Patent Opinion Letters
Historically, patent opinion letters were used as a shield in the case of an infringement lawsuit when one party was charged with infringing another’s patented invention. When someone claims that you have infringed their patent, they may be entitled to enhanced damages(up to three times) if the infringement was done willfully.
Most patent infringement cases are filed after one party sends another party a demand letter putting the other party on notice of the infringement. Any continued sales, manufacturing or use after receipt of the notice is arguably done willfully. To help avoid a claim of willful infringement a defending party may obtain a patent opinion letter from a patent attorney. The opinion letter can reduce the liability of an infringer. If done correctly, the opinion can act as a defense against a claim that you willfully infringed. This was typically referred to as “Advise of Counsel” defense.
However, patent opinion letters can also provide additional assistance in the case of:
- Trying to determine if a new product is within the scope of another patented product prior to launching the new product;
- Determining how to respond to a demand letter; and
- Determining the value of your intellectual property in a merger or acquisition process.
These are all questions that a patent opinion letter may be able to answer.
A patent opinion letter is different in scope and cost from a patent search. A patent opinion letter is expensive, typically detailed because you have to review what was filed in the underlying case and any potential prior art to that application and any other applications which may be used to invalidate the prior patent. To be eligible as a defense, the patent opinion must have been relied upon in good faith by the potential infringer. This means, the patent opinion must have been conducted reasonably in accordance with various best practices. In addition, by relying on advise of counsel, the potential infringer may waive privileged communications with their patent attorney. What the patent attorney relied upon in forming their opinion becomes very relevant in determining if the reliance upon advice of counsel was in good faith.