Siemens contends that GE’s BGO scanners were cheaper and generally inferior to LSO and 

LYSO, and therefore were not competitive. In addition, 

Siemens argues that it is irrelevant whether it lost sales 

to GE, because the issue is what Philips’ customers would 

have done had Saint-Gobain’s infringement not occurred. 

Lastly, Siemens argues that the jury had ample supporting evidence to believe Siemens’ claim that LaBr3 was not 

available and was an unacceptable alternative to LSO 

and 10% Y LYSO.

We perceive no legal error in the district court’s decision to permit the jury to award lost profits damages. On 

appeal, the dispute between Saint-Gobain and Siemens 

over lost profits centers on (1) whether there existed a 

two-supplier, high-end market for PET scanners, and (2) 

whether LaBr3 scanners were available, acceptable noninfringing alternatives to LSO scanners. On both issues, 

Siemens presented substantial evidence to support a lost 

profits award. 

Accurately identifying a two-supplier market “‘requires an analysis which excludes alternatives to the 

patented product with disparately different prices or 

significantly different characteristics.’” Micro Chem., Inc. 

v. Lextron, Inc., 318 F.3d 1119, 1124 (Fed. Cir. 2003) 

(quoting Crystal Semiconductor Corp. v. TriTech Microelecs. Int’l, Inc., 246 F.3d 1336, 1356 (Fed. Cir. 2001)). 

Here, the parties disputed whether GE’s BGO scanner 

was an alternative to the LSO and LYSO scanners such 

that a three-supplier market existed. The district court 

summarized the ample evidence that BGO was generally 
SIEMENS MEDICAL v. SAINT GOBAIN 28

inferior to LSO with respect to important scintillator 

properties, including light output and decay time. JMOL 

Opinion at 315-16. In addition, the district court credited 

the testimony of Siemens’ head of marketing and sales, 

who testified that BGO-based scanners do not compete 

with Siemens’ LSO-based scanners in the high-end PET 

scanner market, id. at 316, because BGO scanners, with 

their relatively poor image quality, were purchased by 

“customers that are extremely tight in their budgets,” 

whereas the more expensive LSO scanners were purchased by customers seeking the “highest performance 

and high technology.” J.A. 985. 

The district court also credited Saint-Gobain’s own 

documents and the testimony of Saint-Gobain’s witnesses, 

which consistently described a two-supplier “high-end 

PET scanner market” consisting only of LSO and LYSO 

scanners. JMOL Opinion at 316. Saint-Gobain is correct 

in arguing that its damages expert provided testimony 

indicating that Siemens lost some sales to GE’s BGO 

scanners during the relevant time period. However, as 

the district court correctly noted, there was ample evidence for a reasonable jury to infer the existence of a twosupplier market for high-end PET scanners consisting of 

Siemens’ LSO scanners and Philips’ LYSO scanners. Id. 

The parties also dispute whether LaBr3-based scanners were available substitutes. To be “available,” an 

acceptable noninfringing substitute must have been 

“available or on the market” at the time of infringement. 

Grain Processing Corp. v. Am. Maize-Prods. Co., 185 F.3d 

1341, 1349 (Fed. Cir. 1999) (emphasis and internal quotation marks omitted). A substitute need not be on sale at 

the time of infringement, but if the substitute cannot be 

commercialized “readily,” then it is not available for 

purposes of a lost profits determination. See Micro 

Chem., 318 F.3d at 1123; cf. Grain Processing, 185 F.3d at 
29 SIEMENS MEDICAL v. SAINT GOBAIN

1354. At trial, the parties disputed whether LaBr3 was an 

available alternative to LSO, and on appeal Saint-Gobain 

points to evidence that it asserts supports the availability 

of LaBr3. Notwithstanding, the evidence reasonably 

supported a finding that LaBr3 was not an available 

alternative. As the district court noted, evidence showed 

that LaBr3 was at least a year and a half behind LYSO in 

development. JMOL Opinion at 317. In addition, SaintGobain stipulated that there were no commercial PET 

scanners sold on the market using a LaBr3 scintillation 

crystal. J.A. 1111. The court also cited evidence demonstrating several disadvantages inherent to LaBr3, including its inferior density and hygroscopicity. JMOL 

Opinion at 317. 

