Patent Infringement Litigation - Module 5 of 5
Module 5: Patent Infringement Litigation
The sole means of enforcing a patent is through litigation. This module focuses on the procedure of patent litigation, various types of patent infringement, defenses to infringement and remedies.
Initiating the Litigation
Federal courts have exclusive subject matter jurisdiction over patent infringement litigation. All patent litigation occurs either in federal district courts or, less frequently, in the International Trade Commission.
In patent litigation in federal district courts, the patent owner - known as the “patentee” - can seek an injunction, basic economic, potentially enhanced damages and attorneys’ fees. The district court chosen for litigation must have personal jurisdiction over the alleged infringer, which requires sufficient minimum contacts with the court’s forum state. Such minimum contacts can be established through a variety of mechanisms, such as the purposeful direction of business activities towards the state or the placement of infringing products in the stream of commerce that reaches the state.
The issue of venue
presents a much more significant hurdle for patentees in choosing the
appropriate forum. Prior to the Supreme
Court’s 2017 TC Heartland decision, a defendant could be sued for
patent infringement in any district court having personal jurisdiction over the
accused infringer. Because patentees
were free to choose the forum, a single pro-patentee district -- the Eastern
District of Texas -- handled more than a third of all patent litigation. In TC
Heartland, the Supreme Court significantly narrowed the venue
options, ruling that patent lawsuits can be brought only where the alleged
infringer resides or has committed acts of infringement and has a
regular and established place of business.
deemed to “reside” only in their states of incorporation. Thus, since this
decision, the District of Delaware has seen an influx of patent litigation
because many companies are incorporated in Delaware. Out of a desire to avoid lawsuits in the
Eastern District of Texas, many corporations closed their regular places of
business in the district, eliminating that district as a potential venue. Judges in the Eastern District have responded
with some overly expansive interpretations of what constitutes a “regular and
established place of business,” once going so far as to rule that Google’s
cache servers in the district, in a space leased from internet service
providers, subjected Google to suit in the district. Nevertheless, patent litigation in the
Eastern District of Texas has fallen drastically.
In most patent
infringement litigation, the local rules or the judge’s own procedures impose
requirements that differentiate patent litigation from other types of
litigation. For example, the patentee
typically must make an early decision regarding which claims are infringed, and
the patentee must provide detailed infringement contentions. These contentions are typically part of a
claim chart, which contains each element of each claim in the left column and
evidence of infringement in the right column. In addition, these contentions must specify
which types of infringement are at issue.
Following service of the infringement contentions, the accused infringer must provide detailed invalidity contentions if it wishes to challenge the validity of the patent. Patents can be invalidated for any of the reasons they could have been denied at initial application, including anticipation by prior art, obviousness based on a combination of prior art references, improper listing of inventors and lack of subject matter eligibility. The accused infringer’s invalidity contentions must specify the grounds for invalidity. For any anticipation or obviousness defenses, the accused infringer can provide a claim chart, showing where each element of each asserted claim is found in the prior art.
Stages of Patent Litigation
Patent litigation often hinges on the words used to describe the inventions in each asserted claim of a patent. The judge overseeing each case must make determinations regarding the meaning of each disputed term. To do so, judges typically request a Markman hearing, in which the parties -- and often their expert witnesses -- educate the judge regarding the technology at issue and explain why certain terms should have a certain meaning. 
Parties typically base their proffered meanings on strategic considerations. For example, where infringement is fairly clear, but where the prior art could cause some validity concerns, patentees might propose narrow definitions, while the accused infringers might proffer broad definitions. The evidence used to support these “claim constructions” must focus on the term in the context of the claim language, the use of the term in the description of the patent, and any discussion about the term in the written history of the patent prosecution. After considering all of this “intrinsic” evidence, the judge may also consider “extrinsic” evidence, such as dictionary definitions, treatises and expert testimony.
A few other
issues are unique to Markman hearings. First, the words of a patent are generally
given their ordinary and customary meaning as understood by a person of
ordinary skill in the art in the context of the specification and prosecution
history. If the patentee wants to depart from this
meaning or simply wants to avoid any controversy during litigation regarding
the meaning of a term, the patentee is allowed to act “as his own
lexicographer” by clearly setting forth the definition of a term in the
patent’s written description.
concept of prosecution history estoppel can limit the range of
definitions that a patentee can provide during litigation. For example, if a patentee argued for a
certain meaning of a term during prosecution of the patent, such as to avoid
some invalidating prior art, the patentee cannot proffer a broader meaning at
the Markman hearing.
patents are subject to claim construction. While the claims of design patents
are the figures themselves, the judge must determine whether any of the design
features are purely functional. If so, these features should be ignored in
any infringement and invalidity analyses.
