Article 5

An invention shall be considered as involving an inventive step if it is not obvious having regard to the state of the art. However, for the purposes of considering whether or not an invention involves an inventive step, the law of any Contracting State may, either generally or in relation to particular classes of patents or patent applications, for example patents of addition, provide that the state of the art shall not include all or any of the patents or patent applications mentioned in paragraph 3 of Article 4.