Because of the substantial evidence in the record supporting the elements required for an award of lost profits, 

we find no legal error in the district court’s decision to 

permit the jury to consider lost profits damages.

D. Cross-Appeal of the Reduction of the Jury’s Damage 

Award 

Siemens cross-appeals the district court’s decision to 

reduce the jury’s damages award. We review the decision 

of a district court to reduce a jury’s damages award under 

the law of the regional circuit. Minks v. Polaris Indus., 

Inc., 546 F.3d 1364, 1369-70 (Fed. Cir. 2008); Tronzo v. 

Biomet, Inc., 236 F.3d 1342, 1346 (Fed. Cir. 2001). The 

Third Circuit reviews a discretionary reduction in a jury 

award for abuse of discretion. Cortez v. Trans Union, 

LLC, 617 F.3d 688, 716 (3d Cir. 2010); see also Spence v. 

Bd. of Educ. of the Christina Sch. Dist., 806 F.2d 1198, 

1201 (3d Cir. 1986) (“[A trial judge’s determination] that a 

decision of the jury is clearly unsupported and/or excessive. . . . falls within the discretion of the trial judge, 

whose decision cannot be disturbed by this court absent a 
SIEMENS MEDICAL v. SAINT GOBAIN 30

manifest abuse of discretion.”). “The trial judge is in the 

best position to evaluate the evidence and assess whether 

the jury’s verdict is rationally based.” Rivera v. V.I. 

Housing Auth., 854 F.2d 24, 27 (3d Cir. 1988). Accordingly, the scope of review “is exceedingly narrow.” Cortez, 

617 F.3d at 719. 

Siemens argues that substantial evidence supports 

the jury’s full award of damages. Specifically, Siemens 

contends that there was sufficient circumstantial evidence 

that Philips either had arranged to sell or would in fact 

sell all 79 scanners following their manufacture. Siemens 

argues in the alternative that the court erred by not 

awarding at least reasonable royalty damages for the 

remaining 18 scanners, because evidence showed that 

these 18 scanners were at least made, if not sold. Siemens thus argues that the district court erred by failing 

to consider that, under 35 U.S.C. § 271, it is an act of 

infringement to make, use, or offer to sell a patented 

invention, even if the product is not actually sold. 

Saint-Gobain responds that the court correctly reduced the jury’s damages award, because, as the district 

court determined, the evidence is “wholly speculative” 

regarding the sale of the additional 18 scanners. In 

addition, Saint-Gobain argues that Siemens did not assert 

a right to a reasonable royalty before the district court, so 

this argument is now waived on appeal. Finally, SaintGobain argues that the evidence does not support a 

finding that the 18 scanners’ worth of crystals were 

actually used to make scanners. 

We conclude that the district court did not abuse its 

discretion in reducing the jury’s damages award regarding lost profits on the additional 18 scanners. As discussed above, to recover lost profits damages, “the 

patentee must show a reasonable probability that, ‘but 
31 SIEMENS MEDICAL v. SAINT GOBAIN

for’ the infringement, it would have made the sales that 

were made by the infringer.” Rite-Hite, 56 F.3d at 1545. 

Here, the parties do not dispute that Saint-Gobain delivered 79 scanners’ worth of crystals to Philips, and that 

Philips made and sold at least 61 scanners. JMOL Opinion at 318. Rather, the dispute on appeal centers on 

whether Philips actually manufactured and sold the 

additional 18 scanners. 

As Siemens itself acknowledges, the only “evidence” of 

infringing sales of the 18 scanners was (1) Saint-Gobain’s 

delivery of 79 scanners’ worth of crystals to Philips, and 

(2) the testimony of Philips’ designated corporate representative, who agreed that “it’s not in Philips’ interest to 

hold a lot of inventory of crystals” and that “[Philips 

doesn’t] want to buy all of [its] supplies way in advance of 

when [it] need[s] them.” JMOL Opinion at 318; J.A. 1004. 

As the district court correctly found, this evidence indicates that Philips generally did not stockpile crystals and 

thus had incorporated them into infringing scanners—i.e., 

that Philips made the additional 18 scanners—but the 

evidence does not suggest that Philips sold the additional 

18 scanners prior to the expiration of the ’080 patent. 

