Priority under the European Patent Convention (EPC)

Under Article 87(1) EPC, a claim in a patent (application) can benefit from a right of priority of an earlier application for the same invention. This has the effect that the filing date of this claim ("effective date") is deemed to be the filing date of the earlier application (Art. 89 EPC) for the purposes of determining the state of the art. To qualify for this benefit, certain requirements must be met. Claiming priority is subject to certain formalities. Because of the strict interpretation of "the same invention", claims that are not literally disclosed in the earlier application are unlikely to have the benefit of priority.

Requirements for a valid priority claim

Article 87(1) EPC gives the legal basis for a valid priority claim.

A person, [or his successors in title,] who has duly filed in or for any State party to the Paris Convention for the Protection of Industrial Property, an application for a patent or for the registration of a utility model or for a utility certificate or for an inventor's certificate, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application.

A person or his successors in title

The right to priority can only be claimed by the applicant of the priority application, or by a person to whom the right to priority has been transferred (Art. 87(1) EPC, J 19/87, J 11/95, Guidelines A-III 6.1). This right can be transferred independently from the priority application itself, but it cannot be transferred to two different persons.

The earlier application or the right to priority must have been transferred before the filing of the European application claiming priority. If there are multiple applicants, it suffices that one of them was applicant of the priority application or has had the right to priority transferred to him (Guidelines A-III 6.1).

In or for a State party to the Paris Convention

The earlier application must be made in or for a State party to the Paris Convention (Art. 87(1) EPC). It is not possible to claim priority from applications in or for States that are not a party to the Paris Convention, even when such States are member of the WTO (this issue has been referred to the Enlarged Board, G 2/02, G 3/02). This is different from the situation in the Patent Cooperation Treaty (PCT), where Rule 4.10(a) also allows priority of application(s) filed in or for Members of the World Trade Organization that are not members of the Paris Convention. The EPO has declared this Rule is incompatible with the EPC (PCT AG-I 97).

Priority may be claimed of any application that is equivalent to a regular national filing (Art. 87(2) EPC, Guidelines C-V 1.3). A European application is equivalent to a regular national filing in the designated EPC Contracting States (Art. 66 EPC). The same goes for an international application under the PCT (Art. 11(4) PCT, AG-I 48).

An application for a patent

The earlier application may be for a patent or for the registration of a utility model or for a utility certificate or for an inventor's certificate (Art. 87(1) EPC). Registered design models (e.g. the German Geschmacksmusters), trademarks or applications for same are not a valid basis for priority (J 15/80).

Any filing that is sufficient (under national law in the country where filed) to establish the date on which the application was filed, gives rise to a right to priority (Art. 87(3) EPC). It does not matter what the outcome of the application was. For example, it may subsequently be abandoned or refused or be deemed withdrawn for failure to pay any fee. A U.S. provisional application for patent is a basis for priority in Europe even though it cannot become a patent (OJ 1996, 81).

A European application may claim rights of priority from on more than one earlier application (Art. 88(2) EPC). The earlier applications may be made in different countries. Article 87 EPC permits the claiming of "inner" priority. That is, priority can be claimed from an application in a country that is designated in the European application (Guidelines A-III 6.2). The Paris Convention only deals with claiming of priority in applications in the other countries (Art. 4A(1) PC). PCT also allows inner priority (Art. 8(1) PCT).

The same invention

The European application claiming priority of an earlier application must relate to the same invention as the earlier application (Art. 87(1) EPC). The right of priority exists for any matter disclosed in the earlier application as a whole, not just for matter claimed in the earlier application (Art. 88(4) EPC).

A claim in the European application can benefit from priority of an earlier application only if the skilled person can derive the subject-matter of the claim directly and unambiguously, using common general knowledge, from the earlier application as a whole (G 2/98). This means that all elements from the claim must have been disclosed, explicitly or implicitly, in the earlier application. The basic test to determine whether a claim is entitled to the date of a priority document is the same as the test of whether an amendment to an application satisfies the requirement of Art. 123(2) EPC.

For some examples, see below at Priority problems in practice.

The earlier application must contain an enabling disclosure of the invention (T 206/83, T 81/87).

