Espacenet Searching: The Bare Essentials

This ultra-lite and highly unofficial ‘get you started’ guide here to the European Patent Office's Espacenet is no substitute for the help on Espacenet itself. We know it gets results but we’re not you, so rely on it at your peril.

Let’s first summarise what you’re going to do.

  1. You’ll use your keywords to find at least some relevant patents, then sift through them one by one. This may be all you need to do to find prior art.
  2. If (1) doesn’t do the job, you’ll now use some of the patents you’ve found as a stepping-stone to the relevant EC classification(s) for your idea. The European Classification or ECLA system organises patents by subject and can give better results than keywords alone.
  3. You’ll retrieve all patents in each relevant EC classification - possibly refining your search with keywords - to produce searchable ‘hit lists’ of all patents in the same technology area as your idea.

  • Using keywords

    Using your list of keywords, prepare search strings of up to four keywords, using any allowable Boolean operators and perhaps especially using Espacenet’s wildcard facility to find plurals and other variants. (For example: to find ventilator(s), ventilate(s), ventilated, ventilating and ventilation all at one go, just key in ventilat*.)

  • Getting to a results list

    • Go to and click on Quick Search.
    • From the Quick Search ‘Select patent database’ menu select Worldwide.
    • At ‘Select what to search’ click on 'Words in the title or abstract'.
    • Key your search string into ‘Enter search terms’.
    • Click Search and in a few seconds you’ll get a results list

    Is it the right results list?
    • If an inspection of titles says yes, work through it patent by patent, applying some or all of the 20 steps below.
    • If it’s not a useful list, go back to Quick Search and try a different search string.

  • Searching company names

    If the technology area you want to search is dominated by a few major companies, they’ll own at least some relevant patents, so it might be useful to start by looking at what they've got.

    • On the Quick Search page, at ‘Select what to search’ click 'Persons or organisations'.
    • In the ‘Search term(s)’ field enter the company name.
    • Click Search to get a list of all patents registered to that company.
    • If the list is long, combine the company name with ECLAs and/or keywords (steps 8-20) to find relevant patents.

  • Working with the results list (STEPS 1-3)

    1. On your results list, click on a title that looks possibly relevant. This opens up a screen that should include an Abstract and, with luck, a sample drawing. One or both may be all you need to decide whether that patent is relevant. (To quickly see more drawings, click Mosaics at the top of the screen.)
    2. If that patent clearly isn't relevant, try another title from your results list.
    3. If the screen doesn’t tell you enough (some Abstracts are as clear as mud, and drawings don't always show anything easily recognisable), you may need to examine the patent itself. Click Original document.

  • Examining individual patents (Steps 4-6)

    When the patent opens, take note of two useful links:

    • Maximise gives you a larger page view with a drop-down menu for easier navigation of the patent. (And at the time of writing, Maximise plus Safari is an essential combination if you’re using an Apple Mac.)
    • Save full downloads the whole patent as a PDF. The normal toolbar Save or Print commands only give you single pages.

    1. Read the introduction to the patent. This usually sets the scene by describing the problem the inventor has set out to solve, and its technology environment. This can often be a better guide to relevance than drawings.
    2. Still unsure about relevance? From the patent's drop-down menu select Claims. These are the breakdown of the idea into all its alleged inventive steps. Claims can be tricky to interpret but they determine the commercial strength of a patent and so are extremely important. Do any of them sound like the claims you might want to make for your own inventive step? If so, the patent may be prior art as you won’t be able to claim what has already been granted to someone else.
    3. Still unsure about relevance? By now you’re running out of options. You may just have to bite the bullet and read the whole patent. (Some are very, very long.)

  • Broadening your search (Step 7)

    1. From the drop-down menu select Search report or SR if there is one. It's usually
      at the end of the patent. If it isn't there (unhelpfully, US patents don’t have them) look for a Search report or References cited list on the front page of the patent. Search reports list patents that official examiners have regarded as relevant, so thanks to an examiner’s diligence you may find crucial patents that might not be on your results list.

    By working through your results list repeating steps 1-7, you may soon find enough prior art to stop searching and declare your inventive step a goner. But if no obvious prior art is coming up, or if you sense that keyword searching is too haphazard, try shifting the basis of your search from keywords to subject classifications.