JMOL Opinion at 319. Thus, with regard to the additional 18 scanners, there is no proof of “sales that were 

made by the infringer.” Rite-Hite, 56 F.3d at 1545. We 

therefore agree with Saint-Gobain that the district court 

did not abuse its discretion by reducing the jury’s damages award to account for the lack of substantial evidence 

supporting lost profits damages associated with the 

additional 18 scanners. 

However, we agree with Siemens that the court erred 

by failing to consider any damages on the additional 18 

scanners. A district court abuses its discretion when it 

commits legal error in its award of damages. State Indus., Inc. v. Mor-Flo Indus., Inc., 883 F.2d 1573, 1577 
SIEMENS MEDICAL v. SAINT GOBAIN 32

(Fed. Cir. 1989). Under 35 U.S.C. § 271, a party infringes 

a patent by contributing to or inducing another party to 

make, use, offer to sell, or sell a patented invention in the 

United States. In addition, under 35 U.S.C. § 284, “the 

floor for a damage award is no less than a reasonable 

royalty . . . and the award may be split between lost 

profits as actual damages to the extent they are proven 

and a reasonable royalty for the remainder.” Id.; accord

Rite-Hite, 56 F.3d at 1545. 

Here, the jury determined that Saint-Gobain infringed the ’080 patent by inducing and contributing to 

Philips’ infringement. JMOL Opinion at 309. The district court correctly noted that substantial evidence 

supported the conclusion that Philips made the additional 

18 scanners. Id. at 319. One who “makes” a patented 

invention without authorization infringes the patent. 35 

U.S.C. § 271(a) (2006). Yet, after eliminating the jury’s 

lost profits award on these 18 scanners, the district court 

failed to consider whether any “damages adequate to 

compensate for the infringement” were owed to Siemens. 

35 U.S.C. § 284 (2006); see also JMOL Opinion at 319. If 

district court eliminates a lost profits award with regard 

to a portion of infringing devices, the court must then 

determine an appropriate measure of damages for that 

portion. Crystal Semiconductor, 246 F.3d at 1355. Overlooking the requirement of 35 U.S.C. § 284 is legal error. 

Id. 

Here, the court abused its discretion by failing to determine a reasonable royalty for the remaining 18 scanners. We are not persuaded by Saint-Gobain’s arguments 

that Siemens waived its right to reasonable royalty damages. The jury heard testimony from both parties’ damages experts on the subject of reasonable royalties. The 

jury was also instructed on reasonable royalty damages. 

In opposition to Saint-Gobain’s motion for JMOL, Sie-
33 SIEMENS MEDICAL v. SAINT GOBAIN

mens pointed out that a patent is infringed by making, 

using, and selling the invention, and that the jury’s award 

was likely a combination of both lost profits and a reasonable royalty. Moreover, Saint-Gobain’s own damages 

expert testified that, in the event that Saint-Gobain is 

found to infringe, at least a reasonable royalty would be 

owed on all 79 scanners, including the additional 18 

scanners that were not sold by Philips. J.A. 1632-33. 

We therefore remand to the district court so that the 

court may determine a reasonable royalty for the additional 18 scanners, to be added to the award of 

$44,937,545 in lost profits for 61 scanners that were sold. 

In determining the reasonable royalty, the district court 

may rely on the present record if deemed adequate, or 

may elect to receive additional expert testimony on what 

royalty would be reasonable under the circumstances. 35 

U.S.C. § 284 (2006). 

CONCLUSION

The district court’s judgment entered in favor of Siemens is affirmed. However, we vacate the damages 

award and remand for the court to consider a reasonable 

royalty for the additional 18 infringing scanners, to be 

added to the $44,937,545 in lost profits for the 61 scanners that were sold. 

AFFIRMED IN PART, VACATED IN PART, AND 

REMANDED 

COSTS

Costs to Siemens. 
United States Court of Appeals 

for the Federal Circuit 

__________________________ 

SIEMENS MEDICAL SOLUTIONS USA, INC., 

Plaintiff-Cross Appellant, 

v. 

SAINT-GOBAIN CERAMICS & PLASTICS, INC., 

Defendant-Appellant. 

__________________________ 

2010-1145, -1177 

__________________________ 

Appeals from the United States District Court for the 

District of Delaware in case no. 07-CV-0190, Judge Sue L. 

