Epos Technologies Ltd v. Pegasus Technologies Ltd.

IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF COLUMBIA

EPOS TECHNOLOGIES et al. *
*
v. * Civil Action WMN-07-416
*
PEGASUS TECHNOLOGIES et al. *
*

* * * * * * * * * * * *

MEMORANDUM

Currently pending before the Court are questions regarding

the construction of certain disputed claim terms in this patent

dispute. The parties have provided the Court with a full

complement of memoranda advancing their respective proposed

constructions for each disputed term, and the Court conducted a

Markman hearing to further explore the parties’ arguments. The

parties also submitted supplemental memoranda regarding patent

indefiniteness. Upon consideration of the applicable law, facts

and arguments, the Court issues the following claim

constructions.

I. BACKGROUND

Both EPOS and Pegasus make digital pens that track the

motion of a pen or marker and convert the movements for display

on a computer.1 In 2007, EPOS sued Pegasus seeking a declaratory

1
Plaintiff is EPOS Technologies, Ltd. Counterclaim Defendants
include EPOS, Dane-Elec S.A., Dane-Elec Memory S.A., and Dane-
Elec Corp. USA. Collectively, the Court will refer to them as
“EPOS.” Defendant is Pegasus Technologies Ltd. Counterclaim
judgment that its products do not infringe on four of Pegasus’

patents. Pegasus then counterclaimed and alleged infringement

of six patents, including the first four at issue in EPOS’

Complaint plus two more.

There are six patents at issue in this case.2 Together, the

patents relate to a system developed to convert handwritten

markings—for example, notes on a dry-erase board—into a digital

image for display, storage or further manipulation. The system

utilizes ultrasonic signals to track and triangulate the

position of the marking device on a writing surface. At a

minimum, the technology requires: (1) at least two ultrasonic

signal receivers (or transmitters) mounted on the edge of a flat

surface (such as a dry-erase board); and (2) an ultrasonic

signal transmitter (or receiver) that attaches to the marker,

pen, or other marking device (such as a dry-erase marker) that

the user manipulates to write or draw. The system triangulates

the position of the marker by calculating the time it takes the

ultrasonic signal sent from the marker’s transmitter to reach

each receiver. These time-of-flight (TOF) measurements are then

converted to distance measurements to determine the location of

Plaintiffs include Pegasus and Luidia, Inc. The Court will
refer to them collectively as “Pegasus.”
2
The patents include U.S. Patent Nos.: 6,724,371 (the ‘371
patent); 6,841,742 (the ‘742 patent); 6,326,565 (the ‘565
patent); 6,392,330 (the ‘330 patent); 6,266,051 (the ‘051
patent); and 6,501,461 (the ‘461 patent).

2
the transmitter relative to the receivers, after which the

system interprets that information and stores or displays it

digitally.

Some patents at issue include inventions for multiple

elements of the system. Thus, four patents relate to movable

transmitters or receivers that attach to or are built into

writing implements like markers and pens. Three involve claims

regarding the composition of the entire digitization system, and

a final patent pertains exclusively to the ultrasonic

transceivers used to track the movable transmitter. All of the

patents also include methods of implementing the inventions.

II. LEGAL STANDARD

In Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005),

the Federal Circuit comprehensively outlined the means by which

a court should construe disputed claim terms in a Markman

hearing. In essence, courts must determine the meaning of

disputed terms as they would be understood by “a person of

ordinary skill in the art” at the time the patent was issued.

Id. at 1313. To do so, courts must first consider the patent’s

intrinsic information, starting with the language of the claims

and using the patent specification, prior art and prosecution

history when necessary. Id. at 1314. If the intrinsic

information is insufficient, the Court may use extrinsic

3
information, including technical dictionaries, treatises and

expert testimony. Id.; see generally id. at 1312-19.

Claim construction begins with an examination of the claim

language, because “the claims of a patent define the invention

to which the patentee is entitled the right to exclude.” Id. at

1312. The words of a claim “are generally given their ordinary

and customary meaning.” Id. Nonetheless, “the specification

necessarily informs the proper construction of the claims,” and

“the prosecution history can often inform the meaning of the

claim language by demonstrating how the inventor understood the

invention.” Id. at 1316-17. “Ultimately, . . . [t]he

construction that stays true to the claim language and most

naturally aligns with the patent’s description of the invention

will be, in the end, the correct construction.” Id. at 1316.

If a disputed term is facially unambiguous, the Court may

decline to impose its own construction. Id. at 1312-13.

Similarly, the Court may also decline to construct a term if the

term is “indefinite” or “insolubly ambiguous,” such that the

term’s meaning is so unclear that no amount of evidence could

lead to a proper definition. Halliburton Energy Servs., Inc. v.

M-I LLC, 514 F.3d 1244, 1249 (Fed. Cir. 2008). Courts, however,

should avoid finding terms indefinite whenever possible because

a patent with an indefinite term in an independent claim is

4
invalid and unenforceable. Id. As the Federal Circuit recently

opined:

Of course, claims are not indefinite merely because
they present a difficult task of claim construction.
Instead, if the meaning of the claim is discernible,
even though the task may be formidable and the
conclusion may be one over which reasonable persons
will disagree, we have held the claim sufficiently
clear to avoid invalidity on indefiniteness grounds.
Proof of indefiniteness requires such an exacting
standard because claim construction often poses a
difficult task over which expert witnesses, trial
courts, and even the judges of this court may
disagree. Nevertheless, this standard is met where an
accused infringer shows by clear and convinced
evidence that a skilled artisan could not discern the
boundaries of the claim based on the claim language,
the specification, and the prosecution history, as
well as her knowledge of the relevant art area.

