This article is written by Diksha Paliwal. It discusses in detail the laws pertaining to patent infringement in the US with the help of relevant US case laws. It also provides a basic understanding of the term patent and its origins in the US. 

It has been published by Rachit Garg.


As an inventor, you’ve probably heard of patent infringement, but do you know what it is and how it affects you? Patent infringement is a serious issue that affects inventors, businesses, and the public. The article begins with an introduction to the meaning of the term “patent,” followed by a short discussion about the origin of the US Patent System and law and the need for patent infringement laws looking into the present scenario of rising global trade. It then discusses different types of patent infringement in the US, along with various US case laws and important judicial pronouncements in the field of patent infringement. 

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Innovations deserve to be protected to retain the exclusivity of something to which the innovator has applied his time, efforts, and intellect. The first right of enjoyment and indispensable advantage must lie with the innovator, and at this very thought, the term ‘patent’ comes into the picture. These inventions of intellect come under the purview of intellectual property and, thus, can be protected by getting a patent for such an innovation or invention. When looked at from a broader perspective, the objective of patents is to protect the interests of the innovator and promote the progress of science and technology, art, and various other new inventions in diverse fields. With the increasing thirst for unending learning and gaining information, new ideas of growth and innovation flow, thus increasing the importance of the protection of these intellectual properties. 

Patent under US law

A patent is a kind of incorporeal property, i.e., jura in re propria (ownership of the intangible property). In layman’s language, a patent refers to an exclusive right that is granted to the innovator for his or her invention. The invention (Section 35 U.S.C. 100(a)) made by the innovator may be a product or a process that facilitates or lays out a new method of doing something. It comes under the purview of intellectual property and is related to or deals with inventions. It is a right that an inventor is bestowed with for the invention of various material or immaterial things like machines, art pieces, designs, techniques, etc. However, for the grant of patent rights, it is crucial that the invention be entirely new and not even slightly based on something that already exists. It must be non-obvious. The patent under US law is issued by the United States Patent and Trademark Office

As soon as a person receives a patent, he gets an exclusive right over that invention, and no other person without prior permission from the patent holder can make, import, or sell the patented invention. It is to be noted that a right that a person gets after the issuance of a patent for his or her discovery is negative in nature and not a positive privilege. It endows the patentee with a right to prevent the manufacture, sale, importation, etc. of his or her invention. 

Patents in the US are governed by the Patent Act (35 U.S. Code). This separate Act was enacted by Congress as per the powers conferred on it under Article I, Section 8, Clause 8 of the US Constitution. Congress is empowered to secure the interests of inventors by granting them exclusive rights to their discoveries for a limited period. The department that grants patents, i.e., the United States Patent and Trademark Office, was established under this Code. 

Contents of a patent

Clause (1) of Section 154(a) mentions that a patent is to contain a short title of the invention and a grant of the exclusive right to the patentee, his nominee, or heirs to protect the making, selling, or importing of his invention by a third person. Also, as per Clause (4) of Section 154, a patent must be annexed with the specification and drawing of the invention. 

Term of patent

35 U.S.C. 154(a)(2) talks about the term of the patent granted. It states that a patent is valid for twenty years. The period starts from the date on which the patent was issued and ends after 20 years from the date on which the patent application was filed in the United States. Apart from this, if the application for patent filed is in specific reference to an application that has been filed before this new application, or under Sections 120, 121, 365(c), or 386(c), then the term will be counted from the date of the earliest application. 

Types of patents 

As per the Patent Act (35 U.S. Code), the United States Patent and Trademark Office issued three different types of patents, namely, utility patents, design patents, and plant patents. Let’s have a brief overview of these three kinds of patents. 