During a period of twelve months

The European application claiming priority of an earlier application must be filed within a period of twelve months from the date of filing of the earlier application (Art. 87(1) EPC). This period is computed in accordance with Rule 83(4) EPC. If the priority period ends on a day on which the EPO is closed, the period is extended until the first day the EPO is open again (Rule 85(1) EPC). The same goes for interruptions in the mail (Rule 85(2) EPC), strikes and other exceptional occurrences (Rule 85(4) EPC).

If the application claiming priority is received late, it may be deemed received in time if the conditions of Rule 84a EPC are met, or if the cause of the delay qualifies under Rule 85(5) EPC.

There is no provision in the EPC for extension of the priority period. Further processing (Art. 121 EPC) or extension (Rule 84 EPC) is not possible, as this period is not an Office time limit but fixed in the Convention. Restitutio is not applicable (Art. 122(5) EPC).

The first application

The application whose priority is claimed must be the first application in or for that State to disclose the subject matter in question (Art. 87(1) EPC). If there are two applications disclosing the same subject matter, priority from the second application may only be claimed if the first application has been withdrawn, abandoned or refused on the date the second application was filed. The first application may not have been open to public inspection or have left any rights outstanding. The first application may never have served and may not thereafter serve as a basis for claiming a right of priority (Art. 87(4) EPC).

The first application must have been filed by the same applicant (inventors irrelevant) as the second application (J 11/95, Guidelines A-III 6.1 and C-V 2.6.2).

A European divisional application can never be the first application for any matter in its parent application. The parent application must be alive on the day the divisional is filed (Art. 76(3) and Rule 25(1) EPC). The same applies to a US Continuation-in-part (CIP), although a CIP may have added matter and a European divisional may not. For added matter the CIP can be the first application.

EPO does not investigate whether a (withdrawn or abandoned) first application exists, but considers Art. 87(4) EPC if evidence presents itself (Guidelines C-V 1.4a). For example, when the European application claims priority of a US CIP, or when the national patent office in question has published it on its list of "Applications withdrawn" (as the UK Patent Office does). The burden of proof that it was withdrawn in time is with the applicant (T 1056/01). Failure to prove means the first application is deemed to have been "alive" at the filing date of the second application. The priority claim from the second application is then invalid (T 1056/01).

Limiting the claims of the second application by disclaiming part of the first application does not make it the "first" (T 255/91).

Formalities for claiming priority

To gain the benefit of priority, the applicant must file a declaration of priority, a copy of the earlier application and a translation into English, French or German if the earlier application is not in one of these langagues (Art. 88(1) EPC).

Declaration of priority

Elements of the declaration

The declaration of priority shall state the date of the previous filing and the State in or for which it was made and shall indicate the file number (Art. 88(1), Rule 38(1) EPC). The date and State of the previous filing must be stated on filing the European patent application (Rule 38(2), Rule 26(2)(g) EPC). The file number shall be indicated before the end of the sixteenth month after the date of priority (Rule 38(2) EPC).

No declaration is necessary for divisional applications if the parent application claimed the same priority and that claim has not lapsed (Guidelines A-IV 1.2.3).

Correction of date and State of earlier application

No invitation to correct under Rule 41(1) EPC is sent if there is a defect in date or State (Rule 41(2) EPC).

A correction under Rule 88 EPC is possible only if made sufficiently early for a warning to be included in the publication of the application (J 6/91, Guidelines A-III 6.5).

When the date of the earlier application precedes the filing date by more than a year, applicant gets one month to indicate a corrected date (Rule 41(3) EPC).

Correction of file number

If examination by the Receiving Section (Art. 91(1)(d) EPC) reveals any defects in the file number, the applicant is invited (Art. 91(2), Rule 41(1) EPC) to correct.

A wrong file number may be corrected (Rule 88 EPC) at any time, even after publication, if the priority document is in the file. This way the public is not adversely affected (J 3/91).

Copy of the earlier application

A certified exact copy of the earlier application, accompanied by a certificate stating the date of filing, must be filed before the end of the sixteenth month after the date of priority (Art. 88(1), Rule 38(3) EPC).

When no copy is necessary

The EPO includes (free of charge) a copy of the previous application, from which priority is claimed, in the file of the European patent application, if the previous application is (Rule 38(4) EPC, OJ EPO 1999, 80):

  1. a European patent application;
  2. an international application filed with the European Patent Office as receiving Office under the Patent Cooperation Treaty;
  3. a Japanese patent or utility model application; or
  4. an international application filed with the Japanese Patent Office as receiving Office under the Patent Cooperation Treaty.