Id. at 1249-50 (internal citations and alterations omitted.)

III. ALLEGEDLY INDEFINITE TERMS

The parties dispute several terms among and across all six

patents and have offered varying proposed constructions. Among

the disputed terms are three that EPOS claims are indefinite, an

allegation that, if true, would render the patents in which the

terms appear invalid and unenforceable. As these allegations

threaten the validity of entire patents, the Court will address

them first.

1. “Spatial frequency.” ‘330 Patent.

The first claim term that EPOS argues is indefinite appears

in Claims 16 and 17 of the ‘330 patent. The claim term in

dispute is underlined below. The patent claims:

5
 16. A method for providing mechanical protection for
an ultrasound transducer used for given frequency of
ultrasound signals while minimizing interference with
the ultrasound signals, the method comprising
positioning a protective grating adjacent to the
transducer, the grating [h]aving a plurality of
openings spaced at a spatial frequency of less than
about half of the wavelength of the given frequency of
ultrasound in air.3

‘330, 12:27-31.

The words “special frequency” form the basis of EPOS’

objection. EPOS argues, simply speaking, that the claim

language misuses the word “frequency” in “spatial frequency.”

Frequency is a measure of periodicity, or the number of times

something happens in a given time or distance (i.e., “ten cycles

per second” or “five bars per inch”). The claim language,

however, uses frequency in “spatial frequency” to refer to a

length. Consequently, EPOS argues that this is incorrect and

the Court should not rewrite an improperly written patent.

In contrast, Pegasus submits that the meaning of the term

as used in the patent is evident from its context. As such,

Pegasus suggests the Court construe the term as: “S is the

combined widths of an opening and a bar or element in the

grating. Lamda is the wavelength of the frequency of ultrasound

in air. S is less than about half of lamda.” Pegasus then

3
EPOS also challenges nearly identical language used in Claim
17. As the Court’s analysis is identical for both Claim 16 and
Claim 17, the Court will only refer to Claim 16 here.

6
refers the reader to Figure 14 of the ‘330 patent’s

specifications.

EPOS is undeniably correct that the claim, if construed

literally, is incoherent. The claim equates frequency and

length as measures of the same property, but this is impossible

as the two are distinct properties.4 Frequency is inversely

related to length, such that wavelength (lambda) is the quotient

of propagation speed (c) divided by frequency (f). Thus, the

question before the Court is whether the claim term as written

is so insolubly ambiguous that no amount of evidence could lead

a person of ordinary skill in the art to understand what it

meant.

To begin with, the context of the claim itself provides a

measure of evidence. The claim refers to “a protective grating

. . . [with] a plurality of openings spaced at . . . .” This

language indicates that what follows should define the

repetitive structure of the grating’s openings. On the basis of

this language only, the grating’s structure could, in theory, be

4
For example, granting several assumptions and generously
substituting several phrases for the sake of clarity, the claim
term as written could fairly be read as calling for “a plurality
of openings with an openings-per-millimeter measurement of 2
millimeters.” To make this example coherent, a reader would
need to invert “openings-per-millimeter” to “millimeters-per-
opening,” just as reader would need to invert frequency before
comparing it to length. Alternatively, the example would be
coherent if “2 millimeters” were replaced with a value of
frequency.

7
defined either in terms of periodicity or in terms of length.5

The claim proceeds, however, to refer to a specific length;

specifically, it refers to “about half of the wavelength of the

given frequency of ultrasound in air.” Granting that the

language immediately preceding “spatial frequency” does not

demand a definition in terms of either periodicity or length,

this leads to two possibilities. Either the term “spatial

frequency” is correctly used to refer to periodicity and the

reference to wavelength is incorrect, or the reference to

wavelength is correct and the term “spatial frequency” is used

incorrectly.

At this stage, the claims themselves provide no further

elucidation, and the Court must look to the patent

specifications for additional evidence. Here, the patentee’s

intentions become clear. When describing the grating at issue,

the specifications explain:

[T]he present invention provides a protective grating
structure 80 in which a periodic pattern of openings
has a spatial period S of no more than [lambda]/2, and
preferably no more than [lambda]/4, where [lambda] is
the wavelength of the ultrasound working frequency in
air. By using a grating with a grating step S
significantly smaller than existing systems, little or
no directional disruption is caused to the ultrasound
signals. . . . By way of practical example, for a
working frequency of 90 kHz, corresponding to a

5
For example, it would not be entirely incoherent to say the
grating should have “openings spaced at one opening per
millimeter,” which would indicate that, say over the span of
five millimeters, the grating should have five openings.