Utility patent

Out of the three categories of patents, utility patents are the most common and preferred of all. It is also called “patents for invention.” It is a type of patent that covers how a product works or functions. The invention must be  non-obvious and useful. Software, computer machines, different strategies, tools, equipment, chemical treatments, improvements, etc. fall under the category of utility patents. For instance, a new method of putting on fake lashes can be patented under this category. After fulfilling the condition of paying the patent fees, the owner of the patent secures an exclusive right over the patented invention for 20 years, which begins from the date of filing of the said application. This category of patents covers a broad and much safer protection than the others. However, the hefty maintenance fees and the lengthy procedure and time make the issuance of this patent a cumbersome process.

It is important to note that to get a utility patent for an invention, the product or procedure must be useful, i.e., it must be of some utility. 

Design patent

Broadly speaking, this kind of patent covers how a product appears or looks. The look of the product has nothing to do with the usefulness of the procedure or the task for which it is made. A design patent is issued in reference to a new and authentic design or look that is contained within or applied to a product that is being manufactured. The provisions for design patents are enumerated under Chapter 16 of the 35 U.S.C.

As per Section 173 of the US Patents Act, the term of a design patent is 15 years, unlike that of a utility patent, which is twenty years. The term begins on the date of issuance of such a patent. Even though these are the most easily obtained patents, they are also the ones that are least sought. These patents are granted for the design or look of the patent. For instance, if a person has specifically invented a hair dryer that looks somewhat oval and has a particular design, he can seek a design patent for his hair dryer.  

Plant patent

These kinds of patents are the least popular ones and are granted in favour of an asexually reproducible plant. The provisions for plant patents are enumerated under Chapter 15 of the 35 U.S.C. These plant patents are covered under the purview of Section 161 of the 35 U.S. Code. If a person has discovered a new species of plant, he can get a plant patent for it to stop other companies or individuals from breeding that particular species. It is important to note that no maintenance fees are required to maintain a plant patent in force.

Patent infringement in the US : a general overview

A patent is considered personal property under US law. Any kind of violation of that property comes under the purview of infringement. The owner of the patent, in the event of an infringement of his property rights, has a civil remedy and, thus, can sue the person for such an infringement. Put simply, the term ‘patent infringement’ connotes unauthorized and illegal manufacturing, importing, selling, etc. of the patented invention. It is a violation of the exclusive rights of the patentee that he gets once he or she has patented a particular product or procedure. Patent infringement is considered a strict liability offense. It is a violation of the rights of a patent owner for a particular invention. A person is guilty of patent infringement if he or she, without the permission of the patentee, makes, uses, or imports the invention, provided it is done within the prescribed term period as provided under 35 U.S.C. Chapters 28 and 29 of the 35 U.S.C. deal with various provisions pertaining to patent infringements, their remedies, etc. 

As per Section 271(b) of the 35 U.S.C., a person who is actively involved in or induces infringement of a patent is termed an “infringer”, and a person who sells a product deliberately, even after knowing that the product is made or adapted by infringement of a patent, is called a “contributory infringer” (Section 271(c) of the 35 U.S.C.). Any individual who offers to sell, manufacture, or import a good that he knows is a patented product or invention will be held to be a contributory infringer. Even indulging in or facilitating such an act falls under the purview of infringement. 

It is important that the infringer have knowledge or notice of the patent, otherwise, the patentee cannot claim damages for infringement. Notice or knowledge pertaining to a patent can be brought upon either by way of marking the product or by sending a cease and desist letter to the infringer. It can also be done by filing an infringement action. Furnishing an actual notice to the infringer is essential to further proceeding against the accused for patent infringement. Generally, the awarded cost of patent infringement must not be less than a reasonable royalty combined with interest and cost as directed by the court.

In most cases, if the patent owner satisfies the court by proving the losses that he has suffered, then the amount fixed as monetary compensation is mostly the damages that he has suffered from the losses. However, if the losses cannot be measured or calculated, then a reasonable royalty is directed to be given to the patent owner as damages. The court can also award punitive damages to the patent owner and can even award damages three times the amount of actual damages suffered in cases of wilful or direct infringement.  

