Searching over 5,500,000 cases.

Buy This Entire Record For $7.95

Download the entire decision to receive the complete text, official citation,
docket number, dissents and concurrences, and footnotes for this case.

Learn more about what you receive with purchase of this case.

Epos Technologies et al. v. Pegasus Technologies et al.

August 9, 2011


The opinion of the court was delivered by: William M. Nickerson Senior United States District Judge


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.


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.*fn1 In 2007, EPOS sued Pegasus seeking a declaratory 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.*fn2 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 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.


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 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 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.)


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: 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.*fn3

'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 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.*fn4 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 defined either in terms of periodicity or in terms of length.*fn5

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 wavelengtth in airr of abouut 4 mm, a gratinng step oof 1.9 mm has beeen foundd to offeer minimaal disrupption to the transmission and receptioon of siggnals.

To mminimize attenuattion of tthe signaal, the proportioon of thee gratingg which iis open iis preferrably maximizedd, subjecct to thee mechaniical requuirementss for the struccture. IIn the afforementiioned exaample, thhe open areaa of the grating is prefeerably att least aabout 70% of thhe total area witthin eachh [g]ratiing step..

Althhough shoown here schematiically [iin Figuree 14] in the foorm of a rectanguular gratting, graating 80 may clearly bbe implemmented inn a rangee of diffferent foorms . . . . Thhus for aa cylindrrical traansducer,, . . . grating iis preferrably impplementedd as a cyylindricaal outer sleeeve haviing openiings withh periodiic spacinng S. '330, 9:26-49. Figuree 14, to which thhe specifficationss refer, appearrs as folllows:

On the baasis of tthis expllanation and the preferreed embodiment exppressed iin Figuree 14, it is evideent that the patentee meantt to defiine the ggrating'ss openinggs in terrms of a speciffic lengtth, S. SS is a coombined mmeasure oof the leengths off one oppen slot and one structurral compoonent immmediatelyy adjacennt to the open sllot, and it is eqquivalentt to lesss than onne-half oor 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 ...

Buy This Entire Record For $7.95

Download the entire decision to receive the complete text, official citation,
docket number, dissents and concurrences, and footnotes for this case.

Learn more about what you receive with purchase of this case.