Novelty and prior art. Sometimes, two companies make the same invention around the same time. The inventor who files the patent application first will be granted the patent. Accordingly, in the investigation of the ‘novelty’ of the invention, the date of filing is determinative. In order to be considered new, nobody may have published about the invention (taken in its entirety, with all elements of the invention together in the publication) or otherwise made it available to the public. When assessing “prior art” a global approach is taken: if an inventor elsewhere in the world was first, that preceding invention determines state of the art.
A common (but expensive) mistake is if the inventor proclaims the invention in newspapers or on internet before filing for patent protection. Disclosures made to third persons or external organisations only safeguard patent protection if each person or organisation signs a (if only retroactively effective) non-disclosure agreement.
Priority year (grace period). In view of the prior art criterion, if someone files an application in a country which is party to the Paris Convention for the protection of industrial property, the applicant has six or twelve months after the first application to file for a patent in another State party as well. Publications about the invention or a sale or transfer of the patentable invention during those six or twelve months will be disregarded when determining whether an invention is new and involves an inventive step. This ‘grace period’ (or ‘priority year’) implies a right of priority over technological developments that take place in that period. Many patent offices publish the application 18 months after the priority date or filing date (the actual patent grant may take much more time).
Duration of patent examination. An inventor normally selects a few jurisdictions to file a patent application. Usually, these are large jurisdictions in which the impact of the patent will be considerable (e.g. the US, the UK, Germany, France, China, Japan) or jurisdictions in which the judicial patent system operates efficiently and professionally (e.g. the Netherlands, Chinese Taipei). After filing a patent, a national or supranational agency examines whether the invention is new, involves an inventive step and is of industrial utility. If the examiner has any doubts, the institute will issue an ‘office action’ after which the applicant may further substantiate, withdraw, abandon, modify or pursue the patent claims. In many cases, the office action leads to narrowing down the scope of the claimed invention. Also, third persons (such as competitors) may oppose the patentability. Usually such doubts are decided in the applicant’s favour because a final and less-abstract judgment on the validity or scope of a patent is possible in court (whilst the alternative, rejection of the patent, precludes all protection).
The application and examination procedure takes several years. Depending on the jurisdiction and the technical discipline involved (e.g. chemistry, biotech, pharma, electronics), a final decision may take three to five years, or much longer. Once the registration is complete, the patent protection has retroactive effect from the date of filing.
Duration. A registered patent typically lasts 20 years after the date of filing the application. The owner of the patent may prohibit others to use the patented invention in any product or to use the patented process. Extension of the duration of the patent is not possible. However, in relation to pharmaceutical patents, where clinical trials impose a further limitation of the effective duration of a patent, some countries permit a limited extension or a certain period or exclusive commercialisation of the patent.
Prior use defence. If an invention was patented by one company but already invented and used by another, most jurisdictions permit the defence of ‘prior use’ against a claim of infringement by the patent owner. Prior use is exempted from patent infringement claims if the alleged infringer can clearly and convincingly prove that it used the patented invention in a commercial setting. Obviously, the date of such prior use must precede both the patent filing and the publication. Understandably, such a ‘grandfather right’ does not apply if the former invention had been derived from the subsequent inventor. In order to prevent circumvention (or parallel trade), a prior user’s right is limited in scope and transferability.
Co-inventorship. A risk associated with patents is that a third party involved in the research or development work leading to the patent, may claim co-inventorship. For example, a customer or manufacturer of a research-focused supplier-inventor who was invited (a) to testing the invention, and (b) to assist in improving certain practical aspects of the invention. The customer or manufacturer might claim that it made a substantial contribution to the invention, which could result in co-ownership. Often, the customer or manufacturer is granted another benefit for its assistance, such as exclusive distribution or manufacturing rights during a certain period of time.
 Including the US since the Leahy-Smith America Invents Act 2011 (AIA) of 16 March 2013. As of that date, the first-to-invent system was replaced by the first-to-file system, which has been adopted everywhere in the world.
 In the EU, whilst the technical examination (of novelty and inventiveness) is conducted by a pan-European institute, a ‘European patent’ does not exist yet. After determination as to whether an invention is patentable, the applicant must choose in which EU member states it wishes to obtain patent registration (and in order to achieve this, certified translations of the selected member states must be prepared). European patents are therefore national patents.
 In the US AIA (2013), the scope of excusable prior use defence is more extensive. The patented invention has to have been used at least within one year prior to the earliest effective date.