8
 wavelengt in air of abou 4 mm, a gratin step o 1.9
w th r ut ng of
mm has be
m een found to offe minima disrup
d er al ption to the
transmission and receptio of sig
on gnals.
To minimize attenuat
m tion of t
the signa
al, the
proportio of the grating which i open i prefer
p on e g is is rably
maximized subjec to the mechani
m d, ct e ical requ
uirements for
s
the struc
cture. In the af
I forementi
ioned exa
ample, th
he
open area of the grating is prefe
a erably at least a
t about
70% of th total area wit
he thin each [g]rati
h ing step.
.
Alth
hough sho
own here schemati
ically [i Figure 14]
in e
in the fo
orm of a rectangu
ular grat
ting, gra
ating 80 may
clearly be implem
c b mented in a range of diff
n e ferent fo
orms .
. . . Thhus for a cylindr
rical tra
ansducer, . . .
,
grating is prefer
g i rably imp
plemented as a cy
d ylindrica
al
outer sle
eeve havi
ing openi
ings with periodi spacin S.
h ic ng

‘330, 9:26-49. Figure 14, to which th specif
e he fications refer,
s

appear as fol
rs llows:

On the ba
asis of this expl
t lanation and the preferre
ed

pressed in Figure 14, it is evide
embodiment exp i e ent that the

patentee meant to defi
t ine the grating’s opening in ter
g s gs rms of a

specif
fic lengt
th, S. S is a co
ombined m
measure o the le
of engths of
f

one op
pen slot and one structur
ral compo
onent imm
mediately adjacen
y nt

to the open sl
lot, and it is eq
quivalent to less than on
t s ne-half o
or

9
one-quarter of a specific ultrasound wavelength. Thus, the ‘330

patent unambiguously intends to define the structure of the

grating’s openings in terms of length and not in terms of

periodicity. In turn, it follows that the words “spatial

frequency” must refer to a specific length, notwithstanding the

plain and ordinary meaning of those words. This is the only

logical interpretation of the patent, and a reader of ordinary

skill in the art—or any careful reader, for that matter—would

understand the patent as such.

Nevertheless, EPOS argues that the Court should not

selectively construct “spatial frequency” in a manner

inconsistent with the ordinary definition of “frequency” used

elsewhere in the patent. In fact, Claim 16 itself uses the

ordinary definition of “frequency” twice in the phrases

preceding “spatial frequency.” Thus, EPOS argues the Court

should not impose differing definitions for multiple appearances

of the same word in the same claim.

Although EPOS’ argument appeals to consistency and

symmetry, it fails insofar as it refuses to account for the

differing contexts in which the word appears at various times.

This is not a case in which “frequency” appears each time in the

same context. The word properly refers to a measure of

periodicity the first two times it appears in Claim 16, which is

consistent with the context and the patent’s specifications. It

10
is only the third and final use of the word that, when read out

of context, seems incoherent. As described above, however, a

complete reading of the patent leads to only one possible

interpretation of “spatial frequency,” notwithstanding its

ordinary definition. The Court will not artificially impose an

incoherent construction for the sake of consistency, when doing

so would require it to ignore the unambiguous intent of the

patentee.

Consequently, the Court finds that the phrase “spatial

frequency,” as it appears in Claims 16 and 17, is not

indefinite. Moreover, Pegasus’ proposed construction mirrors

closely the language of the patent specifications and will be

adopted. The new construction for the relevant term is: “S is

the combined widths of an opening and a bar or element in the

grating. Lambda is the wavelength of the frequency of

ultrasound in air. S is less than about half [or one quarter]

of lambda. See Fig. 14 of the Patent.”

2. “Annotation implement,” “operative implement,” and

“drawing implement.” ‘371 Patent.

The next terms that EPOS argues are indefinite, “annotation

implement” and “operative implement,” appear in the ‘371 patent.6

6
EPOS does not argue that “drawing implement” is indefinite, but
it does challenge Pegasus’ position that the term does not
require construction. Because the Court’s analysis of
“annotation implement” and “operative implement” implicates

11
Patent ‘371 involves a pen-like device that contains an

ultrasonic transmitter and an infrared transmitter built inside

the device’s body. One preferred embodiment of the device looks

substantially like an ordinary pen and can be used as such.

The ‘371 patent refers to various types of “implements,”

which are described as replaceable cartridges inserted into the

pen-like device. One end of the cartridge protrudes from the

device to make contact with the writing surface. By analogy, a

refillable ink cartridge in a standard pen would qualify as an

“implement” because the cartridge is inserted into the pen’s

outer housing and the tip of the cartridge, the pen tip, is then

used to write on paper. In this context, the ‘371 patent refers

to several types of “implements,” including a “writing

implement,” ‘371, 2:29, an “operative implement,” ‘371, 23:3, a

“drawing implement,” ‘371, 23:6, and an “annotation implement,”

‘371, 23:7.7 The claims of patent ‘371 specifically refer to the

latter three, and EPOS argues that both “operative implement”

and “annotation implement” are indefinite.

The basis of EPOS’ argument is that those two terms have no

ordinary meaning, and that neither the patent’s claims nor its

“drawing implement,” it will be discussed here. EPOS also
challenges the construction of “drawing implement” as it is used
in two other patents, which are discussed separately below.
7
The patent also refers to an eraser as another type of
“implement.” ‘371, 16:61.

12
specifications provide a definition for “annotation implement.”

It further argues that because “operative implement” is defined

in terms of “annotation implement,” it, too, is indefinite,

especially because the patent provides no guidance as how the

two terms should be distinguished. Finally, EPOS submits that,

while not indefinite, the term “drawing implement” should be

constructed consistent with the manner in which that term is

used in the ‘565 and ‘742 patents.

EPOS does not challenge the definition of “implement.” An

“implement,” as used in the ‘371 patent, refers to the cartridge

structure discussed above. Thus, EPOS’ question concerns the

distinction between the various types of implements, but the

question is answered by the ordinary definitions of the words

used throughout the patent’s claims and specifications to modify

“implement.” For example, “operative implement” is used

throughout the specifications merely to refer to whatever

implement the user has currently installed in the device. See

‘371, 19:6-9. This is consistent with the ordinary meaning of

the word “operative,” which the Oxford English Dictionary

defines as “characterized by operating or working, being in

operation or force.” Oxford English Dictionary (3d ed. 2004).