Section 271: a brief overview of infringement of patents

Section 271 of the 35 U.S. Code deals with the provisions pertaining to the infringement of patents. It deals with the scope and extent of the protection granted to the patentee and various conditions that will amount to infringement. 

The extent to which the patented invention can be used in whatever manner is always specifically mentioned in the granted patent claims. It expressly clarifies the scope and extent of protection granted to the patented invention. It is important to understand that patents are territorial in nature, and thus a person will be held guilty or liable for the offense of infringement if the violation is committed within the boundaries of the United States (35 U.S.C. 271(a)). 

As stated above, clauses (b) and (c) of Section 271 provide for the meaning of the terms “infringer” and “contributory infringer.”

Clause (d) of Section 271 of the U.S.C. lays down certain conditions that will be deemed to be infringement and other protections that the patentee has over his or her patented invention. Thus, no patent owner shall be held guilty of infringement or will be denied relief in the following situations;

  • If a patentee owner derives revenue from his invention, he shall not be deemed guilty of any patent infringement. However, the same will amount to infringement if performed by another without the patentee’s consent.
  • If the patentee licenses or authorizes another to perform acts in reference to the invention, it will not amount to infringement, but if the same is done without the consent of the patentee, it will amount to infringement.
  • If he chooses to enforce his patent rights against the infringer or the contributory infringer, he shall not be denied such a remedy if the claim seems genuine.
  • If any of the patent rights are licensed on certain conditions or the sale of the patented product in the event of the acquisition of a license in another patent. 

Clause (e) of the Section provides that using, selling, or importing a patented product in the US will not amount to patent infringement if the same is done only for the purpose or in relation to the development and submission of data or information under the law pertaining to the manufacture, use, or sale of drugs or veterinary biological products.

Clause (2) of the Section states that submission of an application for a patent under Section 505(j) of the Federal Food, Drug, and Cosmetic Act or described in Section 505(b)(2) of such Act, and an application under Section 512 of such Act or under the Act of March 4, 1913 (21 U.S.C. 151 – 158), will amount to patent infringement. 

Clause (4) provides for certain remedies that a Federal Court grants for any such acts as mentioned in Clause (2) of the Section. A patentee can be granted injunctive relief against the infringer until the suit attains finality. Also, monetary damages can be awarded to the patentee by the infringer, but only if there has been any selling, or manufacturing of any drugs, veterinary biological products, or biological products. 


Once the court has found a person or company guilty of patent infringement, the infringer must pay the damages to the patent owner in the form of actual damages or a reasonable royalty. The term actual damages includes the lost profits that the patent holder has suffered while the term reasonable royalty depends upon various facts like the type of product, the left term of the patent, other royalty arrangements, etc. Along with the damages, the party is also entitled to costs, which include attorney’s fees, court filing fees, and all the other litigation expenses. The infringer is also restrained from further use, manufacture, sale, and importation of the infringing product. Put simply, the court orders a permanent injunction, once the accused is found guilty of a violation of the patent.

In certain cases, the patent holder can seek a temporary injunction at the initial level, especially when the chances are that it may take a long time to decide the lawsuit, and until then, if it is in the interest of justice and if such an injunction will cause no detriment to the public interest.

Types of patent infringement in the US

Patent infringement is the unauthorized use of an invention that is protected by a patent. It is a violation of the exclusive rights a patentee possesses over his patented invention. It is the right that allows the patent owner to exclude others from interfering with, using, selling, or importing his patent product. There are two types of patent infringement in the US: direct infringement and indirect infringement. In order to sue a person or company under these kinds of patents, it is crucial for the patent holder to show that a part of his patented product or an entire part of the patented claim is present in the accused These different kinds of patent infringement claims arise when a person or a company uses, manufactures, sells, or imports a patent product or its parts of any kind. 