Robinson. 

__________________________ 

PROST, Circuit Judge, dissenting. 

I respectfully dissent because, in my view, there is a 

tension between the equivalence and nonobviousness 

inquiries presented in this appeal. 

As it has here, this tension comes to light when a patentee asserts the doctrine of equivalents against some 

feature that the U.S. Patent and Trademark Office 

(“PTO”) declared to be a point of novelty in a separate 

patent. To prevail on equivalence, the patentee must 

prove that the feature is insubstantially different from 

the limitations of his asserted claim. Graver Tank & Mfg. 

Co. v. Linde Air Prods. Co., 339 U.S. 605, 610 (1950); 
SIEMENS MEDICAL v. SAINT GOBAIN 2

accord Chiuminatta Concrete Concepts, Inc. v. Cardinal 

Indus., Inc., 145 F.3d 1303, 1310 (Fed. Cir. 1998). In an 

ordinary case, we would say that the patentee’s efforts to 

prove infringement will not be hindered by an accused 

infringer’s proof of separate patenting. Atlas Powder Co. 

v. E.I. du Pont De Nemours & Co., 750 F.2d 1569, 1581 

(Fed. Cir. 1984). The equivalence analysis, however, 

presents a unique circumstance. 

Where equivalence is used against a feature that is 

separately patented, the patentee’s attempts to show that 

the feature is insubstantially different from the asserted 

patent crash into the well-settled presumption that 

patents are nonobvious over the prior art. See Zygo Corp. 

v. Wyko Corp., 79 F.3d 1563, 1570 (Fed. Cir. 1996). When 

a fact finder concludes that a feature is “insubstantially 

different” from a patent, how are we then to view the 

validity of the patent putatively establishing that same 

feature as “nonobvious”? 

Examining the legal standards underlying obviousness and equivalence only emphasizes the potential for 

overlap. The Supreme Court has instructed us that four 

factors should be used in assessing obviousness: (1) the 

scope and content of the prior art, (2) the differences 

between the prior art and the claims, (3) the level of 

ordinary skill in the art, and (4) secondary considerations 

such as commercial success, unexpected results, and longfelt need. Graham v. John Deere Co. of Kan. City, 383 

U.S. 1, 17–18 (1966); accord Syntex (U.S.A.) LLC v. Apotex, Inc., 407 F.3d 1371, 1378 (Fed. Cir. 2005). These 

factors are intended to guide judges and juries in determining whether a hypothetical “skilled artisan” would 

have viewed the claimed invention as one that was suggested in a straightforward way by the prior art and the 

general level of knowledge in the field. KSR Int’l Co. v. 
3 SIEMENS MEDICAL v. SAINT GOBAIN

Teleflex Inc., 550 U.S. 398, 417–18 (2007). The caselaw is 

replete with courts elaborating these standards in the 

hope of making this difficult analysis as fair and straightforward as possible. 

The standard for equivalence—“insubstantial difference”—has also been well-explored. If a skilled artisan, at 

the time of the accused infringement, viewed a substitution to a patented invention as insubstantially different 

from the claim, the substitution is equivalent and infringement may arise. Graver Tank, 339 U.S. at 610; 

Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 

U.S. 17, 40 (1997). The doctrine prevents accused infringers from evading liability by making “trivial” changes 

to the patented invention. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 733 (2002). That 

a substitution is “trivial” or “insubstantially different” 

may be proved by showing that the substitution performs 

the same function, in the same way, with the same result 

as the technology of the claim limitation. Catalina Marketing Int’l, Inc. v. Coolsavings.com, Inc., 289 F.3d 801, 

813 (Fed. Cir. 2002). 

The majority reasons that these two tests, obviousness and equivalence, are separate from one another. But 

while the details differ, I find there is an inevitable area 

of overlap. Assume a court, applying Graver Tank and its 

progeny, found that to a person of skill in the art a substitution was insubstantially different from a claim limitation. Having so found, and setting aside (for the moment) 

consideration of the time frames at which obviousness 

and equivalence are assessed, the court would need only a 

further finding that the skilled artisan had some reason 

to make the substitution to find the limitation obvious 
SIEMENS MEDICAL v. SAINT GOBAIN 4

under Graham and KSR.1 This is not a high bar. For a 

truly insubstantial change, the predictability of outcome 

when substituting the one for the other suggests that a 

reason to combine will be easy to prove. Rothman v. 