As for the other terms, the specifications teach that the

“[o]perative implement is selectable among a plurality of

different operative implements, including, but not limited to,

13
drawing implements, e.g., of different colors, eraser implements

and annotation implements.” ‘371, 19:6-9. Similarly, the

patent also notes that the “[o]perative implement . . . can be,

for example, a drawing implement, an annotation implement or an

eraser.” ‘371, 16:59-61. Thus, it is evident that drawing,

annotation, and erasing implements are different types of

operative implements. Moreover, the specifications provide no

reason to depart from the ordinary meaning ascribed to “drawing”

and “annotation.” The patent discusses using a “drawing

implement” to draw, ‘371, 11:17-18, and an “eraser implement” to

erase, ‘371, 13:55-58. It also describes the invention as one

that can be used for “digitizing graphical or textual data drawn

on the face of a presentation board and for digitizing

annotations with relation to a screen, such as a computer

screen.” ‘371, 7:18-21. Thus, the patent unambiguously applies

the ordinary and customary meaning of these words, and the terms

are not indefinite. As such, the Court will decline to

construct the terms “operative implement” and “annotation

implement.” The Court will do the same for “drawing implement,”

because as the plain meaning of the term as it appears in the

‘371 patent is unambiguous, the Court need not look outside the

patent claims for additional guidance.

3. “Given time interval.” ‘742 and ‘565 Patents.

14
 The final term that EPOS argues is indefinite is “given

time interval,” as it appears in the ‘742 and ‘565 patents.

Unlike the patents discussed above, EPOS argues that these

patents do not need to be invalidated if “given time interval”

is constructed to ascribe a more definite and concrete meaning

to the words. Even Pegasus argues that a construction is

appropriate for this term, so neither party argues that the term

should remain as it appears in the patents. Consequently, the

Court will impose a construction to avoid any argument that the

term is indefinite.

The ‘742 and ‘565 patents seek to solve, among other

problems, a deficiency of prior art pen-stroke digitization

systems, in which those systems fail to record short, quick pen

strokes a user makes in rapid succession, such as when a user

attempts to draw a dashed line. When a user begins writing with

a digital pen or marker, the pen tip triggers a switch inside

the pen, and the pen “turns on” and begins transmitting a signal

so the system can locate and track the pen’s movements. This is

called “pen-down” because the pen is placed down on the writing

surface. There is a slight delay between pen-down and the time

the system begins tracking because the system must locate the

pen and process the signals. This delay is called the

“resynchronization delay.” Later, when the user removes the pen

15
from the writing surface (“pen-up”), the pen stops transmitting

a signal, and the system stops tracking the pen.

In earlier systems, the resynchronization delay caused

problems when the user would draw a dotted or dashed line

because the pen stroke was so short the system could not

resynchronize fast enough between each pen-up and pen-down

motion. To address this problem, the instant patents create a

system in which the pen continues to transmit a signal for a few

seconds after pen-up. This way, the pen does not need to

resynchronize between pen strokes, and the system is able to

recognize a dotted line. The patent claims call for the pen to

continue transmitting for a “given period of time.”

The claims teach that the pen should continue to transmit

for “a given period of time,” but they make no reference to the

dashed-line problem. The specifications, however, explain

resynchronization delay issues exclusively within the context of

the dashed-line problem. To that end, the specifications

suggest that the pen continue to transmit for “at least about

half a second, and preferably between about 1 and about 2

seconds” after pen-up. See, e.g., ‘742, 11:41-43. Notably,

neither the specifications nor anything else in the patent make

any reference to the resynchronization delay problem outside the

context of drawing dashed lines or similar quick pen strokes

made in rapid succession.

16
 EPOS submits that “given time interval” should be

constructed as “fixed at less than a few seconds” because the

patents contemplate only the dashed-line problem and, thus, the

deficiency the patents seek to solve would require the pen to

continue transmitting after pen-up for only a short amount of

time. Moreover, EPOS formulates its proposed construction by

tracking the language of the specification, which calls for

continued transmission of “preferably between about 1 and about

2 seconds.”

In contrast, Pegasus argues the disputed term should be

defined without an upper or lower bound because no such

limitations appear in the language of the claims. In support of

its proposed construction, Pegasus submits that the patents seek

to solve the resynchronization delay problem generally, even in

contexts other than the dashed-line problem. It argues that a

user may pause when writing “to think or listen,” and the

invention allows the user to resume writing without a

resynchronization delay. Pegasus Br. at 15. It also argues

that the dashed-line problem presented only one example to which

the invention could be applied. Thus, Pegasus submits that the

term should be constructed as “a specified time interval.”

The specifications explicitly note that the

resynchronization delay is only troublesome when drawing short

dotted or dashed lines, and it is typically not a problem when

17
drawing continuous lines. See ‘742, 11:24-25. Because the

patents define the problem as one arising from quick pen strokes

made in rapid succession with very little pause in between them,

it can be inferred that the problem did not extend to pen

strokes made after much longer periods of time, such as when a

user may pause “to think or listen,” as Pegasus argues. Thus,

while the words of the claims do not limit the time interval,

all evidence suggests there must be some upper-bound to the

interval contemplated by the patentee, and there is no evidence

to support Pegasus’ contention that the patents sought to solve

all resynchronization delay problems. Consequently, a person of

ordinary skill in the art, after reading the entire

specifications, would understand that “given time interval” had

some upper bound to it.

