1. The legal provisions

The requirement for unity of invention is set forth in Article 82 of the European Patent Convention (EPC) :
"The European patent application shall relate to one invention only or to a group of inventions so linked as to form a single general inventive concept."

As to the grounds for such a provision, some decisions of Boards of Appeal (such as T 110/82, OJ 1983, 274) refer to the regulatory function of Article 82 EPC, namely :

• to prevent unjustified savings in the payment of official fees,
  
  
• to provide for a "ready comprehensibility" of the object for which protection is sought.

Ready comprehensibility of what is claimed is a legitimate reason. Problem is that it is often hardly achieved, even when unity of invention is not questionable. It is nevertheless a good reason to be put forward, in order that the requirement for unity of invention does not appear to be dictated only for the sake of a wealthy EPO budget.

Single inventive concept is defined in Rule 30(1) EPC :
"Where a group of inventions is claimed in one and the same European patent application, the requirement of unity of invention referred to in Article 82 shall be fulfilled only when there is a technical relationship among those inventions involving one or more of the same or corresponding special technical features. The expression "special technical features" shall means those features which define a contribution which each of the claimed inventions considered as a whole makes over the prior art"

As will be seen hereinafter, assessment of unity of invention by the EPO focused on the identification of such special technical features commonly shared by the different claimed objects.

Those technical features qualify as special in the sense that they define a contribution over the prior art, such a contribution being required to recognise a common inventive concept.

The above applies equally for European patent applications and for PCT applications. Indeed, same wording as in Article 82 and Rule 30(1) of the EPC is used in Rules 13.1 and 13.2 of the PCT.

2. Assessment of Unity of Invention

2.1 Way of claiming

Although unity of invention is not affected by the way of claiming, the EPO has developed guidelines as to the allowability of different independent claims in a single application. This applies both to European patent applications and to PCT applications for which the EPO acts as International Searching Authority (ISA).

A single inventive concept may be recognised between independent claims of different categories as in the following examples :

1. a claim for a product, a claim for a process specially adapted for the manufacture of the product and a claim for a use of the product;
   
   
2. a claim for a process and a claim for an apparatus or means specifically designed for carrying out the process;
   
   
3. a claim for a product, a claim for a process specially adapted for the manufacture of the product and a claim for an apparatus or means specifically designed for carrying out the process.

Possibilities (a), (b) and (c) were expressly mentioned in the original version of Rule 30 EPC, whereas possibilities (a) and (b) were expressly mentioned in the original version of Rule 13 PCT.

Unity between product and process claims requires that the process inherently results in the product, or at least in a component of a composition claimed (decision T 492/91).

Unity between process and apparatus or means requires that the apparatus or means have been specifically designed for carrying the process, or at least a step of the process (T 861/92), but without excluding any other possible use (W 32/88 and W 16/89).

A single inventive concept may also be recognised between independent claims of same category.

This is however limited to specific cases, such as :

• several uses of a same product : a pharmaceutical use and a non-therapeutic use (T 200/86), a first medical use and a second medical use (W 5/91, W 28/91), ...
  
  
• intermediate product(s) and final product deriving therefrom, provided they share a same essential structural element (T /82, T 110/82, T 35/87, T 470/91).

Indeed, the EPO is not likely to accept a plurality of independent claims having substantially the same object, as can be found in US-type patent applications The objection would then be based on Article 84 EPC (lack of clarity and conciseness).

2.2 Identification of common special features

The EPO has taken the following position. The requirement of special technical features defining a contribution over the prior art means that those technical features must be new and not obvious to support a common inventive concept.

This allows assessment of unity of invention to be made a posteriori, i.e. after comparison of the claims with the prior art.

With respect to PCT applications for which the EPO acts as ISA, this has been confirmed by a decision of the Enlarged Board of Appeals (G 1/89, G 2/89).

Since then, there are a number of decisions by EPO Boards of Appeal holding that there is no unity of invention when no common new and not obvious feature(s) can be recognised in the part of different claims distinguishing over the closest prior art.

This means that the assessment of unity of invention is made not with respect of the general inventive concept subjectively claimed by the Applicant, but with respect to the remaining inventive features after comparison with the prior art uncovered during the search. This means also that, at the search stage, some substantive examination as to the novelty and non-obviousness is carried out, although the lack of novelty and non-obviousness should be "immediately" apparent (W 24/90) to validly support an objection of lack of unity.

3. Non-unity objections

3.1 European Patent Applications

When the Examiner considers there is no unity of invention, he draws up a partial search report relative to the claims directed to the first identified invention (including claim 1) and issues an invitation to pay further search fee(s) for the other identified invention(s).

If the Applicant decides not to pay further search fee(s), the application will proceed only with respect to the searched subject matter (decision G 2/92) of the Enlarged Board of Appeals). Protection on the other subject matter(s) can be obtained only through filing of divisional application(s).

It is only when the Applicant pays further search fee(s) that he has the possibility to pursue the application with respect to any of the searched subject matters and to contest the objection of non-unity and request refund of the further search fees paid.