Target Corp., 556 F.3d 1310, 1319 (Fed. Cir. 2009). 

I therefore disagree with the majority in that I do not 

view it acceptable to leave the fact-finder—here, a jury—

without instruction on how it might navigate the equivalence inquiry without undermining the presumption of 

nonobviousness that we must accord issued patents. 

Judge Nies anticipated the challenge we face when 

she wrote, “a substitution in a patented invention cannot 

be both nonobvious and insubstantial.” Roton Barrier, 

Inc. v. Stanley Works, 79 F.3d 1112, 1128 (Fed. Cir. 1996) 

(Nies, J., Additional Views). A similar concern was voiced 

 1 In the past, some litigants attempted to avoid 

this second step entirely, and prove “anticipation by 

equivalents.” This court rejected that theory, holding that 

a claim is invalid under § 102 if and only if each and every 

limitation of the claim is literally present in a single prior 

art reference. But while it rejected “anticipation by 

equivalents,” this court noted that the doctrine of equivalents was, “if one wished to draw a parallel, . . . somewhat 

akin to obviousness.” Lewmar Marine, Inc. v. Barient, 

Inc., 827 F.2d 744, 748 (Fed. Cir. 1987); see also Richardson v. Suzuki Motor Co., 868 F.2d 1226, 1236 (Fed. Cir. 

1989) (discussing the doctrine of equivalents as “a legal 

theory that is pertinent to obviousness under Section 103, 

not to anticipation under Section 102”). Notably, however, this court has declined to extend the doctrine of 

equivalents to cover on infringement embodiments that 

were present in the prior art. Wilson Sporting Goods Co. 

v. David Geoffrey & Assocs., 904 F.2d 677, 685 (Fed. Cir. 

1990), overruled in part on other grounds by Cardinal 

Chem. Co. v. Morton Int’l, Inc., 508 U.S. 83, 99–103 

(1993). 
5 SIEMENS MEDICAL v. SAINT GOBAIN

by Judge Dyk (and quoted by the majority) in this court’s 

Festo decision. Maj. Op. at 10 (quoting Festo Corp. v. 

Shoketsu Kinzoku Kogyo Kabushiki Co., 493 F.3d 1368, 

1379–80 (Fed. Cir. 2007)). This appeal now squarely 

presents the issue. 

I believe that the best path through this difficult 

situation is to expressly incorporate Judges Nies and 

Dyk’s reasoning into the equivalence analysis: a separately-patented (and presumptively nonobvious) substitution cannot be “insubstantial” unless some fact 

distinguishes the equivalence finding from the PTO’s 

earlier nonobviousness determination. 

The passage of time presents one opportunity for such 

a distinction. The majority is correct that an equivalence 

analysis differs from an obviousness analysis in the time 

frame concerned. Obviousness is assessed at the time of 

the invention, and equivalence at the time of the alleged 

infringement. A finding that, from the time of the separately-patented invention to the time of accused infringement, the state of the art advanced in such a way as to 

make a previously non-obvious substitution obvious, 

would allow an equivalence finding without upsetting the 

presumption of nonobviousness. In the absence of such a 

finding, in my view a separately-patented substitution 

may not be held equivalent. 

Returning to the present appeal, I believe the trial 

court should have given more direct guidance to the jury 

concerning the effect the ’420 patent’s separate coverage 

of Saint-Gobain’s 10% Y LYSO crystals had on the jury’s 

duty as fact finder. Specifically, I believe it was reversible 

error for the court not to inform the jury that it could find 

equivalence if and only if it also found that the state of 

the art concerning LSO crystals had advanced from the 
SIEMENS MEDICAL v. SAINT GOBAIN 6

time of the ’420 patent’s invention to the alleged infringement so that the 10% Y composition, though previously nonobvious, had become obvious and insubstantial.2 

I therefore respectfully dissent. 

 2 In this appeal, Saint-Gobain sought a jury instruction emphasizing the ’420 patent’s presumption of 

validity. I believe such an instruction should have been 

given, and so dissent. But in my view the additional 

guidance set forth herein was necessary to give full effect 

to the instruction Saint-Gobain articulated.