Patent Invalidation or Opposition Search is conducted to question the validity of a patent. Mostly it is conducted by defendants to invalidate plaintiff's patent in a patent infringement lawsuit; or when a patent application for a similar invention owned by someone has been filed by a third party. Invalidity search is focused around the claims and file history of the patent to be invalidated. In addition to revoking a patent/application, invalidity searches help perform IP due diligence.
Most straight forward method of invalidating a patent is to attack its novelty by presenting a prior art literature that has been present in the public domain before the first filing date of the patent application. This, however, is not always possible and often difficult to identify a carbon-copy (or novelty destroying) prior art. In such cases, the most frequently adopted method is to question the non-obviousness (or inventive step) of the target patent’s invention. In most jurisdictions, it is done by finding two prior-art literature and checking whether upon combination it covers the novelty aspect of the target patent’s invention.
This sounds like an easy task, but the main challenge lies with finding the appropriate prior arts that may attack the novelty or inventive step of the target patent. Most searchers start their search with patent documents in paid patent databases starting with broad searches and then narrowing it down (top to bottom approach) or starting with narrow patent searches and then broadening it up (bottom to top approach) depending upon the subject matter to be searched, followed by a non-patent search. Also, there are some searchers who start with a non-patent search (followed by patent search) to understand the technology domain, competition, main players in the technology domain, main inventors, similar products or finding prototypes in videos (on YouTube). Conducting both patent and non-patent literature searches is an essential feature of a comprehensive patent invalidation search.
However, despite following a well-structured plan for both patent and non-patent search, it is sometimes very difficult to identify any closely similar prior art. We, at Boolean IP, call such patents as perfectly drafted patents. For such cases, we gladly accept the challenge and find fun in invalidating such patents.
In a recent patent invalidity search, when our team was exhausted with everything they could do on paid databases for patent or non-patent literature, we chose to look at conference presentations. After a thorough searching and analysis, we found a document (in PDF form) that contained the pictures of hand written notes describing the subject matter of the target invention that was disclosed in a conference presentation. The date on which those notes were taken was well before the first filing date of the target patent. The document helped locate some further information about the contents of the conference. The document was a bang-on killer art and it helped in an easy out-of-court settlement for infringement lawsuit against our client. When we checked why that document wasn’t captured earlier in our search strategy (although it should have been), we found that since the subject matter was present in a pictured form of hand written notes in a PDF format, most databases couldn't have captured and deciphered it.
Maybe we got lucky, or it was truly a hard work of our team. But we learnt a lesson that you cannot always depend on databases all the time, and reviewing conference presentations specifically the handwritten notes are a must for any patent invalidation search.