Direct infringement

Direct infringement occurs when someone uses or makes a patented invention without the patent holder’s approval. The infringer does so without having or obtaining any license in pursuance of the patented invention. It is important that infringement be a wilful act and be done in the United States. This type of infringement is often referred to as literal infringement or wilful infringement. In literal infringement, the infringer literally uses the invention as described in the patent. Wilful infringement is when someone knowingly and deliberately infringes on a patent.

Under direct patent infringement, the infringer’s product is exactly similar to the original product, and its process, function, and outcome are entirely the same as those of the original product. Direct infringement is simply copying every element of the original patented product or invention. In cases of direct infringement, it becomes easy for the plaintiff to prove the guilt of the defendant since the onus of proof in such cases lies on the plaintiff. The courts in cases of direct infringement usually award much more damages than in  other classifications of infringement.

In the case of Warner Jenkinson Co. v. Hilton Davis Chem (1997), both parties, i.e., the plaintiff and defendant, manufactured methods of purifying dyes. In this case, the main issue before the court was whether the petitioner infringed any patent claims of the respondent  under the doctrine of equivalents. In the case, Hilton Davis sued Warner Jenkinson, thereby claiming a new method of purifying dye. The process of both the manufacture and purification of the dye was similar, except for the part about the pH scale. For this reason, it was clear that Warner’s process did not literally or directly infringe Hilton’s invention, and hence a plea under the doctrine of equivalence was made. The Supreme Court reversed the judgment of the Court of Appeals and stated that the doctrine is to be applied on an element-to-element basis and hence that the petitioner did not infringe the respondent’s patent claim. Apart from this, it was established in this case that direct patent infringement is a strict liability offense, even though the U.S.C. does not expressly mention the same. 

Indirect infringement

Indirect infringement occurs when someone aids, abets, or encourages another person to infringe on a patent. Put simply, it includes an infringement activity done by way of actively inducing such an act or something done by a contributory infringer. This type of infringement is often referred to as ‘contributory infringement’. Contributory infringement occurs when someone aids in making, selling, or offering a sale of a product that is used in an infringing manner. Since in indirect infringement, the elements of the patented product are the same only up to some extent, it becomes difficult for the plaintiff to prove the offense of indirect infringement. 

Indirect infringement occurs when the infringer partly tries to copy the patented product. It also amounts to indirect infringement when a party induces a third party to indulge in the offense of indirect infringement. Under US law, indirect infringement is classified under two heads, namely, contributory infringement and inducement infringement. A person or a company can be held liable for contributory infringement if the infringer sells a product that particularly does not have any substantial non-infringing use, even though the product’s elements are not entirely similar to those of the original product. A party may be held liable for infringement by inducement if it actively induces a third party in any manner that will result in the act of a third party directly infringing the patent holder’s right. In cases where it becomes difficult to establish guilt in direct infringement, especially when an infringement claim is against the parties that work in a supply chain, recourse by way of infringement by inducement is a much more suitable option for getting back the damages.

In the case of Warsaw Orthopedic, Inc. v. NuVasive, Inc. (2015), the Supreme Court of the United States held that to establish the guilt of induced infringement, the patentee must show to the court that the defendant had knowledge of the patent and also knew the fact that the alleged act was infringing. The Court stated that if the plaintiff satisfies the court that the defendant’s belief that the acts done by him are non-infringing is completely unreasonable. 

Doctrines related to patent infringement

There are broadly two doctrines related to patent infringement in the US: the Doctrine of Equivalents and the Doctrine of Colorable Variation.

Doctrine of Equivalents

The Doctrine of Equivalents states that someone can infringe a patent even if they do not literally use the invention as described in the patent. When the party does not directly or literally infringe the patented product, recourse to get damages from the infringer can be sought under the doctrine of equivalents. This doctrine is used to protect a patent holder from someone who makes minor changes to an invention that are not enough to make it a new invention.

