If a patent is to be considered valid, the claimed invention must be both new and inventive over the prior art. During the prosecution of a patent application, the prior art considered by the Examiner is usually confined to published documents, more specifically published patent documents and research papers. However, the complete body of prior art includes any public disclosure of the invention, whether written, oral, or based on prior use. Additionally, it is not necessary for a member of the public to actually read, see or hear a disclosure for it to be considered public. For example, the contents of a book placed in a library are publicly disclosed, even if the book remains unread.
The natural course of innovation means that many inventors develop prototypes of their invention before filing a patent application. Testing these prototypes is often essential in producing the final, commercial product. However, in terms of disclosure, it is critical that inventors keep these prototypes and tests confidential, typically behind closed doors.
Where inventors have tested their products in potentially public locations, the pre-eminent case law stems from Mishan v Hozelock. Here, the inventor had tested his new prototype hose in his front garden. In court, it was considered that there was no public disclosure of the prototype hose. The court reached this conclusion as the inventor gave evidence that he would have hidden the prototype from anyone passing by when the tests took place. As such, that person would not have been given access to any information relating to the prototype.
However, such arguments are not always persuasive. In a recent case, Claydon v Mzuri, similar arguments were presented. However, the court decided it was not, in effect, possible to hide the invention from a passer-by given it was attached to a tractor.
As such, it is clear that what amounts to a public disclosure by way of prior use relies heavily on the facts of the matter at hand. The intention for the inventor to keep the prototype hidden from public view is not always sufficient to prevent public disclosure. Therefore, this recent judgment highlights the need for inventors and applicants to ensure that patent applications are filed before any public disclosure of the invention, especially before any trials potentially accessible to the public.