As in other
litigation, patent infringement lawsuits include discovery periods, which can
be the most time consuming and expensive aspect of the lawsuit. Each party is allowed to serve broad
interrogatories, request broad categories of relevant documents and depose up
to ten witnesses. Patentees typically
depose those people responsible for the development of the allegedly infringing
products, often trying to find evidence of intentional copying of the patented
invention. Patentees can also build
their damages cases with information learned during the discovery phase. Accused infringers often depose the inventors
of the patent, hoping to obtain testimony that would be useful in a Markman hearing, and also hoping to find
evidence of improper inventorship or prior art that was intentionally withheld
during prosecution of the patent.
fact discovery phase, the parties engage in expert discovery, which is essential
for motion practice and trial. In most
patent cases, patentees hire technical experts to provide detailed infringement
reports, and accused infringers hire technical experts to write detailed invalidity
reports. In addition, accused infringers
typically hire damages experts to prepare reports detailing the bases and
amounts of all claimed damages. Finally,
each parties’ technical experts can provide rebuttal reports to the other
sides’ experts. The expert witnesses are then deposed, and their testimony and
reports are used in drafting dispositive motions.
Once discovery is
over, each side can move for summary judgment as with all litigation. Assuming
that the dispositive motions do not end the case, patent litigation proceeds to
trial, for which there is the same right to trial by jury as in other
civil litigation. Patent litigators and expert witnesses must therefore be
uniquely skilled at comprehending the complex technology and presenting it to
lay jurors in an understandable fashion.
This process starts as early as voir dire, and the opening
statements are vital. Graphics and other
demonstratives also play key roles. At
the close of evidence, the parties might move for judgment as a matter of law. If they are unsuccessful, the judge will
instruct the jury and the jury will render its determination of all factual
issues, including those pertaining to infringement, invalidity and damages.
Parties to patent
litigation can appeal the trial verdict to the Federal Circuit Court of
Appeals. It is not uncommon to have
cross-appeals, such as the accused infringer appealing an infringement finding
and the patentee appealing the amount of damages. Appeals often drag on for years, and cases
are often remanded to the district court following appeal and partial or full
reversals. As a consequence, some patent cases involve outdated technology by
the time they are ultimately resolved.
Types of Infringement
The most common type of patent infringement is referred to as literal infringement, which means that every element of an asserted claim is in the accused product. For example, suppose a patent claim covers a vehicle with an internal combustion engine, two doors and four wheels. To literally infringe, an accused product must be a vehicle with an internal combustion engine, two doors and four wheels.
infringement, an accused infringer can also be liable for infringement by
equivalence. If some claim elements
are not literally present in the accused product, the Doctrine of
Equivalents provides that there can still be infringement if the accused
product has an element that is substantially equivalent to the missing
element. For example, if the vehicle
lacked an internal combustion engine, but instead had an electric engine, there
could still be infringement.
Traditionally, the patentee would have to prove that the substitute
element performs the same function in substantially the same way to achieve
substantially the same result.
This “function-way-result” test is still used, although recent cases have applied an “insubstantial differences” test for the Doctrine of Equivalents. This test provides that the entire accused product must be substantially similar to the product described in the patented claim.
One interesting twist regarding the Doctrine of Equivalents is known as “prosecution history estoppel.” If a claim was narrowed during prosecution to avoid the problem of some prior art, the patentee may be “estopped” from asserting the Doctrine of Equivalents, as allowing this broad rule to apply to shifting patent claims could be unfair to other users.
infringement can also be categorized as either direct or indirect. Direct infringement is the most
common, and it occurs when a person or entity makes, uses or sells a patented invention
within the United States, or imports a patented invention into the United
States. Indirect infringement means
inducing someone else’s direct infringement or contributing to direct
infringement occurs when someone knowingly aids and
abets direct infringement by another. This requires knowledge that the induced acts
constitute patent infringement. The inducer must know that the patent existed
or must have been willfully blind to its existence. For example, suppose a Canadian manufacturer
obtains a product marked with a U.S. Patent number, copies that product and
sells it to an American company, knowing that it will be resold in the United
States. Even though the Canadian
manufacturer did not directly infringe the patent in the U.S., it could be
liable for induced infringement if the American company is liable for direct
infringement occurs when a party gives away or sells
a component of a patented combination constituting a material part of the
invention, knowing that the component was made or can be adapted for use in the
infringement of the patent. As with induced infringement, the accused
infringer must have knowledge of the patent.