In simple language, the doctrine of equivalence refers to a situation when something that is created works or functions in exactly the same way as that of an existing patented product and gives the same outcome or result. Such a doctrine is mostly relevant when the newly invented product is somewhat better than the original patented product; however, the working style and outcome are the same.

To determine whether the aforesaid doctrine is applicable or not, the court must inquire whether the role played by each element of the patented claim is equivalent or matches the function, way, and, result of the original product, or whether the role played by the infringed product is substantially different from that of the original product. In the case of Warner Jenkinson Co., Inc. v. Hilton Davis Chemical Co. (1997), the Supreme Court of the U.S. held that the doctrine of equivalents must be applied on an element-to-element basis. The Court further stated that to apply this doctrine, the court cannot apply the rule to the whole invention; rather, it must be applied on an element-to-element basis. To determine whether the substituted element is the equivalent of the element in the original product, analyzing the role of each element and then comparing is of utter importance. 

Doctrine of Colorable Variation

The Doctrine of Colorable Variation states that someone can infringe on a patent even if they use a similar invention. Under this doctrine, there is a slight modification done to the original patented invention, although the substituted invention and the original product both yield the same result. This doctrine is used to protect a patent holder from someone who makes minor changes to an invention that are enough to make it a new invention, but the changes are not substantial enough to make it non-infringing.

According to this doctrine, if the accused party makes slight changes or modifications to the original product or process but the essential features of the substituted product are the same as those of the original product, then the party shall be held liable for infringement under the doctrine of colorable variation. The essence of the doctrine is that a slight variation in the patented invention just to show modification while the essential features are the same won’t protect the infringer from liability for infringement.

In the case of Lektophone Corporation v. The Rola Company (1930), the original product of the patent holder was a sound-reproducing instrument for phonographs. As mentioned in the application submitted by the patent holder, the size and dimension of the sound-reproducing instrument were of significant importance. It was claimed by the plaintiff that a radio loudspeaker manufactured by the defendant infringed the patent holder’s rights. The substituted product (manufacturer’s device) had a similar central paper cone-like structure. However, the size of the cone was smaller than that of the patented product. The plaintiff contended that since the defendant slightly modified the original product, it would amount to a colorable variation. However, the court held that the alteration in the defendant’s product would not accomplish the object specified in the patent claims, and there was some other machinery difference too. Thus, it did not infringe the patent holder’s claims.

Patent infringement litigation

The remedy available to the plaintiff for a patent infringement is a civil remedy, i.e., he can claim damages in the form of actual damages and reasonable royalty, along with actual litigation costs. The court, when adjudicating a lawsuit for patent infringement, follows a two-step process. The first step involves a claim construction, i.e., a written description of the specification of the patent, the entire patent prosecution story, and all the evidence available. The next step follows the investigation by the court into whether there has been actual patent infringement or not by comparing each element of the patent’s claim with that of the infringing product.

There arise certain situations when it is found that, though there has been some infringement, it seems that only some minor aspects or elements of the original invention or the patented product are found in the accused or infringing product. Under such circumstances, the doctrine of equivalents will apply in order to determine whether it will amount to infringement or not.

The infringement can also be determined by whether the differences between the invention and the infringing product are insubstantial or not. The difference between the two is said to be insubstantial if it passes the triple identity test, i.e., if both the products perform entirely the same functions in the same way and finally yield the same outcome as specified in the patented claim.

