A patent lasts for a maximum of 20 years subject to the payment of annual renewal fees for the fifth and subsequent years.
A patent is legally enforceable to prevent others exploiting the invention protected by the patent (irrespective of whether there has been copying of the invention). It is a common misconception that ownership of a patent in respect of an invention entitles the owner to exploit the invention. It does not.
Most patents only protect improvements or developments of existing products or processes. This means that there can be prior patents or other protection for features of the existing products or processes used in the patented improvement or development. If such a prior patent or other protection is still in force, use of the improvement or development will infringe it. Nevertheless, this will not prevent the inventor obtaining a patent for the improvement or development. It does however mean that the agreement of the owner of the existing patent or other protection will be required to exploit the improvement or development, for example by the grant of a licence.
To be patentable, an invention must be new at the date of application for a patent. It is essential therefore that details of the invention are not disclosed before an application for a patent is filed. Moreover, the invention must involve an inventive step, that is to say it must not be an obvious development in the light of existing knowledge. Also the invention must be capable of industrial application and it must not fall within an expressly excluded group of ideas.
A patent can be infringed by doing a number of things. For example, a patent for a product is infringed by making, selling, using or importing the product, whilst a patent for a process is infringed by using the process and also by using or importing any product obtained directly by means of such process. It can also be an infringement in some circumstances to supply only part of a patented invention. To be an infringement, a product or process does not necessarily have to fall within the wording of the claims of the patent on a literal interpretation of their wording. This is because the claims in a patent may in some circumstances be interpreted more broadly, so that infringement can still be held to have taken place.
The remedies for infringement of a patent may include an injunction restraining the infringer from further acts of infringement, delivery up or destruction of infringing products, and/or the payment of damages in respect of past infringements.
Care must be exercised when threatening an infringer with legal proceedings, as there are some circumstances when the person threatened can sue the person making the threat for damages and other remedies.