While EPOS’ proposed construction more closely aligns with

the patentee’s manifest intent, it is also somewhat problematic.

The upper bound of EPOS’ proposal—“less than a few seconds”—

comes too close to the two-second preference expressed in the

specifications as one possibility. As such, the Court will

impose a minor, perhaps merely semantic adjustment to EPOS’

proposal and construct the term as “fixed at a few seconds or

less,” which should expand slightly EPOS’ proposal. This

expansion accommodates the need for an upper-bound to the term

18
and the recognition that the specifications are meant only to

inform and not to confine the scope of the patent.

IV. DISPUTED TERMS

The remaining terms in dispute do not raise questions of

indefiniteness and do not threaten the validity of any of the

patents. Though some terms appear in multiple patents, they are

cataloged below in alphabetical order.

4. “Drawing implement.” ‘742 and ‘565 Patents.

Patents ‘565 and ‘742 contemplate a device that attaches to

a conventional marker, pen, or the like, preferably a dry-erase

marker. The device is essentially a sleeve into which a user

inserts a writing utensil. The sleeve contains an ultrasonic

transmitter, among other things, thereby enabling a user to

convert a conventional marker into one that can be tracked by

the pen-stroke digitizing system. Here, “drawing implement”

refers to the writing utensil that the user inserts into the

sleeve. The claims specifically call for “a drawing implement

comprising a body, a back end, and a front end opposite the back

end comprising an operative tip,” ‘742, 14:8-10, and a “drawing

implement comprising a central axis and an operative tip,” ‘565,

6:60-61. Thus, these patents are different from the ‘371

patent. Whereas the ‘371 patent teaches a pen-like device with

a transmitter and ink cartridge contained within the device’s

19
housing, these patents teach a sleeve that a user may retrofit

around a stand-alone writing utensil, such as a pen or marker.

Pegasus argues that “drawing implement,” as defined in the

claims of the ‘565 and ‘742 patents, could be anything from a

“stubby No. 2 pencil to a piece of charcoal.” Pegasus Br. at 6.

As such, Pegasus submits that the term requires no further

construction and should not be narrowed. On the other hand,

EPOS imports language from the specifications and preferred

embodiments that indicate that the patentee designed the device

specifically for use with a dry-erase marker or something

similar. Consequently, EPOS proposes that the Court construct

the term as “a conventional stand-alone pen or marker.”

For this term, neither party has advanced a satisfactory

solution. The plain language of the claims is indeed

exceedingly broad, but neither the claims nor the specifications

support the contention that the patent is so broad as to

contemplate using the device with something like “a piece of

charcoal,” unless of course the charcoal had dimensions similar

to those of a standard, more commonly-used writing utensil. On

the other hand, nothing in the patents suggests that the drawing

implement must be limited to a conventional pen or marker. To

note one obvious example, a pencil would easily satisfy the

claims’ definition of “drawing implement.” Thus, although some

of the preferred embodiments refer specifically to dry-erase

20
markers, a person of ordinary skill in the art could easily

conclude that the device taught by the patents could be used

with a wide array of writing utensils. A better construction

will recognize that a “drawing implement,” as that term is used

here, is a stand-alone writing utensil, in the sense that it is

a writing utensil that can be used as such, or that can be used

in concert with the device; the device need not be retrofitted

to the drawing implement in order for the drawing implement to

draw. To that end, the Court will construct the term as “a

conventional writing utensil that can be used alone or together

with the invention.”

5. “Interference.” ‘330 Patent.

EPOS submits that “interference” requires no construction

because it is widely understood in the art. Pegasus argues that

it should be construed as “obstruction, disruption, distortion,

or directional non-uniformity.” EPOS, however, notes that

neither the claims nor the specifications of the ‘330 patent

address any problem related to the directional uniformity of the

signal. Instead, the patent appears to be concerned only with

possible signal obstructions.

In response, Pegasus proposes replacing the reference to

“directional non-uniformity” with “blind spots.” The term

“blind spot,” however, is ambiguous in this context. Moreover,

to the extent “blind spot” has an ordinary definition, it is

21
unclear how it would capture any type of interference not

already covered by the other terms Pegasus uses in its proposal.

Thus, the Court will adopt a compromise solution and construct

the term as “obstruction, disruption, or distortion.” This

should cure EPOS’ primary objection to Pegasus’ initial

reference to directional non-uniformity while still imbuing the

term with an enhanced degree of nuance sought by Pegasus.

6. “Marking Implement.” ‘461 Patent.

Pegasus argues this claim needs no construction, while EPOS

seeks to construe it as “an implement that has a marker tip (and

not a pen tip).” Unlike the claims in the other patents at

issue, the claims of patent ‘461 refer specifically to a

“marker.” See e.g., ‘461, 10:31-32. Moreover, while the

specifications occasionally reference a “pen” and “pen tip,” the

totality of the specifications makes clear that the patentee was

merely using those terms as synonyms for a dry-erase marker.

See e.g., ‘461, 7:31-37 (“The . . . sleeve . . . has an inner

diameter that is adapted to receive . . . a standard dry-erase

marker. Thus, the herein-disclosed marking implement uses a

marker . . . . The sleeve is tapered to follow the tapered

contour of the pen.”) Consequently, the Court will adopt EPOS’

proposal.