US case laws related to patent infringement

With the changing dynamics of society, and the advent of technology and modernization, along with other branches of intellectual property rights, patent law has also become a very important field of law. The thirst of mankind to grow and learn has resulted in a number of new inventions and discoveries, and patent law has evolved to be of great use. The courts have time and again dealt with the scope of infringement cases and established precedents pertaining to this branch of law. There have been numerous US case laws related to patent infringement. Even the concepts of patent infringement have evolved largely with increasing technological advancement, and thus, looking into this fact, courts have minutely dealt with different aspects of patent infringement in different case laws. Some of the most notable cases include:

Diamond v. Chakrabarty (1980)

Brief facts of the case

In the Diamond case, the defendant, Anand M. Chakrabarty, a genetic engineer by profession, made a bacterium presently known as Pseudomonas putida, which is derived from the Pseudomonas genus. The bacteria metabolize the hydrocarbons that constitute crude oil. At the time of this development, there were no natural bacteria that were capable of performing such metabolization. This developed bacteria is used for the bioremediation or biodegradation of oil. The respondent applied for a patent claim under three categories, namely; process for producing the bacteria, inoculum composed of a carrier material floating on water and the new bacteria, and claim for bacteria. The patent office accepted the first and last claims; however, it rejected the second claim. 

The respondent herein applied for the patent claims of the said development, and the US Court of Customs and Patent Appeals allowed the aforesaid patent claim. The petitioner, herein, being aggrieved by the impugned judgment allowing the patent claim, appealed before the Supreme Court.

Issue before the Court

The issue before the Supreme Court was whether the aforesaid claim falls under the category of patented subject matter. 

Judgment of the Court

The Supreme Court of the United States held that the respondent’s patent claims fall under the category of patentable subject matter, i.e., microorganisms are patentable. Thus, the aforesaid falls under the category of manufacture or composition of matter, thereby, rejecting the contention of the petitioner that the respondent’s development cannot be patented.

Aronson v. Quick Point Pencil Co. (1979)

In the case of Aronson, the petitioner filed a patent application for a new form of the key holder. The application also requested a patent for the key holder’s design. In the year 1956, the petitioner herein entered into an agreement with the Quick Point Pencil Company, wherein Aronson agreed that the defendant would manufacture and sell the petitioner’s keyholders, and in return, Aronson would get 5% of the shares, meanwhile the Quick Point Pencil Company would retain the exclusive right of creation, manufacture, and sale of the keyholder. The agreement also contained a condition that, in the event that Aronson’s patent application is not accepted within a period of 5 years, the 5% will be reduced to 2.5%. The said application was not accepted within the specified period, receiving a final rejection in 1961. The defendant company reduced the royalty as per the terms of the agreement, owing to the rejection of the petitioner’s patent application. This payment was made to Aronson for a period of 14 years. After this, in 1975, the defendant company filed to obtain a declaratory judgment in the United States District Court for the Eastern District of Missouri, stating that the agreement entered into by the parties is no more enforceable owing to the rejection of the petitioner’s patent application. The company contended that the agreement becomes enforceable owing to the federal patent law. The District Court rejected the application of the company and held that the agreement has no relation to the patent law and is hence enforceable. The company then appealed before the United States Court of Appeals for the Eighth Circuit.

Issue before the Court

Whether the agreement entered into between the parties is still enforceable even after the rejection of the designer’s patent application. The question before the court was to decide whether the federal patent policy preempts the enforceability of the agreement. 

Judgment  of the Court 

The Court of Appeals reversed the judgment of the District Court and held that the federal patent law does preempt the enforceability of the agreement entered between the parties. Since the designer failed to get a patent for her design, the agreement stands no ground and is thus unenforceable. 

Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (2002)

Brief facts of the case

In the present Festo Corporation case, the petitioning company had two patented claims for improved magnetic rodless cylinders. These patented claims were for a piston-driven device that used a magnet to move objects in a conveying system. The Festo Corporation amended its first patent application. The application was rejected on the ground that the exact method of the piston’s operation is unclear, followed by the finding that certain claims made by the corporation are in a very impermissible form. The petitioner also amended its second patent application during the process of re-examination of the proceedings. The amendment made in both applications, thereby adds a new limitation to the effect that the inventions of the corporations contain a pair of sealing rings. In the second patent,, a further limitation with respect to the composition of the outer shell, or “sleeve” of the device was added. After the sale of the inventions started, the respondent herein started selling similar manufactured products. The only difference was that the respondent’s device employed a single sealing ring, and its sleeve was made of a different material. The contention of the plaintiff was that even though the device manufactured by the defendant is not literally similar to the Corporation’s patented products, the devices are so similar that they fall under the doctrine of equivalents.