Contributory infringement does not apply where the component is a staple
article of commerce suitable for non-infringing use. For example, a semiconductor manufacturer
selling Apple-specialized chips for iPhones could be liable for contributory
infringement of a patent claiming a mobile phone with those chips. But the
manufacturer of an AA battery would not be liable for contributory infringement
of a patent claim requiring a battery.
infringers raise the same two defenses in nearly every patent infringement
action -- non-infringement and invalidity. The patentee bears the burden of proving
by a preponderance of the evidence, so the patentee must show that it is more
likely than not that there is an infringement.
Accused infringers, of course, try to establish that it is more likely
than not that there is no infringement.
Patents issued by
the USPTO are presumed valid, and accused infringers bear the burden of proving
invalidity by clear and convincing evidence. The most common invalidity defenses are anticipation,
where a single prior art reference discloses all elements of a claim and obviousness,
where multiple prior art references are combined to cover all elements of the
patent. To establish an obviousness
defense, the accused infringer must prove that, assuming knowledge of the prior
art, the claimed invention would have been obvious to persons having ordinary
skill in the art at the time of the invention.
Patents can also
be invalidated for lack of subject matter eligibility. For example, patent claims covering a law of
nature, mathematical equations or certain methods of organizing human
activities are invalid.
A patent can also
be invalidated if the inventorship listing is improper. Each
listed inventor must have made a significant contribution to the conception of
at least one of the claims of the patent.
In addition, no person who made such a contribution may be omitted.
equitable defenses apply to patent claims.
For example, a patent can be rendered unenforceable if the accused
infringer establishes, by clear and convincing evidence, that the inventor
failed to supply material information to the Patent Office, or supplied false
information, with the intent to deceive the Patent Office. The failure to disclose known, relevant prior
art often forms the basis for an inequitable conduct defense.
estoppel is another defense to patent
infringement. Equitable estoppel occurs
when the patentee communicates something to the infringing party that indicates
no infringement or that the patent will not be enforced, and the infringing
party relies upon the communication. For
example, if a patentee, during negotiations with the alleged infringer, said
that she would refrain from enforcing the patent if the infringer limited the
scope of marketing the new product and the infringer did limit the marketing
scope, the patentee may be estopped from enforcing it. This is true even if
there was no binding contractual agreement on this point.
A patentee who
prevails on a claim for patent infringement is entitled to damages of at
least a reasonable royalty. Damages
experts propose royalty rates based on the factors set forth in the Second
Circuit Georgia Pacific case,
which include past royalty rates for similar patents, the nature and scope of
the license, the commercial success of the product and other factors.
The patent owner
can alternatively seek its lost profits, which are the profits the owner would
have obtained but for the infringement. The infringer can defend against a
claim for lost profits by establishing that there were available non-infringing
substitute products on the market that could have been used to generate the
same profits. In addition, a design patent owner can seek
the profits made by the infringer of any article of manufacture that is covered
by the design patent.
patentee can also seek injunctive relief, prohibiting the infringer from
practicing using the patent in the future.
Operating companies that compete against an infringer can typically
obtain permanent injunctions, whereas non-competitors and non-practicing
entities are generally not entitled to injunctive relief.
A patentee can
obtain enhanced damages if it establishes willful infringement by
proving, by a preponderance of the evidence, that the infringer engaged in
egregious activity beyond typical infringement. The judge has the discretion to enhance
damages up to three times the amount determined by the jury.
exceptional cases, the prevailing party is entitled to recover attorneys’ fees
from the losing party. A case is exceptional if it “stands out from
others with respect to the substantive strength of a party’s litigation position
or the unreasonable manner in which the case was litigated.”
Thank you for
participating in Lawshelf’s video-course in Patent law. We hope that you now
have a firmer background in this important area of intellectual property law. We
hope that you will take advantage of our other offerings in intellectual
property law and in other areas. Please let us know if you have any questions or
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 SEVEN Networks v. Google, 315 F. Supp. 3d 933, 947 (E.D. Tex. 2018).
 Markman v. Westview Instruments, 517 U.S. 370 (1996); https://www.upcounsel.com/markman-hearing
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 35 USC § 285
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