How to do prior art search on Google Patents

prior art search google patents

Prior Art Search: Google Patents

Google Patents Search is an extremely powerful tool for prior art search. In fact, it can be used for many purposes:

– Retrieve a patent publication whose publication number you know.

– Search for patent publications with a specific criteria (search by patent number, keywords, technology domain, etc.)

– Fetching reports that include multiple patents.

There are many other uses that Google Patents Search can serve, but I will limit the scope of this article to searching patents publications/prior art documents. It’s quite beneficial to leverage Google Patents Search by understanding how it works. This article is aimed at precisely that by explaining various features available in Google Patents and how can you use them to find patent publications.
Google Patents can be accessed form the URL –

Prior art search by Patent number:

If you know the patent publication number of a patent, you can simply enter it in the search field and find the patent publication. If you are however, looking for patent publications with specific keywords/concepts or want to do a general search in a particular technology domain, you can read through this article to understand the basics.
On the home-page of Google Patents, you will see a blank search field with a ‘bulb’ icon and a ‘hat’ icon to the right-hand side of the search field. If you want to see both patent publications and Google scholar documents, select both the ‘bulb’ and ‘hat’ icons as shown on the right-hand side of the search fields. If you want to see only patents, select the ‘bulb’ icon and not the ‘hat’ icon (vice versa, if you want to see Google scholar results).

Prior art search by keywords:

Proceed now by entering the relevant keywords or concepts in the search field. Play around with synonyms of each keyword. While doing so, remember that you can use operators such as AND, OR, NOT, (), **~* etc. to refine your search. Let us take a look at some examples:

String 1– smart AND charger AND wireless AND (phone OR mobile),

The results will include all documents that include the words – smart, charger, wireless along with either one or both of the words ‘phone’ or ‘ mobile’ (which can be synonyms in this case). You can extend this string to include additional concepts/keywords or synonyms.
If your query were – ‘smart charger wireless phone mobile’, the search tool would automatically assume ‘and’ operator between all these keywords. If you want to use ‘OR’ between some keywords, you have to explicitly indicate that by typing this operator.
Let’s look at another example:

String 2 – smart **~* charger

The operator we used in this string is a proximity operator and would find documents that include the words – ‘smart’ and ‘charger’ in the vicinity of each other. I have found this operator very effective in Google Patents as opposed to smart AROUND(3) charger, which we can normally use for Google searches. You can expect the proximity operator to find the above-mentioned keywords located within a range of 4-5 words from each other. Although paid search tools are great at this proximity operator, but Google Patents does a decent job considering it’s free to use.
Let’s consider another example:

String 3 – mobile AND device NOT charger

In the above string, you will find the documents that include the words ‘mobile’ and ‘device’ but exclude the word ‘charger’.
As a final note, in your search string try to experiment with various combinations of these operators and keywords. If you are not getting the results, try to use synonyms of each word. My personal suggestion would be not to use too many synonyms in a single string (e.g. avoid using 5-6 OR combinations at once). This may prioritize non-relevant prior arts too. Change synonyms gradually depending on the results you get!
Another aspect you should remember, there is no single best strategy in patent searching. Try multiple strategies and tools.

Search by patent classes:

Classes basically refers to classification of patent publications by their technology domains or sub-domains into respective classes and sub-classes. You can find the CPC classes here –
Class-search is useful if you are either studying a specific technology domain, or the technology domain is too vast to return relevant results or is so niche/new that even without entering the keywords, you can simply find most of the relevant patents using just the class identifier (e.g. H04W84/20 is a sub-class of class H on the above link).
You can find the class or sub-class you are looking for and enter it in the search field to find all relevant results of the preferred technology domain.
Another way you can select a class is to find some relevant patents in the domain you are searching and use their CPC class as your key string.
You can use class search either as a separate string (with one or more classes) or in combination with the keyword search.
A sample string you can use is:

String 4 – H02J7/0044 AND electrical AND charger 

As a final note, I would recommend that even before typing in your search string, think from the perspective of a patent drafter or an inventor as to how a particular concept could be written. There are multiple ways in which a concept can be articulated and sentences can be formed in a patent application. If you can spend some time thinking on various ways in which a patent application can be written, forming strings would be just a matter of typing out these alternative ways.
If you find yourself proficient with the above-strategies, you can try out Google patents advanced search for a more refined search. 
Do comment your thoughts below!