Strategies for successful prior art searching

An unoriginal technology will not only make legal protection impossible, but may also risk infringing other technologies. Attempting a prior art search can appear daunting, as it should encompass anything that has previously been made publicly available in any form, but a number of tips and tricks can be employed to help simplify the search process and determine what is a genuine advance in technology.

Database selection

The most significant starting point for any prior art search is the worldwide patent literature. There are numerous databases to use. It is important to understand which patent offices, document types and date ranges are covered within those databases, as well as any gaps in their data, so that an informed decision can be taken as to whether the search is sufficiently comprehensive.

A diligent prior art search will include both patents and non-patent literature (NPL) such as journals, conference information, industry newsletters and business reports. This can be especially important for fast-moving industries where technology can outpace the time between filing and subsequent publication of a patent application.

A platform such as Dialog, which aggregates a rich collection of patents and NPL and allows them both to be easily searched using a common search language and interface, can help bridge the gap between patents and NPL.

Synonyms and indexing

In general, patents are written to obtain legal protection and not to aid retrieval by a searcher. As patents are often at the forefront of technology there may not even be accepted words or phrases in general use to describe the key parts of the invention. So searching for a variety of synonyms as well as a combination of technical and everyday language is important.

The use of proximity search operators (such as ‘near’ or ‘within’, for example, depending on the search language) to draw words together should also be used to overcome potential issues with the legalese-style text often used in patents, such as variations in normal spoken word order.

"As patents are often at the forefront of technology there may not even be accepted words or phrases in general use to describe the key parts of the invention."

The database Derwent World Patents Index® provides clear, meaningful titles and abstracts as written by an in-house subject specialist. It can also provide distinct advantages over searching the text as published in the original patents.

Using the richness of the databases being searched can also be beneficial. Many database suppliers will index patents using their own proprietary classification schemes as well as making those employed by the respective patent offices available. The use of a variety of classification schemes will often uncover relevant prior art which may otherwise be missed.

Many search platforms provide tools to help identify an appropriate classification term to use. Alternatively, if a word search finds a key patent of interest then the classification terms on this document should be searched to expand retrieval.

Keep it simple

What may initially seem like a complicated search requirement can usually be broken down into more manageable smaller concepts which, when taken together, describe the invention. The overall search can therefore be simplified by retrieving these smaller concepts separately using synonyms, proximity operators and classification schemes to create individual sets of results.

Finally, these sets of concepts can be combined as appropriate to draw everything together into a search which encapsulates the invention. This is much easier than trying to search for the complete invention in a single search step.

Citation searching

Patent citations may come from either an applicant or a patent examiner and draw together documents with related content. Researching citations on patents of interest is therefore another entry point into relevant prior art which may be missed by other forms of searching. The iterative search process of exploring citations on citations should be repeated until nothing further of interest is uncovered.