Defensive Patent

A defensive patent is one that is registered not with a view to enforce it to generate royalties, or to exclude competitors, but to provide protection from litigation.

Defensive patents can protect their holder in two ways:

  • By allowing the holder to counter-sue.
  • By preventing others from applying for the same, or similar, patents.

The companies best placed to use patents to counter-sue are those with big patent portfolios. The larger the portfolio, the better the odds that the party from which a defense is needed is in fact infringing one of the defenders patents.

A weakness of defensive patents (in allowing counter-suits) is that they are only effective against those who have businesses that use the technologies covered by the defensive patent portfolio. It is less effective against companies that primarily operate in a different (from the defender) industry, and useless against patent trolls.