Generally speaking, limitation proceedings for granted patents would allow patentees to narrow the scope of protection conferred by a patent after grant (post-grant amendment) by means of a simple procedure. In practice, it may be necessary to narrow a scope of protection of a granted patent if, because of prior art which was not known during the examination proceedings or prior national rights not taken into account in these proceedings, the extent of the protection conferred is too broad. First, through the limitation procedure, patent owners may reduce the extent of the protection claimed in order to overcome certain invalidation claims over the validity of a patent. Further, post-grant limitation may clear certain legal uncertainties and therefore facilitates third parties’ access to the freely available prior art.

In Vietnam, the intellectual property law allows the patent’s owners to narrow the scope of protection of their patents. It is under the circumstance that the patent is partly invalidated by a third party during the protection term based on the ground that a part of protected invention(s) of the granted patent failed to meet patentable requirements at the granting date, then the patent’s owner wishes to narrow the scope of protection of the patent in order to maintain the validity of the remaining inventions of the patent. The problem is how can amend the patent’s specification to narrow the scope of protection according to the Vietnam intellectual property law and regulations.

Vietnam Intellectual Property Law No. 50/2005 (IP Law) generally stipulates that the patent owner has the right to request the state administrative authority of industrial property rights to narrow the scope of industrial property rights. Accordingly, it can be construed that the patent owner may make any amendment to the claims in order to narrow the scope of protection, for example, by adding additional feature(s) to a claim, adding a disclaimer to a claim, or removing one or more claims, either independent or dependent one(s) from the patent claim set, etc.

However, as stipulated in Circular 01/2007/BKHCN providing guidelines for implementing the provisions of the IP Law, it is understood that in order to narrow the scope of protection of a patent, the patent owner may remove one or more independent/dependent claim(s). It means that the patent owner cannot narrow the scope of protection of a patent by adding some additional feature(s) to a claim or by adding a disclaimer to a claim and so on.

Taking an example for the circumstance, assuming a patent was granted comprising claim 1 as “1. Apparatus, comprising components A, B and C.” After granting of the patent, a third party requested to invalidate the patent basing on the ground lacking of novelty/inventive step. In order to restore the novelty/inventive step of the patent, the patent owner had amended claim 1 by adding a disclaimer as “1. Apparatus, comprising components A, B and C, wherein narrow the scope of protection of a patent”. Such amendment is acceptable according to the Intellectual Property Law because the scope of protection of the patent shall be narrowed after having claim 1 amended in that manner. However, the amendment is not acceptable according to Circular 01 because the patent owner has amended claim 1 by adding an additional feature as “narrow the scope of protection of a patent” to claim 1, he/she has not removed the entire claim 1 as specifically required in Circular 01.

For similar limitation proceedings in the patent practice before the European Patent Office, making amendment by adding a disclaimer to a granted claim of the patent is allowable. More particularly, as stipulated in Regulations to European Patent Conventions, any amendment to the description, claims and drawings is allowable provided that the amendments are occasioned by a ground for opposition even if that ground has not been invoked by the opponent. Further, when examining a request for limitation, the EPO does not examine whether the subject-matter of the limited patent is still patentable, therefore a quick decision can be guaranteed.

In patent practice in Vietnam, there have not been any cases in which the patent was partly invalidated and then the patent owner requested to narrow the scope of protection of the patent so that it is hard to say what kinds of amendment of patent’s claims shall be accepted by the National Office of Intellectual Property of Vietnam in practice. It is not clear whether a request for limitation shall be subject to a reexamination procedure as well. We are now waiting for a particular case happening to have a clear answer for the question.