It is also not necessary to file a copy of the earlier application for a divisional application, if the parent application claimed the same priority, and to new applications filed under Art. 61(1)(b) EPC (Guidelines A-IV 1.2.3, Legal Advice 19/99).

Correction of missing priority document

If not filed in time, the deficiency is noted by the Receiving Section (Art. 91(1)(d) EPC) and the applicant is invited to correct (Art. 91(2), Rule 41(1) EPC). The deficiency only arises at the end of the sixteenth month (J 1/80).

The only remedy is restitutio (Art. 122 EPC). Further processing (Art. 121 EPC) is excluded as only priority is lost, not the whole application (Art. 91(3) EPC). Extension of the office time limit of Rule 41(1) EPC may be possible if requested in time (Rule 84 EPC).

Translation of the earlier application

If the earlier application is in a language other than English, French or German, a translation into one of these languages must be filed (Art. 88(1), Rule 38(5) EPC). The translation of the earlier application must be filed within a time limit to be set by the European Patent Office, which normally is only done if prior art was published or filed in the priority interval (Guidelines C-V 3.2). At the latest it must be filed within the time limit under Rule 51, paragraph 4 (Rule 38(5) EPC). The EPO may require the filing of a certificate that the translation corresponds to the original text (Rule 5 EPC).

When the EPO supplies a copy of the earlier application under Rule 38(4), it is still necessary to file a translation (LA 19/99 fn. 3, and reminder in OJ 2002, 192).

Declaration instead of translation

Instead of a translation, a declaration that the earlier application is identical to the European application claiming priority can be filed (Rule 38(5) EPC). A merely different arrangement of the various elements (i.e. the claims vs. the description) of the application does not affect the validity of such a declaration, but having more or less text does (Guidelines A-III 6.8, Legal Advice 19/99).

When it is not necessary to file a translation

If a translation is available to the EPO it will be added by the EPO, as Rule 38(4) applies mutatis mutandis (Rule 38(5) last sentence, see Guidelines A-IV 1.2.3).

It is also not necessary to file a translation of the earlier application for a divisional application or for new applications filed under Art. 61(1)(b) EPC, if the older application claimed the same priority (Guidelines A-IV 1.2.3, Legal Advice 19/99).

Correction of omitted translation

If no translation or declaration have been submitted in time under Rule 38(5) EPC, a deficiency under Art. 91(1)(d) EPC is noted by the Receiving Section. An invitation under Rule 41(1) EPC will be sent to invite correction. No correction means loss of priority (Art. 91(3) EPC).

If translation/declaration was filed in time, ask decision under Rule 69(2) EPC to prove. Otherwise restitutio (Art. 122 EPC) is possible. Further processing (Art. 121 EPC) is excluded as only priority is lost, not the whole application (Art. 91(3) EPC).

Adding an omitted priority claim

Adding a priority claim under Rule 88 EPC is possible, as the omission of a priority claim is nearly always a mistake and no proof is necessary (J 9/91). The request for correction must be made sufficiently early for a warning to be included in the publication of the application (J 6/91). After publication only possible if the mistake is immediately apparent (J 6/91).

Examination of validity of priority claim

The validity of a priority claim is normally not checked by the EPO, unless documents published in the priority year or prior rights filed in the priority year are are found (Guidelines C-VI 8.4-8.11).

Priority problems in practice

The question on how to determine whether a claim has the benefit of priority has been settled by the Enlarged Board of Appeals in G 2/98. The basic test to determine whether a claim is entitled to the date of a priority document is the same as the test of whether an amendment to an application satisfies the requirement of Art. 123(2) EPC. A priority claim is valid if the subject-matter of the claim can be derived directly and unambiguously from the disclosure of the invention in the priority document, when account is taken of any features implicit to a person skilled in the art in what is expressly mentioned in the document (Guidelines C-V 2.4).

Some problematic situations

Disclosure of combinations

A priority document may disclose different elements or embodiments, but fail to disclose their combination. A claim to the combination ("AND" claim) then does not have the benefit of priority (G 2/98 reason 6.6). An "OR" claim has two priorities (G 2/98 reason 6.7).