It is the Examining Division which is competent to decide on the issue of unity of invention. If it decides that the objection of non-unity was well-founded (and is eventually approved by the Board of Appeals), divisional application(s) will have to be filed if protection is sought on several subject matters. If it decides that the objection was not well founded, the further search fees paid will be reimbursed.

3.2 PCT applications

As for European patent applications, when the searching Examiner considers there is no unity of invention, he draws up a partial search report and invites to pay further search fee(s).

If the Applicant does not pay further search fee(s),the non-searched subject matter(s) cannot be subject of international preliminary examination.

If the Applicant wishes to contest the allegation of non-unity, he must pay the further search fee(s) under protest. The protest is examined by a three-member board (Notice from the EPO dated August 26, 1992). The decision of the board may be appealed under payment of a protest fee.

At the international preliminary examination stage, the issue of unity of invention may be taken again by the EPO acting as IPEA. If the Examiner considers there is no unity of invention, he issues an invitation to pay further preliminary examination fees.

Payment of those fees may be made under protest, as at the search stage.

4. Divisional Applications

The possibility of introducing amendments upon filing of a divisional application, with respect to the original parent application is ruled by Article 76(1) EPC. It is interpreted by the EPO in the same way as the possibility to introduce amendments in a pending application which is ruled by Article 123(2) EPC.

Therefore, when filing a divisional application :

• there is no possibility to add new matter : all the features of the divisional application must have been indicated in the original parent application, and
  
  
• moreover, the subject matter of the claims must be directly and unambiguously disclosed in the parent application (T 514/88).

Then, if you experience difficulties in amending the claims of a pending European application, in particular with a view to broaden or shift the scope of protection by deleting features which appeared originally in the main claim, filing of a divisional application will not help.

This may explain the lack of enthusiasm in filing divisional applications at the EPO. Although the number of divisionals filed each year increases, it remains below 3 % of the total number of applications filed as shown in the appended table.

5. Consequences in Practice

5.1 Lack of Flexibility

The EPO's practice lacks flexibility at different levels with the common consequence of introducing a cost barrier detrimental mainly to SMEs.

This can be illustrated by the following examples :

1. Assessment of unity of invention a posteriori.
   
   If it turns out that a claim generic to several embodiments of an invention does not appear to be new and non-obvious, no possibility is offered to keep all embodiments in a same application if they do not share common inventive features.
   The common link between the embodiments could be more generally seen in the problem to be solved with respect to the closest prior art.
   In many cases, the additional costs incurred for the filing, prosecuting and granting steps, for the national validations and for renewals are totally disproportional with the additional searching and examination efforts that would have been necessary.
   The fact that in some instances the costs for additional searching may be very low is even acknowledged by the EPO. Indeed, in a situation where the searching examiner identifies several different inventions, the EPO Guidelines encourage the Examiner to immediately achieve a search on the additional subject-matters, when this does not require important efforts, but to keep the results until the Applicant has paid further search fees!
   
   
2. Invitation to pay further search fees
   
   There is no possibility to challenge an objection of lack of unity of invention or to safeguard a future possibility to pursue the application on a different subject matter without immediately paying further search fees.
   Even if a refund of the additionally paid search fees may be obtained, the obligation to pay immediately often represents a high financial burden.
   
   
3. Scope of divisional applications
   
   The strict interpretation of Article 76(1) EPC considerably reduces the attractiveness of filing divisional applications.
   The EPO is far less flexible than other Patent Offices, even national Patent Offices in Europe, regarding the relationship between the object claimed in a divisional application and the initial content of the parent application.
   
   
4. New matter in divisional applications
   
   Proposals which have been made in the past to offer the possibility to introduce new matter in divisional applications have not received much support, in particular from the EPO.
   Indeed, this was seen as an importation into Europe of the US C-I-P application system. The US continuation application system has been much criticised in Europe.
   However, it may not have been realised that a system with new matter introduced into divisional applications would not show the alleged drawbacks of the US continuation system, as long as the divisional applications are published immediately.
   The matter is worth being revisited. The extent of opposability of the parent application, if published when the divisional application is filed, needs also to be carefully studied. Indeed, if the parent application were to form part of the prior art, no special interest can be found in filing a divisional application instead of a new application.
   
   

5.2 Lack of Harmonisation

At the Fourth International Symposium on Reduction of Patent Costs held last July in The Hague (Netherlands), Mr Kenzo Morita reported a case study made by the Japan Intellectual Property Association showing the diverging ways in which unity of invention was assessed for parallel patent applications filed at the USPTO, the JPO and the EPO.

This is even true in case of parallel applications deriving from a same PCT application, even though some PCT Rules apply, and despite the conclusion of an agreement between the USPTO, the JPO and the EPO in 1988 with a view to "harmonising unity of invention practice in the three Offices".

The EPO claims that its guidelines for assessing unity of invention between independent claims of different or same categories are directly based on that agreement.

From experience, one can deduct that either such an agreement is ignored by some Patent Offices, or leaves enough room for interpretation to continue to apply long-established practices.

Fighting against an Examiner to have correct standards for unity of invention applied costs money, in particular in the US.

Effective harmonisation and education of Examiners is needed to avoid not only procedural costs but also drafting difficulties.