How to deliver top-quality prior art without overstretching your budget

“We don’t have an endless budget. We can’t boil the ocean.” (Fitbit, Inc v Smart Wearable Technologies Inc (inter partes review 2018-00252)). Any patent searcher or patent practitioner has heard this phrase. The world simply has more content than one could ever review. Most inter partes reviews rely on US patents for prior art. This is due to the perceived difficulty of confirming the public availability of a non-patent document and because the US patent corpus offers a centralised and organised concentration of written knowledge. However, critical prior art disclosures often lie in non-patent literature (NPL), which contains published technology standards specifications and related working documents or ex-US patent publications (eg, Japanese utility models or Patent Cooperation Treaty applications). Notwithstanding concerns about accurate timestamping, widening the scope to include these additional coverage areas can come with budget constraints. Further, keyword searching is grossly inferior to manual searching by a trained expert. Compound this with an expansive volume of documents and there is a significant challenge over where, what and how to search.

Where and what to search?

In order to be cost and time efficient, it is essential to focus a prior art search on sources that are most likely to be useful. This means basing the search on the state of the technology before the priority date in various countries, the players developing the technology, and having a deep understanding of how different technological regions are documented around the world. For instance, countries that operate on a first-to-file basis train their engineers not to write articles, but to focus largely on filing patents (eg, Japan and some European countries). Technology development trends further narrow the options – when addressing semiconductor processing technology before 2000, the prior art will likely be in either the United States, Japan or in a few European countries only. It is wasteful, as evident in these examples, to conduct a high-level worldwide search when a targeted, thoughtful search of select jurisdictions and select document types could be deployed. Knowing where and what to search, particularly 10 to 15 years into the past, comes from years of experience observing the incremental development of an industry and its underlying technology. Further, deep experience is required to understand where different technologies and different jurisdictions publish.

A real example of an effective NPL search is related to inter partes review 2018-00252 for US Patent 6,997,882 to Parker, which covers wearable sensors for activity monitoring. Here, Fitbit Inc was attempting to invalidate Claims 8 to 10 asserted by the patent owner, Smart Wearable Technologies Inc against Fitbit and other defendants in co-pending district court cases. Despite an extensive body of cited art, a key element of Claim 8 of Parker was not disclosed elsewhere. Parker stated that “[prior to this invention, the advantages of 6-DOF (Degrees of Freedom) accelerometry had not been extended to subject monitoring” due to “substantial technological hurdles”, such as the requirement of  “considerable additional computational effort”  to process large amounts of information very quickly.

Based on past cases, which pertain to wearable sensors, movement activity and health monitoring, the following sources were identified as the most fruitful – non-patent technical publications including key journals, conference proceedings and dissertations as well as a fresh look at US patents. This effort identified several promising patents and non-patent references, one of which was a conference paper from Computers in Cardiology – Ng et al, "Sensing and Documentation of Body Position During Ambulatory ECG Monitoring”.  While the publication was indexed by IEEE Xplore, several key teachings resided in the paper’s figures only; namely correlating an individual’s sensed movement with other sensed “physiological characteristics of an individual”.

Ultimately, Fitbit prevailed in obtaining a final written decision from the PTAB rendering Claims 8 to 10 unpatentable over Ng in combination with other references. It is worth noting that previous inter partes reviews were dismissed prematurely as the parties settled prior to final written decision.  One of those inter partes reviews, filed by TomTom, Inc (See inter partes review 2017-01826), settled after the PTAB instituted a review of Claim 8, which was the only challenged claim.


In this case, a broad keyword search can identify a large number of documents from likely non-relevant sources and yet miss this reference where the key claim limitation was recited in an exhibit only. It is clear that aligning the ‘how’ (ie, manual searching by a technical expert) with the ‘where’ and the ‘what’ (ie, conference papers in the medical domain) can deliver killer prior art without having to boil the ocean.

This is an Insight article, written by a selected partner as part of IAM's co-published content. Read more on Insight

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