Selection from a range in the priority document

The priority document may disclose a range, for example "32 to 100 degrees Celsius". This does not implicitly disclose specific selections in the range, although the endpoints are disclosed (Guidelines C-IV 7.4). So only claims with the range or the endpoints would have priority.

Species and genus

A priority document may disclose a generic concept ("genus") and a later claim may claim a specific instance of that genus ("species"). Such a claim cannot have the benefit of priority, as a generic disclosure does not take away the novelty of specific instances (Guidelines C-IV 7.4). As the species thus is new, it clearly cannot be derived from the disclosure of the generic concept.

Similarly, the priority document may disclose a species and a later claim may claim the corresponding genus. Such a claim may have the benefit of priority, if the genus is implied by the species or how it is used. For example, the priority document may disclose a rubber element. If that element was used for its elasticity, then the priority document implicitly discloses "an elastic element".

Dependent claims

A dependent claim may have the priority date as effective date while its parent does not, or vice versa. For example, if the priority document discloses a species, a broad claim to the genus encompassing that species does not have the benefit of priority. A dependent claim to that particular species does have priority, though.

A dependent claim may refer back to multiple other claims. In that case it may have multiple effective dates. If claim 3 refers to "claim 1 or 2", and these claims have different effective dates, then claim 3 may have two effective dates.

Appendix: Some potential priority problems

Assume a priority document discloses and claims the construction of a new type of lamp. A year later, a new application is filed claiming priority of this document. All formalities have been met. The new application has the same disclosure and claims regarding the new lamp as the priority document. As a result, these claims have the benefit of the priority date.

The new application also claims various uses of the lamp. Unfortunately these were not all literally disclosed in the priority document. As a result some of these claims will not have the priority date as effective date.

Here are a few examples:

ClaimBasis in priority documentBenefit of priority?

A bicycle comprising the lamp of claim 1.

"This lamp can be used in vehicles such as bicycles."

Yes. The combination of lamp and bicycle is literally mentioned.

A bicycle comprising the lamp of claim 1, said lamp being powered by a dynamo.

"This lamp can be used in vehicles such as bicycles. Of course this requires a power source in or on the vehicle."

No. Although lamp and bicycle are mentioned, the dynamo is not. A "power source" can mean a lot of things (e.g. a battery) and so "dynamo" cannot be derived directly from the application.

A bicycle comprising the lamp of claim 1 releasably fastened to the bicycle.

"This lamp can be installed on vehicles such as bicycles, for example using nuts and bolts to mount the lamp on the bicycle."

Yes. The combination of lamp and bicycle is literally mentioned. The feature of "nuts and bolts" implicitly discloses "releasably fastened".

A bicycle comprising the lamp of claim 1, said lamp being connected to a dynamo as power source.

"This lamp can be used in vehicles such as bicycles. In bicycles the lamp could then be powered by the dynamo."

Yes. Bicycle, lamp and dynamo are mentioned in combination. From "be powered by the dynamo" the skilled person would immediately derive that lamp and dynamo are connected.

A vehicle comprising the lamp of claim 1.

"This lamp can be used in vehicles such as bicycles."

Yes. The combination of lamp and vehicle is literally mentioned.

A motorcycle comprising the lamp of claim 1.

"This lamp can be used in vehicles such as bicycles."

No. Although a motorcyle obviously is a "vehicle such as a bicycle", this information does not flow directly and unambigously from the quoted sentence.

A lighting arrangement comprising three lamps according to claim 1.

"A plurality of lamps can be installed in a device such as a flashlight to increase light output."

No. The sentence does not directly and unambigously disclose three lamps specifically.

A lighting arrangement comprising three lamps according to claim 1.

"A plurality of lamps can be installed in a device such as a flashlight to increase light output. A preferred embodiment has the lamps in a triangular arrangement."

Yes. A "triangular arrangement" directly discloses three lamps.

No. While a triangular arrangement directly suggests three lamps, this does not mean that three lamps in other arrangements are also disclosed. Hence this claim may not omit this feature.

The lamp of claim 1, being coupled to an on/off-switch.

"When the lamp is powered on, ..."

Yes. The term "powered on" implies the presence of an on/off-switch.

No. "Powering on" can also be done by plugging in the power cord.