Festo Corporation filed a suit against the respondent manufacturer in the United States District Court for the District of Massachusetts. Before the final delivery of judgment, the court ordered a partial summary judgment stating that one of the infringements falls under the doctrine of equivalents. The remaining issues were dealt with by the jury, which also found the infringement and ordered damages to be paid. An appeal was filed against the judgment before the United States Court of Appeals for the Federal Circuit, wherein the decision of the lower court was affirmed. Against this, an appeal was filed before the Supreme Court.

Issues before the Court

Whether the principle of prosecution history estoppel barred Festo Corp. from claiming infringement under the doctrine of equivalents, especially when an amendment to the patent has been carried out?

Judgment of the Court

The Supreme Court held that such an amendment does not bar the petitioner from claiming infringement of its patent. However, the Court remanded the matter back to the lower court so as to determine whether the amendments carried out by the Festo surrendered the equivalents at issue or not. It is for the plaintiff to show that the amendments carried out in the patent application were carried out for a reason relating to patentability. 

Impression Products, Inc. v. Lexmark International, Inc. (2017)

In the case of Impresion Products, the Supreme Court of the United States held that the patent holder cannot sue a person for patent infringement if he has given consent for selling his product and, in such a case, it has been re-sold. As soon as the patent holder sells his product, his patent rights are relinquished, even if the item is being re-sold. In the present case, the respondent used to design, manufacture, and sell toner cartridges. In relation to this, the respondent company owns various patents in respect of different components of the cartridges. The company used to sell cartridges by way of two options, namely, buy toner cartridges at full price, thus, no restrictions, or buy the toner cartridge at a low price and enter into an agreement, thereby restraining the buyer from further transferring or reselling the cartridge. The cartridges, if bought in the second condition, could only be transferred to the respondent and nobody else. Thus, the issue before the Supreme Court was to decide whether the patentees could use a license to impose restrictions on the reselling of the product once it was sold by them.

Defenses available to the infringer or accused

The first and most common defense available to the infringer is challenging the validity of the patent, thereby contending that the patent is invalid. Some ways through which the accused can prove this is, by showing that the patentee submitted false and misleading information to the United States Patent and Trademark Office; if the patent is a result of some anti-competitive business activities; or if the accused can prove to the court that the patent did not meet the eligibility criteria as mentioned in the 35 U.S.C. like non-obviousness, usefulness, novelty, etc.

The burden of proof lies on the patent holder to show that any offense of patent infringement has occurred and that the accused is responsible for the same. The plaintiff requires a solid amount of proof to show that the defendant infringed the patent. However, once the defendant questions the validity of the patent by any means, the burden of proof shifts on him, and he must clearly show the court that any kind of fraud attempt has been made to secure the patent, or that in any way the patent lacks eligibility.

Ways to prevent patent infringement

The best way to prevent patent infringement is to protect your invention by filing for a patent. By filing for a patent, you are legally protecting your invention and giving yourself the right to sue anyone who infringes on your patent. It is important to check all the eligibility criteria mentioned in 35 U.S.C., like non-obviousness, usefulness, etc., before filing a patent application. The product that you want to get patented must be unique and should pass the test of usefulness, as discussed elaborately in the above paragraphs. It is also important that before filing the patent application, you are vigilant enough to check the existing patented products to ensure that none of the existing inventions will come your way. Once your patent application is approved, it is important that you timely pay the maintenance fees, be updated with the terms of your patents, and review your patent claims. 

