FAQ - IPC
Questions
- Is there an International Patent Classification (IPC) website?
- Who is responsible for the IPC?
- What happens when the IPC is revised? Do users have to update their search profiles every year?
- Does the classification philosophy ever change?
- If a document was published under an earlier IPC edition (1 to 7) and there has been no change in the scheme, will its new, reformed IPC classification be identical to its old IPC classification?
- Whenever the IPC is revised, how can users be sure that all documents have been reclassified in accordance with the new classification scheme?
- Have the old IPC1 to 7 classifications been overwritten by IPC8 classifications?
- What are "classification definitions"?
- Patent offices have different views and practices on IPC classification. How are the differences minimised?
- How does the family propagation of IPC classifications work?
- Is there a contact point for further questions?
Answers
Is there an International Patent Classification (IPC) website?
Yes. Information about the IPC is available on the WIPO website.
Who is responsible for the IPC?
The World Intellectual Property Organization (WIPO) based in Geneva is responsible for the IPC. It works closely with the EPO, the USPTO and the JPO, as well as other patent offices around the world on changes to the system.
What happens when the IPC is revised? Do users have to update their search profiles every year?
WIPO publishes all IPC changes three months in advance, giving searchers enough time to prepare. The round of changes made each year generally affects only a limited number of technical fields. The committee in charge of IPC revision ensures that, in any given field, changes do not occur too frequently.
Following a revision of the classification scheme, all documents (including the backfile) are reclassified. This means that search strategies aiming at retrieving a complete set of documents can be quite simple, because it is not necessary to search older material using the classification symbols of earlier IPC editions.
For some types of search, using the main group level instead of the full IPC may well be enough. Search strategies based on the main groups do not have to be adapted very often because the main groups only change to accommodate new technology.
Does the classification philosophy ever change?
In the past, classifiers focused on the claims of a patent document, which was appropriate in the days when most intellectual property offices published granted patents only. Nowadays, most offices publish patent applications before they are examined. This means that the claims at the time of publication do not necessarily reflect the “real” invention or all the material that one would like to retrieve in a search.
The IPC rules recommend that patent offices classify not only the claims, but also other important and possibly inventive aspects of the documents found, for example, in the description, examples or drawings. Any important features of this kind are to be classified as “invention information”.
Other content in a document, which, whilst being of lesser importance, may still have some search value, can be classified as “additional information”, as in the current IPC.
Before the IPC reform, the distinction between “invention information” and “additional information” was not made in most patent databases and was visible only on the printed document (separated by the “//” sign), but now it is also reflected in the databases, enabling more accurate searches.
If a document was published under an earlier IPC edition (1 to 7) and there has been no change in the scheme, will its new, reformed IPC classification be identical to its old IPC classification?
Not necessarily.
The reformed IPC classifications for documents published before 1 January 2006 were derived from different sources, most of them from ECLA.
Since EPO examiners classify in ECLA independently of the IPC classification allocated to the document, the “old” and “new” IPC classification of a document may differ.
Owing to the ECLA classification rules, which provide for more complete classification, documents may have more “new” IPC symbols than “old” ones.
Whenever the IPC is revised, how can users be sure that all documents have been reclassified in accordance with the new classification scheme?
By the time changes to the classification scheme come into effect, all documents will have been reclassified. Where this is not the case, a note in the IPC scheme provides further information.
Have the old IPC1 to 7 classifications been overwritten by IPC8 classifications?
No. The “old” IPC (editions 1-7) classifications given to documents are saved in a separate field in most databases so that users can search them independently of the “new” IPC symbols.
What are "classification definitions"?
The titles of IPC groups sometimes leave room for interpretation, and differences in interpretation have led to inconsistencies in the application of the IPC for classification and search purposes. The classification definitions available on the internet version of the IPC help classifiers and searchers to identify the classification entries relevant to a given technical subject.
