Search procedure

The examiner's work begins in the search phase, which identifies previously published technical disclosures that will be relevant for assessing the patentability of the invention described in the patent application.

1 Studying the patent application

At the start of the process, the examiner studies the description, claims and figures to:

  • understand the technical contribution of the invention (the technical essence of the invention) on the basis of the information contained in the application
  • understand the scope of the claims
  • identify possible lack of unity 
  • in the case of lack of unity, identify the different inventions (only the first will be searched at first and the applicant has to pay additional search fees if they want the other invention searched at a later stage)

statements or assertions defining the object of the invention. Though sometimes very long, they always consist of one single sentence. The claims define the scope of protection attached to the patent, e.g. a claim directed to "a car with five wheels" would entitle the patent proprietor to claim rights for any object that can be called a car with five wheels.
Lack of unity: when more than one invention is claimed in a patent application there is said to be a "lack of unity". For example, if claim one is directed to a cellular phone with an improved keyboard and claim two to a cellular phone with an improved antenna, there are two inventions. The first inventive concept is linked to the improved keyboard, the second to the improved antenna.

2 Classification of the patent application

The patent application is assigned a specific class within its technical field. The EPO uses the European Classification system (ECLA).

all patent applications are classified by the area of technology, organising them for retrieval.

3 Definition of the search strategy

The examiner has to decide on a strategy for the search, by:

  • selecting the databases
  • selecting the classes in which to search and/or the keywords to be searched 
  • contacting experts for further classes or advice (optional)

Usually various search strategies are possible, and the examiner should exercise his judgement and experience to select the search strategy most appropriate to the case in hand.

contain technical documents, mainly patent publications but also articles from technical magazines, books, etc. Sometimes the databases only contain abstracts of these documents, but often they also include the full texts.
Selecting the classes: it may be necessary to search in more than one class in the databases. For example, documents relevant for a laser cutting device would be classified under B23K26/00dD but similar devices might be found in the class relating to laser welding devices.

4 Implementation of the search strategy

Once the strategy is decided, a search result is extracted from the databases, consisting of a set of documents published before the date of filing of the patent application, showing prior art.
The examiner may need to re-formulate the subject of the search as he evaluates the results.
Reasons of economy dictate that the examiner use his judgement to end the search when the probability of discovering further relevant prior art becomes very low in relation to the effort required.

Prior art:
technical matter known before the patent application was filed at the patent office.

5 Detailed evaluation of the documents found

The examiner looks at the set of documents (normally on screen) and selects relevant documents (e.g. 20 documents) from the set.
The examiner then evaluates the set of documents and extracts the most relevant documents, disclosing the same or a similar invention to the one claimed, or disclosing the same or a similar essence of the invention.

Relevant documents
 are documents that appear at first sight to disclose technical matter similar to the invention disclosed in the patent application.
Most relevant documents: the set is reduced, e.g. to four documents only.

6 Substantive examination of the application

The examiner examines the application to check:

  • if the claims are clear (understandable, non-ambiguous, complete...)
  • whether the invention as claimed is novel over the most relevant documents found
  • if so, whether it involves an inventive step (would it have been obvious for a skilled person looking at the most relevant documents to arrive at the invention as claimed?)
  • whether the application meets other relevant requirements of the European Patent Convention

Although the application procedure is officially divided into the search and examination phases, much of the initial examination work actually takes place during the search phase.
Novelty: a requirement for the grant of a European patent. The invention claimed must be new, i.e. not form part of the state of the art.
Inventive step: a requirement for the grant of a European patent. The invention would not be obvious to someone skilled in the art.

7 Writing and issuing the Extended European Search Report

The examiner then writes the search report

  • listing the documents found and the relevant passages thereof (possibly those referred to in the search opinion),
  • assessing the relevance for the claims of each document (on the basis of the statements made in the search opinion), and
  • indicating the IPC class relevant to the application. 

The search report is published together with the application and sent to the appliant. The search report for most applications is accompanied by a search opinion. Together they are known as the Extended European Search Report.

Search report:
provides information on the relevant state of the art to the appliant, Examining Divisions and the public. An example is included at the bottom of the page.
IPC: International Patent Classification
Search opinion: outlines why the examiner believes that the application or invention does not meet the requirements of the EPC. The examiner may suggest ammendments to overcome the objections (example(PDF)).

8 End of Search Procedure

After the search report has been published, the applicant has six months to decide whether he wants to continue with the application. Once the applicant pays the examination fee, the examination procedure begins. If they do not pay the fee, the patent application is deemed withdrawn.

The application is published together with the search report if the search report is ready within 18 months of the data of filing of the application. Otherwise, the application is published without the search report (but with an indication of the IPC classification, which must be done by the examiner) and the search report is published later.


Of the four documents found, the first describes the same invention as claimed in claim one. The other three are merely technological background. The search report would indicate the following (X meaning very relevant, A meaning technological background):