    To do this you could use Espacenet’s Classification Search facility, which lets you use keywords to find classifications. While this may seem simpler than the method we’re about to describe, the inexactness of keywords can make it all too easy to get the wrong classifications or miss others that are relevant. Try it by all means, but we think it’s better to find the right classifications via patents you know to be relevant.

  • Using ECLAs (steps 8-15)

    1. Go back to the Bibliographic screen of the most relevant patent you’ve found and click its ECLA or Classification: European number. If there isn’t one for that patent, try another relevant patent.
    2. For each ECLA – more than one per patent isn’t uncommon - go through the following routine.

    Finding your first classification
    1. After clicking on the ECLA a screen appears highlighting that classification. Does it or any of its near neighbours sound relevant to your idea?
    2. If yes or maybe, check the box alongside the classification. Its number should automatically appear in the ‘Copy to search form’ field. Click Copy.
    3. You’ll now be taken to the Advanced Search page with the ‘European Classification (ECLA)’ field filled in. Click Search.
    4. You now get a list of all patents in that classification.

    Examining your results list
    1. Check through them, exactly as you
      did with your keywords results list. This time you should find a higher proportion relevant to your idea. If not, you may need to look for other ECLAs.

    Finding other classifications
    1. There may well be more than one relevant classification for your idea, so repeat steps 8-14 with other relevant patents from your keywords search lists. If the same ECLAs keep cropping up, there’s a good (but not guaranteed) chance that you’re not missing any other important classifications.

  • Refining and completing your search (Steps 16-20)

    Have you ended up with very long ECLA lists? Try adding keywords to refine your search.

    1. Go to the Advanced Search screen.
    2. Key in the ECLA that gave you a bloated results list.
    3. In one of the ‘Keywords (in)...’ fields add one or more of your keywords and click Search.
    4. With luck you’ll get a much smaller number of more relevant patents.
    5. If necessary, keep repeating with different keywords added.

    For example: we want to find all patents for mousetraps. Mousetraps are in ECLA A01M23 ‘Traps for animals’, which on the date we searched held a daunting 4583 patents. But searching again for brought the number down to a much more manageable and relevant 269 (of the other 4314, at least one was for an elephant trap). If we didn’t find our inventive step within those 269, we might try again with, for example, A01M23 + rodent*, or rat*, or bird*, or ‘small animal*’... get the idea? Try all possible ECLA + keyword variations. In general, the skill in searching is to narrow your search down as much as possible without inadvertently excluding something that might be relevant.

    Completing your search
    By eliminating numbers from your search results lists and adding new ones you pick up along the way from official search reports, your search becomes steadily more thorough and effective. If you finally run out of patents to look at and still haven’t found prior art that delivers a knockout blow, you can conclude with reasonable confidence that your inventive step may be novel. (As you’ll discover later, there’s no such thing as certainty when it comes to novelty of invention.)

Let Others Do Your Patent Searching

If you conclude that you don’t want to do your own patent searching or that you want your findings checked professionally – we’d certainly recommend using professionals from the start if you can afford it – your options include using:

  • A patent attorney. Find one from your phone directory or via the Chartered Institute of Patent Attorneys ( Fees vary according to the type of search you need.
  • The Intellectual Property Office’s Search and Advisory Service. Options and costs vary.
  • The British Library’s search services. Options and costs vary.
  • The search services of one of the Patlib UK network of specialist patent libraries. Options and costs vary.
  • Our own invention assessment service, which includes a patent search. Fixed fee.
  • Online search services offered by local libraries, universities and business advice centres – too many to list – often at very
    low cost. Many of these will however simply be Espacenet or other database searches performed with varying degrees of skill. Such a search may be a bargain if it turns up indisputable prior art, but be cautious about accepting a ‘nothing found’ report as gospel.

It should be possible to find something you can comfortably afford. Costs can often be reduced if you do at least some of the groundwork yourself - for example by preparing a clear description of your idea and a list of possible keywords. Search cost shouldn’t however be the sole factor. The real skill in patent searching lies in interpreting the findings, and this may be difficult for a novice. A professional search and opinion may cost more initially but may be better value in the long run.

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