The classification definitions provide a detailed explanation of the intended scope of a classification place and indicate the boundaries with other technical fields. The definitions are subdivided into seven categories, shown in the table, to make it easier for users to find the information they need.
|
Category |
More information |
|---|---|
|
Definition statement |
A more detailed explanation of the subject-matter appropriate for the classification place. |
|
Relationship between large subject-matter areas |
When the scope of the subclass is generally affected by its relationships to other large subject-matter areas (e.g. other subclasses), those relationships are indicated here. |
|
References relevant to classification in this subclass (limiting references, special adaptations) |
These references are used when subject-matter otherwise covered by the classification place is collected elsewhere in the scheme, i.e. is explicitly excluded from the place under consideration (limiting reference) or when subject-matter of the place is specially adapted, used for a particular purpose, or incorporated in a larger system (special adaptation). |
|
Informative references |
References that indicate the location of subject-matter that could be of relevance for searching, but is not within the scope of the classification place, for example references from application-oriented places to general (function-oriented) places. |
|
Special rules for classification within this subclass |
Classification rules which apply within the whole subclass or group, such as the last-place priority rule or first-place priority rule. |
|
Glossary of terms |
Significant words or phrases found in titles or definition statements. This is particularly useful when terms are used in the IPC in a more precise or restricted manner than in their common usage. |
|
Synonyms and keywords |
A list of synonyms, keywords, abbreviations and acronyms from terms used in the patent documents themselves or in technical literature. This will aid the formulation of search queries for text searching in the technical field. |
These definitions are being drawn up by experienced patent examiners from various patent offices, with the EPO as a major contributor. Of course, this process will take a while. Currently, only a part of the IPC classification entries (some subclasses and main groups) have definitions. WIPO and the major patent offices will continue to add to these definitions.
Patent offices have different views and practices on IPC classification. How are the differences minimised?
With the introduction of IPC definitions, the intended scope of IPC classification places is much clearer and leaves less room for interpretation. This should lead to a more consistent application of the system.
In 2006 the IPC codes for the backfile were derived from only a few sources, and were not necessarily based on the “old” (pre-2006) IPC classification given on publication, so the generated IPC classification of these documents is likely to be more consistent than the original IPC classification.
Whenever the IPC is revised, the documents are reclassified by a small number of offices and the new classifications are propagated to all members of a patent family. This also helps to limit variations in how the IPC is applied.
How does the family propagation of IPC classifications work?
The goal of the reformed IPC is to provide a single classification that can be used for searching the whole document collection.
This requires reclassification of documents. There was a major reclassification exercise in 2006 when the IPC was reformed, and further reclassification takes place each time the IPC is revised.
To reduce workload for the offices doing the reclassification, only one representative document per patent family is actually reclassified and the classification data of this document is propagated to its family members.
There are different definitions of a patent family:
- Simple family: all documents having an identical set of priority data.
- Extended family: all documents having at least one priority application in common.
- INPADOC family and family definitions applied by commercial databases.
These are variations of the extended family and the explanations below also apply to these concepts.
For the propagation of IPC classifications, the simple family is taken as a basis, i.e. a classification given to a patent document during a reclassification exercise is copied only to documents having exactly the same priorities.
Example 1:
The following documents form a simple family:
|
Pub. No. |
FR2868297 |
JP2005298500 |
CN1679507 |
|
Priority No. |
FR20040050695 |
FR20040050695 |
FR20040050695 |
A classification given to document FR2868297 would be copied to the two other documents.
Example 2:
The following documents are part of the extended family of the documents in example 1 (all having a common priority), but form a simple family of their own:
|
Pub. No. |
EP1584322 |
FR2868295 |
|
Priority No. |
FR20040050695, |
FR20040050695, |
A classification given to document EP1584322 would be copied to the document FR2868295.
However, a classification given to document FR2868297 of example 1 would not be copied to these two documents.
This principle only applies to reclassifications, i.e. when the existing IPC classification of a document is changed. All newly published documents from 2006 onwards receive their own IPC classification from their publishing office, with the consequence that such members of a simple patent family may have different IPC classifications.
They will undergo family propagation only when reclassified in the light of an IPC revision.
Is there a contact point for further questions?
If you have any questions about the IPC, especially if are concerned about how to apply it in the products you use, please contact us. You will find further information on the IPC itself on the WIPO website.