7. “Means for affixing the unitary sensor array.” ‘461

Patent.

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 This disputed term appears in a means-plus-function claim

of the ‘461 patent. A means-plus-function claim employs a

specific, statutorily-provided, short-hand method of drafting a

claim. Specifically, “[a]n element in a claim . . . may be

expressed as a means or step for performing a specified function

without the recital of structure, material, or acts in support

thereof, and such claim shall be construed to cover the

corresponding structure, material, or acts described in the

specification and equivalents thereof.” 35 U.S.C. § 112. In

this claim, the phrase, “means for affixing the unitary sensor

array,” is equivalent to “means or step for performing a

specified function without the recital of structure, material,

or acts in support thereof.” Consequently, the statute requires

that the phrase “means for affixing the unitary sensor array” be

construed “to cover the corresponding structure, material, or

acts described in the specification and equivalents thereof.”

Within that framework, EPOS proposes that this term be

construed merely as a “means-plus-function claim with structure

disclosed in figures 1-5” of the patent. Pegasus, however,

complains that EPOS’ suggestion is too narrow because it

excludes Figure 7 of the patent, as well as the equivalents and

associated claim language of the structures referenced in

Figures 1-5. Instead, Pegasus proposes “structures for

23
repeatedly and removably affixing the unitary sensor array

disclosed in the ‘461 Patent and equivalents thereof.”

The parties agree that this means-plus-function claim

invokes Figures 1 through 5 of the patent, each of which

describes a specific structure used to attach a sensor array to

a substantially planar surface like a whiteboard (i.e., double

sided-tape, various hooks, etc.). The parties disagree,

however, on whether the claim language also invokes Figure 7 of

the patent. Pegasus believes that Figure 7 represents a

“structure, material, or act[] described in the specification”

as a “means for affixing the unitary sensor array,” whereas EPOS

believes it does not.

Unlike Figures 1-5, which describe specific structures,

Figure 7 describes possible locations on the white board (or

other substantially planar surface) where a user may attach the

array (i.e., along the top, along the side, and along the

bottom). As such, Figure 7 does not describe a specific

“structure, material, or act” used to attach the array.

Demonstrating that a user may attach the array to the bottom of

a vertical planar surface does not explain how the user could do

so or what type of structure the user could use for that

purpose. Consequently, the claim term does not invoke Figure 7

of the patent.

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 Pegasus also complains that EPOS’ proposal ignores the

associated language and “equivalents” of the structures

presented in Figures 1-5. By statute, however, a means-plus-

function claim necessarily includes the equivalents of the

structures described in a patent’s applicable specifications.

See 35 U.S.C. § 112. As such, EPOS’ proposed construction is

technically correct and complete, but it also does little to

clarify the meaning of the claim in terms a layperson could

easily understand. The Court will adopt EPOS’ suggestion at

this stage, but it reserves the right to revisit the issue if

necessary before this case is tried before a jury. Accordingly,

this term will be constructed as a “means-plus-function claim

with structures disclosed in Figures 1-5.”

8. “Microswitch.” ‘371, ‘565 and ‘742 Patents.

All three patents in which the term “microswitch” appears

involve writing devices that contain ultrasonic transmitters.

The transmitters begin transmitting when the marking tip is

depressed against a writing surface (described above as pen-

down), and they stop transmitting when the marking tip is lifted

(pen-up). The patents refer to the mechanism that detects

whether the marking tip is depressed as a “microswitch.”

EPOS argues that “microswitch” has a very specific meaning

to those skilled in the art. To that end, EPOS submitted the

declaration of Dr. Amit Lal, an expert in the fields of

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ultrasonics and small electromechanical devices. EPOS Br. at

12-13.8 Dr. Lal avers that a microswitch can be only one of two

different types of switches, neither of which looks or works

anything like the structure referred to as a microswitch in

these patents. In turn, EPOS argues that since the patentee did

not mean to refer to either of the two very specific meanings

discussed by Dr. Lal, the patentee must have been acting as his

own lexicographer, in which case the patentee made up his own

definition of “microswitch.” When a patentee acts as his own

lexicographer, the definitions of the terms he creates are

confined to however the terms are defined in the patent’s

specifications. With one exception, the specifications of the

instant patents refer only to a preferred embodiment wherein the

“microswitch” includes the use of a spring. Consequently, EPOS

argues the term should be construed as “a small switch that

utilizes a spring.” Pegasus, on the other hand, submits that

the term should essentially mean a “switch” that is “micro” in

size, which leads them to “a very small switch that is sensitive

to minute motions.”

The claims of these patents do not require the microswitch

to have a spring. Rather, only the preferred embodiments

expressed in the patent specifications refer to a spring. The

8
EPOS’ opening claim construction brief will be cited as “EPOS
Br.” Pegasus’ opening brief will be cited as “Pegasus Br.,” and
Pegasus’ reply brief will be cited as “Reply.”

26
scope of a patent is defined by the claims, not by the preferred

embodiments. Even if the Court accepts that the patentee was

acting as his own lexicographer, the definition of the term need

not include reference to a spring because the specifications do

not preclude embodiments that do not include a spring. For

example, patent ‘742 explicitly refers to a piezoelectric switch

that would perform the same function as a spring. ‘742, 10:3-4.

