Proving patent infringement

BY ALEJANDRO LUNA, PARTNER
MANAGING INTELLECTUAL PROPERTY, INTERNATIONAL BRIEFINGS, JULY/AUGUST 2002
The Mexican Industrial Property Law (IPL) grants a patentee the right for the exclusive exploitation of the patented invention. Therefore, the patent gives the right to exclude others from making, using, offering for sale or importing the covered invention. Briefly, in a patent infringement action the plaintiff must prove the following:
  • Ownership or recorded licence over a granted, valid and fully in force patent. Generally, a certified copy of the file wrapper of the patent prosecution is enough to prove these requirements. However, the defendant may challenge the validity of the patent.
  • That someone uses, manufactures, sells, or imports the patented invention. The Mexican IPL establishes direct infringement over the manufacturer. However, infringement against sellers requires evidence of prior notice of the alleged infringement. When the plaintiff claims infringement of a patented process, the defendant has the burden of proving the use of a different process. There are no grounds in the IPL to apply contributory infringement doctrine, namely action against persons who assist in patent infringement.
  • The use of the patented invention. Pursuant to the Mexican IPL only literal infringement is recognized, no infringement under the doctrine of equivalence is provided. The plaintiff should prove that the wording of the patent’s claim of claims covers the alleged infringer’s product or process.
First, the plaintiff must define the scope of the approved claims. The IPL provides that the breadth of the claims is determined by the wording, aided by the description and drawings.
Interpretation of the claims and the use of the patented invention in the accused product or process are technical issues. Therefore, infringement actions require proof from experts even though the corresponding Technical Center of the Mexican PTO may render a technical report as an expert in patent matters.
The burden of proving authorization is on the defendant. The doctrine of implied licence has never been tested before the Mexican courts.
Finally, proving patent infringement in Mexico is a difficult task in a country that follows a strict civil law system of formalistic rules for both evidence and proceedings.