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European IP Bulletin, Issue 29, February - Hot Topics

Hot Topics

1. Comparison: Divisional Patents in Europe and the United States

Patent applications may have offspring in the form of additional applications based on the main application, to cater for additional inventions that are disclosed in the main application. This stems from a basic requirement of ‘unity of invention’ that dictates that no more than one inventive concept may be covered by the claims of a single patent. Broadly speaking, the purposes of this rule are firstly practical in that only one invention can be protected per application fee, but secondly principled in that it creates certainty for the public. This second purpose arises as the public have a right to know the scope of protection of a patent. If a second invention could be found in the patent with the same priority date then there would be uncertainty as to which patents contained hidden or partially hidden inventions.

Typically, a division might occur after first examination where the Patent Office examiner identifies a second invention and requires the applicant to divide off this second invention. More controversially however, it is possible for the applicant himself to take the initiative and use the system for his own ends, one possible goal being an attempt to protect an improvement of the invention. These latter cases serve to contrast the practices allowed either side of the Atlantic.

In the US, a division called a ‘continuation’ is permitted. Under the European Patent Court, the system uses the term ‘divisional application’. In both cases, the divided application is based on the same disclosure as the parent application. If a subsequent division is made  then the first ‘offspring’ application then the initial application will be described as the ‘grandparent’ application and so on.

As well as sharing the disclosure of the parent application, the divisional application will make a claim to the priority date of the parent. This is obviously an advantage where technology the interval between filing of the parent and offspring might give rise to novelty/inventive step destroying publications.

In the US a number of conditions exist to support the claim to the same priority:

• The parent application must still be pending, however, the grandparent need not be pending;
• There must be at least one named inventor in common between the parent and offspring. Thus, an inventor can be common between the offspring and either parent or grandparent application so long as the grandparent is still pending. If the grandparent is no longer pending, then the common inventor must be in the parent application;
• The claims in the offspring must be fully supported by the disclosure in the parent application. Typically, the continuation is filed with the same disclosure as in the parent so in normal continuations this is not a problem.

Similar rules have been considered by the European Patent Office (EPO) in cases on divisional applications:

• Case J 7/04 confirmed that the last possible date on which a divisional may be filed is the day before the date of grant of the parent. Case T1158/01 confirmed, following clarification of the drafting of the European Patent Convention (EPC) and especially of the French text at the inter-governmental conference on the EPC in 2000, that multiple divisional applications are allowed by the EPC.
• Case J 2/01 (Legal Board of Appeal) confirmed that the identity of the divisional applicant(s) must be the same as the applicant or co-applicants named at the time on the application form from which the divisional is filed.

To this extent, the European approach is similar to the US, and in practice an identical disclosure is filed with the offspring and then reduced to support the carved out claims made in the offspring.

However, the US system of continuations permits a US applicant to make sure that the disclosure of an original patent application is always pending. Since an unlimited number of continuation applications may be filed (the only requirement being that at least one application in the chain of continuation applications is still pending) it is possible to keep a chain of patent applications alive for a long period of time.

This is useful when a technology field is crowded and there are several competitors, and when it is not certain exactly what the competitor will try to bring to market. Competitors will often attempt to design around patent claims. In this case, the initial claims of the original patent may not be effective in maintaining the monopoly power of the patentee. By filing additional continuation applications whenever an existing patent application is to issue as a patent or whenever the prosecution of an existing patent application is to be terminated, an applicant can make sure that a continuation patent application claiming priority from the original application is always pending. Then, if a competing product is ever produced, the claims of the pending continuation application can be amended, or another continuation application can be filed, so that the claims clearly cover the competing product, ensuring that the product will infringe the new claims.

This approach has been frowned upon in Europe and shows in some of the decisions mentioned above.

Indeed, the EPO now requires that the grandparent still be pending when a second divisional is filed if inventions from that grandparent are to be contained in the second divisional. In Case T720/02, the tribunal said: “To allow subject matter from a grandparent application (which was no longer pending) which was reproduced in the description of a parent divisional application but not encompassed by the invention actually divided out of the grandparent application to be further divided out of that parent application at a later date would be to allow applicants by the mere filing of recurrent cascading divisional applications to leave the public completely uncertain during most of the life of a patent as to how much of the subject matter of the original patent application might still be claimed”.

The contrasting nature between the US and European approaches is further demonstrated when considering a further US form of division called a ‘continuation-in-part’ (“CIP”). These allow for inclusion of the same disclosure that is found in a parent application plus some additional invention disclosure, for example to support an improvement. Multiple priority dates can arise where some of the claims of the CIP are supported by the parent application but other claims are supported by new matter introduced to the offspring application.

In contrast, under Art 76(1) of the EPC if the divisional includes added new matter then the divisional will be invalid. This cannot only invalidate the first divisional but subsequent divisional applications (Case T1158/01). Furthermore, claims in the offspring will be restricted by those inventions or group of inventions claimed in the parent. Further offspring will likewise be restricted. This leaves no room for claiming improvements in divisional applications under the EPC (Case T720/02). This approach is supported by the requirement under the EPC that the identity of the divisional applicant(s) must be the same as the applicant or co-applicants named at the time on the application form from which the divisional is filed not just that there is one common inventor as in the US (Case J 2/01).

A few years ago, Edmund Kitch a US economist published a paper to justify the patent system, describing it a tool for ‘prospecting’ (or fishing!) just as prospectors in the old Wild West were given prospecting rights. US continuation applications do partly reflect this nature, allowing patentees to look again at the claims made and to extend the scope of their protection gradually at a later date. However, the EPO Boards of Appeal have made a clear policy statement in their decisions that the patent system in Europe must provide certainty for the public. This balances the right of third parties to design around the patent claims as originally filed and the right of patentees to obtain protection fairly based on the invention they have claimed at the original date of filing. The contrasting views from either side of the Atlantic on dividing out patent applications does give rise to important considerations when drafting patent applications, as well as for ongoing prosecution of current applications.

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