In addition to filing for a patent, you should also consider other methods of protecting your invention. You can use trade secrets and copyrights to protect your invention from infringement. Getting trademarks and copyright for your invention after proper consultation with an IP attorney is important because he will acknowledge you with all the dos and don’ts of the process and will give you a better solution because of his experience in the field.  You can also use non-disclosure agreements to ensure that your invention is not disclosed to anyone without your permission. All these methods of protecting your product are important and must be assessed carefully because once you get stuck in patent infringement cases, it becomes a chaotic and costly struggle. 

Remedies for patent infringement

Chapter 29 of the 35 U.S.C. provides for provisions pertaining to remedies in cases of patent infringement. The affected party whose patented product or process has been infringed can seek remedy by way of actual damages, reasonable royalty, and/ or injunctions (permanent and temporary, as the case may be). Injunctions are court orders that prohibit an infringer from using or selling your invention. Damages are monetary awards that are designed to compensate the patent holder for any losses caused by the infringement. Attorneys’ fees are awards that are designed to reimburse the patent holder for the costs of bringing a lawsuit. The attorney’s fees (Section 285 of the Code) and all the other litigation expenses fall under the category of costs that the court directs the infringer to pay to the plaintiff once the lawsuit is decided in favor of the petitioner/plaintiff. 

Section 281 of the Code provides that the plaintiff shall have recourse to civil remedies in cases of patent infringement. The damages that are to be awarded are provided under Section 284 of the Code, and the provision for the injunction is enumerated under Section 283 of the Code. The time limit for filing a complaint or lawsuit against the alleged infringement is provided under Section 286 of the Code, which states that the complaint shall be filed within six years of the infringement act. 

What does not amount to patent infringement

Not all activities constitute patent infringement. Activities such as reverse engineering, independent creation, and experimentation are not considered patent infringement. Apart from this one, if the third party sells, imports, or manufactures any of the patented inventions as per the terms and conditions and with the consent of the patent holder, then it shall not amount to patent infringement. 

Reverse engineering is the process of taking apart a device to understand how it works. Independent creation is when someone creates an invention that is similar to a patented invention without any knowledge of the patented invention. As per the present US patent law, independent creation does not amount to patent infringement and, thus, is a good defense for the accused. Experimentation is the process of testing an invention to determine its effectiveness or reliability. Furthermore, selling or importing a patented product in the US will not amount to patent infringement if the same is done only for the purpose or in relation to the development and submission of data or information under the law pertaining to the manufacture, use, or sale of drugs or veterinary biological products.


In conclusion, patent infringement is a serious issue that affects inventors, businesses, and the public. The patented invention is the product of man’s intelligence and, thus, must be valued and protected. It is for this reason that the federal patent law was enacted under the power conferred upon Congress under Article I, Section 8, Clause 8 of the US Constitution. Patent infringement cases have witnessed a serious rise in the past few decades, and thus it becomes important for every inventor to understand these laws and thereby get their invention protected under these laws. Knowledge of these laws is not just for the attorney but for the common people too, for maintaining their product’s authenticity and protection. It is important to understand the types of patent infringement in the US and the related doctrines, US case laws, and remedies. If you are an inventor, it is important to protect your invention by filing for a patent and using other methods of protection. By doing so, you can ensure that your invention is not infringed upon and that you are able to seek remedies if it is.

Frequently Asked Questions (FAQs)

Does the concept of joint liability apply to direct patent infringement?

To prove direct infringement, it is not sufficient that various independent parties together perform the claimed process. The concept of joint liability similar to that applied in tort law is not applicable on direct patent infringement.

What are the essential requirements of proving contributory infringement?

The three essential requirements to prove contributory infringement are; knowledge to the infringer about the infringed patent, giving or inducing a third party to use any material of an infringed patented product, and the substituted product must have a component manufactured or adapted from the original patented product.

Does direct infringement require knowledge of the infringement to the accused?

In the case of Warner-Lambert v Actavis (2015), the Supreme Court of the United States held that knowledge or intent of infringement on the part of infringer is not essential for proving direct patent infringement. 


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