What is Patent Infringement?

We need to understand whether patent infringement has occurred or not, and in order to verify the infringement it is necessary to determine the scope of protection of the patented invention, basically from the patent specification and patent claims. Thereafter, it is important to study the interpretation of the wording ("literal infringement"), which is the basic rule of patent infringement. What is meant by literal infringement? Literal infringement is nothing but when all the elements in the infringing product are present in the claimed product. Sometimes, assessing literal infringement only would not establish the grounds of patent infringement. Even though some elements may not be literally infringing, we will have to study whether the elements are "performing substantially the same function, in substantially the same way, and accomplish the same result". This step is referred to as, the "doctrine of equivalence". The above analysis can be performed with the help of patent attorneys/patent lawyer, who has the techno-legal background.

Do you know who is liable for patent infringement? Your answer may be the actual manufacturer of infringing product, but also the users of the patented invention or others who are indirectly connected with such infringing activity, are liable for infringement.

There are various ways of establishing patent infringement and a suit for infringement must be instituted within 3 years from the date on which the plaintiff first knew the infringement (Under Section 88). The plaintiff can be i) the patentee, i.e., the person registered in the Register of Patents as the grantee or proprietor of the patent, or ii) t he holder of an exclusive license provided the license is registered, or iii) The holder of a compulsory license; in the event the patentee fails to institute proceedings on the request of the compulsory license holder, or iv) an assignee of a patent provided an application for registration of assignment has been filed before the date of filing the suit; or v) a co-owner of a patent is not expressly entitled in the Act to bring an action for infringement on his own without joining the others.

Now, the question of interest would be whether a third party would be liable for an infringement if the patent has lapsed. The answer is not liable for an infringement. The immunity is from the date on which the patent has lapsed till the application for restoration, if filed, is advertised in the official gazette. In case the patentee has not cared to restore his patent within the prescribed period, the patent lapses and the invention would become the public domain.

In case any person receives notice of infringement, the person should take the following necessary steps: i) first find out the patent number of the invention from the person who sent the notice; ii) check the patent is in force or not from the patent office; iii) check if the person who sent the notice is the registered proprietor of the patent; iv) in case the above steps are positive, procure a copy of the specification from the patent office and study it in detail, and v) if the patentee (the person who sent the notice) has a good case, the person should either drop the working of that invention or attempt at procuring a license from the patentee.

Finally, I would like to point out that the patented invention can be used for research purposes without any liability for infringement.