Given the purpose and special nature of the opposition procedure, patent proprietors may not oppose their own patent. In G 9/93 (OJ 1994, 891), the Enlarged Board of Appeal departed from the view taken in G 1/84 (OJ 1985, 299) and held that patent proprietors were not covered by the expression "any person" used in Art. 99(1) EPC 1973. The provisions of Part V Opposition and limitation procedureof the EPC and the corresponding Implementing Regulations were clearly based on the assumption that the opponent was a person other than the patent proprietor and that the opposition proceedings were always inter partes. The case law established in the G 1/84 decision is thus obsolete.
In T 3/06 the patentee argued that opponent 2 as the inventor of the patent in suit could not validly file an opposition even if the plain language definition of "any person" in Art. 99(1) EPC did not prevent inventors from filing an opposition. The patentee suggested that the ruling in G 9/93 (OJ 1994, 891), which eliminated patent proprietors from the definition of "any person", should be updated to exclude, in the circumstances, the inventor also, as he was a shareholder of the patent proprietor. The board held the patent proprietor and the opposing inventor to be different persons. The inventor, although a shareholder in the patent proprietor, was not an executive of the company, nor did he have any substantial influence on commercial and judicial decisions concerning the business of the patent proprietor. In particular, the patent assignment contracts constituted evidence for the fact that this right lay exclusively with the patent proprietor.