Thus, the microswitch with a spring, as it appears in

specifications of all three patents, is merely a preferred

embodiment. The language of the claims does not require that

the microswitch use a spring, so EPOS’ proposal is too narrow.

Consequently, the Court will construct the term consistent with

Pegasus’ suggestion as “a very small switch that is sensitive to

minute motions.”

9. “Presentation Board” and “Board.” ‘371 and ‘742

Patents.

The dispute regarding the next claim terms, “presentation

board” or “board,” involves a question about the type and size

of surface for which the patentee created the digitization

system. As discussed above, many preferred embodiments

contained within the patents at issue contemplate a system to be

used with a large board, such as a whiteboard. To that end,

some of the inventions enable the use of tracking systems with

ever larger boards by, for example, providing a method of

27
calculating the location of a marker based on data from several

receivers installed over a wide board. Previously, tracking

systems for use with several receivers spaced over an

exceedingly large board were unavailable. Nevertheless, the

patent claims make no reference to whiteboards or any other

specific writing surface. In addition, some patent

specifications contemplate applications of the technology to not

only whiteboards, but also to writing surfaces “of all sizes.”

‘371, 2:41. Critically, the patent claims refer only to a

“presentation board” or “board.”

In light of the specifications’ heavy emphasis on

whiteboard systems, EPOS submits that the terms are overbroad

and that they should be constructed to more closely mirror the

patents’ preferred embodiments. It also argues that

“presentation board” is inherently a board used for a

presentation, and that a presentation necessarily requires at

least one presenter and an audience. Last, EPOS contends that

“board” is merely shorthand for “presentation board,” so the

Court should impose the same construction for both terms.

Hence, EPOS proposes that both terms be constructed as “a board

designed for presenting information to multiple people.”

Pegasus refutes EPOS’ position and makes the straightforward

argument that the claim language is unambiguous and does not

28
include any limitations. As such, Pegasus maintains that the

term requires no construction.

Based upon the language of the claims, EPOS’ definition is

too narrow. For one example, a presentation may have an

audience of only one, so it is improper to suggest the board

must be used to present information to “multiple people.” In

addition, a statement of intended use—such as the phrase,

“designed for presenting information to multiple people”—in

claim language is not typically a limitation. This is an

instance where, notwithstanding the fact that many of the

patents’ preferred embodiments repeatedly demonstrate a tracking

system for use with a large presentation board, the plain and

ordinary language of the claims is unambiguous and does not

import any limitation on the size of the board to be used.

Since the specifications do not limit the scope of an

unambiguous claim term, the Court will reject EPOS’ proposal.

On the other hand, EPOS is correct in its assertion that

“board” in these claims is merely shorthand for “presentation

board.” This is evident from both the claims and the

specifications. To avoid confusion, the Court will construct

“board” as “presentation board,” but it will otherwise decline

to impose a more narrow construction on “presentation board.”

10. “Retrofittable Apparatus.” ‘051 and ‘461 Patents.

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 The next disputed claim term, “retrofittable apparatus,”

appears in the context of the ‘051 and ‘461 patents, which

describe generally a sensor array that can be attached to or

otherwise used with a pre-existing writing surface. EPOS

objects to this term because it is unclear insofar as it may

refer either to an apparatus that retrofits something else, or

to an apparatus that can be retrofitted by something else. In

turn, EPOS proposes “an apparatus that modifies an existing

piece of equipment,” while Pegasus submits that the term

requires no construction.

EPOS’ definition improperly limits and further confuses the

term with the phrase, “an existing piece of equipment.” The

claims do not require that the invention be used with an

existing piece of equipment and, moreover, the term “equipment”

is ambiguous in this context. Nevertheless, the term as it

appears in the patents is also ambiguous as explained above, so

the Court will construct it as “an apparatus for retrofitting

something.” This construction will clarify that the term refers

to a device that can retrofit something—as opposed to a device

that can be retrofitted by something else—while not importing

any additional limitations not found in the claim terms.

11. “Screen.” ‘371 Patent.

The claims of patent ‘371 often refer to a device to be

used with a “board or screen.” The specifications state that

30
“the present invention can be used for digitizing graphical or

textual data drawn on the face of a presentation board and for

digitizing annotations with relation to a screen, such as a

computer screen.” ‘371, 7:20-21 (emphasis added). Pegasus

argues the meaning of “screen” is self-evident and need not be

further construed. It also argues that the words “such as” are

synonymous with “for example,” and therefore the specification’s

reference to a computer screen is meant only to inform and not

to limit the term. EPOS says the term “screen” is “essentially

meaningless” without reference to the specification. EPOS Br.

at 21. It also submits that “screen” cannot mean the same thing

as “board,” since words in a claim should be interpreted to give

each term meaning and to avoid redundancy. Since the only

reference to a screen in the specifications identifies a

computer screen, EPOS argues the term must be constructed

narrowly as “a video or computer screen.”

The claims do not limit “screen” to a video or computer

screen. For example, Pegasus avers that “screen,” as used in

the claims, could also include a rigid screen in front of a

projection. Moreover, Pegasus argues that the use of “screen”

is not inconsistent with two of the dictionary definitions for

“screen”: “a flat surface on which a picture or series of

pictures is projected or reflected,” and “a surface on which the

image appears in an electronic display.” Both are plausible but

31
the former comports more closely with the term’s definition as

it is used in the claims. To avoid confusion between the

possibly redundant terms “board” and “screen,” the Court will

construct “screen” as “a flat surface on which a picture or

series of pictures is projected or reflected.”

