Can patents ever infringe other patents?
Recently talking to a client, she told me that she was worried that her company’s new patent application infringing another patent. The European Patent Office had recently issued a search report and one of the older patent applications mentioned in the report was indicated as being highly relevant to her invention. I pointed out that the cited patent application was only an application – it had not yet been granted or approved by the patent examiner. A quick check of the European Patent Office’s register showed, in fact, that the older patent application was no longer in force, at least in Europe, as the applicant had no longer paid the annual renewal fees. Our client was relieved. No worries.
It set me thinking about the question of can a patent ever actually infringe another patent. The European Patent Convention is clear: only products, methods, and uses can infringe the claims of a granted European patent (in the US the definition is slightly different – machines, articles of manufacture, composition of matter or processes will infringe a patent). That quickly settled it – there was no infringement. Firstly, it is only the claims that are relevant for determining infringement and, secondly, a description of an invention in a patent document can never “infringe”, since the description does not fall under the definition of what can infringe.
On the other hand, it is possible that a product sold by the client and using the technology described (and later patented) in the client’s patent could indeed also infringe another, older granted patent. That’s not uncommon. The grant of a patent does not give the holder the right to use or work the invention – it only gives the right to stop someone else from using the invention without a licence to the patent. It is indeed possible for two patent holders to block each other – both have patents covering parts of the technology and neither can sell their own products without a licence from the other patent holder.
So, the answer to the question in the title is clearly NO – a patent can never infringe another patent. But a product produced using the invention described in the client’s patent could infringe a patent held by another company and which is why a patent search is usefully carried out before releasing a product.