Patent Litigation FAQ

Austin Patent & Trademark Attorney

Patent Litigation FAQ

Frequently Asked Questions

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What does a plaintiff have to show to prove patent infringement?

To prove infringement a plaintiff must show the defendant made, used, sold or imported a technology that features all the elements of the plaintiff’s patent claims. If the claims of the plaintiff’s patent require three elements, then the plaintiff will have to show that the defendant’s technology used each of those three elements. This is what is known as a case of “literal infringement.”

If a plaintiff cannot show literal infringement because the defendant has substituted one element that is not identical to what is in the plaintiff’s claims, then the plaintiff may have to rely on a theory known as the “doctrine of equivalents.” This is the legal equivalent of arguing “close enough.” This doctrine has been severely limited by a line of cases that discuss “file wrapper estoppel.” Amendments and arguments made by the patent applicant during the process of securing a patent can limit the interpretation of his or her claims.

What types of relief are available to a patent holder who proves that a defendant infringed a patent?

A successful patent plaintiff may be entitled to an injunction, money damages, exclusion orders, or seizures of infringing goods.

How are damages calculated in a patent case?

Money damages in a patent case are typically categorized by either of 1) plaintiff’s lost profits; or 2) a “reasonable royalty.” In most cases expert witnesses are called in for purposes of establishing one of these two models. The first model relates generally to what a plaintiff could have made in profits had it not been for the defendant’s infringements. The second model is often used when the plaintiff does not have a history of sales and so relies on a hypothetical determination of what the infringer should have paid for a license to the patented technology. For design patents, a different damages model may be used which involves stripping a defendant of profits made from the infringements.

Are punitive damages available in patent cases?

Yes. If a plaintiff can show that infringement was intentional or “willful” then enhanced damages may be awarded. A defendant who was aware of a patent but continued the conduct of selling infringing products may be liable for willful infringement.

What defenses are available against allegations of patent infringement?

A primary defense to allegations of infringement is simply to prove noninfringement. The accused products do not infringe if they do not feature each of the elements of plaintiff’s claims. The complexity of this analysis will depend on the complexity of the technology.

Other defenses may seek to challenge the validity of the patents in question. If a defendant can show that the patents in question were not new, useful, or that they were obvious at the time the patents were granted, then it may be possible to invalidate those patents. Defendants will often research public records and patents for proof that the technology was not new at the time of the claimed invention.

If a defendant can show that the patented technology was actually on sale, publicly known, used, or offered for sale more than a year before the patent holder filed for a patent, these facts may also serve to invalidate a patent.

In some cases, if the defendant can show that the patent owner engaged in unethical or fraudulent conduct at the patent office to secure the patent, this can also be a basis for a defense.

Are all patent cases resolved in federal court?

No. While federal court is still a primary venue for patent disputes, patent disputes are often resolved in arbitration proceedings. Also, patent-related issues can arise at the International Trade Commission (“ITC”), which has the power to issue exclusion orders to keep infringing technologies from being imported into the country. In some cases, United States Customs will be involved in patent disputes if it is required to make a seizure of goods that are believed to be infringing.

Also, the United States Patent Office may consider a variety of pre-and post-issuance challenges to the validity of a patent. Historically, these were known as “re-examination” proceedings and they were entertained if a challenger could show that a prior art reference or publication raised a substantial new question about patentability. Sometimes federal courts would defer to the Patent Office or vice versa in the event of parallel proceedings on the same subject matter. The America Invents Act of 2012 introduced new procedures to challenge patents at the patent office at the Patent Trial & Appeal Board (“PTAB”). These include what are known as a “post-grant” review; an “inter partes” challenge, and a pre-issuance challenge. Use of these proceedings should be explored carefully.


What is claim construction? What is a Markman hearing?

Claim construction is the process of interpreting the language in patent claims. What claims mean is not always obvious because of the nature of our language and the fact that inventors have a right to create terms to define their own inventions. Furthermore, arguments made to the Patent Office can often change the meaning of claim terms in a patent. Consequently, the claims have to be interpreted carefully.

What happens in a case of patent infringement after the claim construction phase?

Usually following the claim construction phases of a trial, the parties will move into an extensive discovery phase of the litigation aimed at proving or disproving that the accused product reads on the claims as construed by the Court. A defendant will also generally be looking for evidence that may invalidate the patent or otherwise defeat enforcement. This phase is usually characterized by extensive evidence gathering or “discovery” including document subpoenas, document reviews, depositions of witnesses, and development of expert testimony.

A Markman proceeding is the vehicle that courts use to interpret these claims. In some cases, a Markman proceeding will be a ruling on briefings submitted to the court, whereas in others a Markman proceeding will be more like a trial with witnesses, opening/closing statements and evidence. The federal courts vary considerably across the country with how they handle Markman proceedings. At the Markman proceeding, the courts will look at the language of the claims, the history of arguments made to the patent office to get the patents, the scope of prior art patents considered during examination, and sometimes will consider testimony from witnesses about ambiguous terms.

What should we do if we received a cease and desist letter?

You should contact an attorney immediately who is familiar with patent litigation. To perform a proper analysis of your risk, it will most likely be necessary to conduct an infringement assessment and secure an infringement opinion. How you respond to the threat will depend very much on the merits of the allegations.

If you have an intellectual property matter that you would like to discuss with the attorneys of Buche & Associates P.C., please do not hesitate to contact us for a free consultation.

Patent Attorney in San Diego