12. “Substantially planar surface” and “writing surface.”

‘051 and ‘461 Patents.

Here, again, EPOS argues the Court should import a

description of the invention from the specifications to limit

otherwise unconstrained claim terms. To align the terms with

the specifications, EPOS proposes constructing them as “a fixed

surface (such as a mounted whiteboard or table).” The

specifications, however, refer only to a preferred embodiment

and do not limit the scope of the invention. The terms as they

appear in the claims are unambiguous, and the Court will decline

to impose a more narrow construction.

13. “Transparent ultrasonic receiver and transmitter

device.” ‘371 Patent.

As discussed above, the ‘371 patent teaches a tracking

system for use with a pen-like writing device. Because the

tracking system operates by calculating TOF measurements between

the ultrasound transmitter located on the writing device and the

ultrasound receivers mounted on the writing surface, the system

technically tracks the location of the writing device’s

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ultrasonic transmitter, and not necessarily the writing device’s

writing tip. For example, if the transmitter is located at the

top of the pen, the system would track the movement of the top

of the pen instead of the pen’s writing tip. To increase the

system’s accuracy, the patentee devised a pen that included a

transmitter that completely surrounded the pen’s writing tip.

The transmitter, however, obscured the pen tip from the user’s

view and made the device difficult to use. To solve this

problem, the patent calls for a “transparent ultrasonic

transmitter or receiver device” near the pen tip. By making the

pen-tip transmitter transparent, the tracking system retains its

accuracy while allowing the user to see the tip of the pen. The

dispute here involves the meaning of “transparent.”

Pegasus argues that the patent details a transmitter device

that is “essentially transparent to both ultrasound and light.”

Pegaus Br. at 11. In that sense, the device would need to

“convey” ultrasonic signals because such signals would need to

pass through the device in order to be transmitted or received.

Thus, Pegasus advocates a construction of “a device that is

designed to (i) convey light without appreciable scattering and

(ii) transmit, receive, or convey ultrasonic signal(s).” In the

alternative, Pegasus agreed in its Reply that it would accept

the term as it appears in the claim.

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 EPOS, however, takes specific issue with “or convey” in

Pegasus’ construction. It argues that the term is vague and

would capture almost any device that allows ultrasonic signals

to pass through it, including an otherwise opaque device. This

may include, for example, a device with an ultrasonic

transmitter located apart from the transparent pen tip within an

opaque portion of the pen’s housing. Instead, EPOS suggests “an

ultrasonic receiver or transmitter made from transparent

ultrasonic polymer,” because the specifications explicitly note

that transparent piezoelectric polymers are known in the art.

In light of the claims and specifications, Pegasus’

proposed language appears overbroad. As EPOS argues, the words

“or convey” are unnecessary and expand the scope of the claim.

Yet, EPOS’ construction is also insufficient. The claim

language calls for a transmitter device that is transparent, but

it does not specify that the device must be made of a

“transparent ultrasonic polymer.” Although the specifications

note that transparent polymers are a known means of creating

transparent transmitters, neither the claims nor the

specifications require that the transmitters be made of such

polymers. Moreover, counsel at the Markman hearing averred that

a person of ordinary skill in the art would be aware of a design

for a transparent ultrasonic transmitter that did not require

the use of transparent piezoelectric polymers. Thus, for this

34
term, the Court finds that the plain and ordinary meaning of the

claim language is unambiguous and of sufficient clarity, so the

Court will not construct it further.

14. “Ultrasound receiver assembly” and “receiver

assembly.” ‘742 Patent.

The final disputed terms appear in the ‘742 patent. They

are “ultrasound receiver assembly” and “receiver assembly.”

Patent ‘742 contemplates primarily an ultrasound transmitter

device for use with a stand-alone writing utensil similar to a

dry-erase marker. Separately, however, the patent also

describes a preferred design for an “ultrasound receiver

assembly” consisting of two receivers stacked on top of each

other to increase the assembly’s accuracy. The definition of

this assembly is in dispute.

EPOS suggests that the terms be defined as “two ultrasound

receivers connected so as to generate a total output signal

corresponding to the instantaneous sum of the ultrasound signals

received at each of the first and second ultrasound receivers.”

This is exactly the language used in the specification to

describe the preferred embodiment for a more accurate receiver

assembly. Thus, EPOS argues the claim terms refer specifically

to that two-receiver assembly. On the other hand, Pegasus

argues the plain and ordinary meaning of the terms is

unambiguous. Pegasus also argues that the two-receiver assembly

35
described by EPOS is a very common design for a receiver

assembly, which is also “one of the simplest if not the simplest

available receiver assembl[y].” Pegasus Br. at 20. Given the

design’s simplicity, Pegasus argues the patentee “could not have

reasonably intended to limit the scope of [its] invention” to

something so basic. Pegasus Br. at 20.

Here, too, EPOS’ construction is too narrow, because

nothing in the claim requires the use of the preferred two-

receiver assembly. Rather, the specifications discuss “a

preferred design,” which “may be used” with the invention.

‘742, 7:9-13. The specification discloses a preferred

embodiment, but the embodiment does not limit the scope of the

claim. Thus, the Court will decline to construct the term

beyond its plain and ordinary meaning.

V. CONCLUSION

For the foregoing reasons, the Court will construct the

disputed terms as set forth above. The Court will issue a

separate order to that end.

/s/
William M. Nickerson
Senior United States District Judge

August 9, 2011.

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