The outcome of disclosing an invention depends on two main factors: when you disclose it and how you disclose it.
The first requirement for a potential invention to be patentable is that the invention is new, or ‘novel’, at the time the patent application is filed. Any and all information in the public domain is relevant to this requirement and if the invention is described in any publicly available format anywhere in the world, it’s not novel and can’t be patented.
If you disclose your invention (with details of how it’s made, carried out, or how it works) then that knowledge is deemed to be in the public domain. It becomes part of the ‘prior art’. A patent application filed for the invention after such disclosure is, therefore, almost certain to fail on the basis that it is not novel over the prior art (this will depend on whether the disclosure counts as an ‘enabling one’ — see below).
The way to avoid this problem seems to be to file a patent application as soon as possible before discussing the invention with anybody else. However, it must be borne in mind that no information may be added to a patent application once it has been filed, so it’s important that the application contains as much relevant information about the invention as possible at the time of filing.
If you’re considering licensing your invention, you must not rely on a non-disclosure agreement to protect the novelty of your invention should it be revealed before you file a patent application. It’s a good idea to discuss these issues with a patent attorney before disclosing your invention to possible business partners.
For a disclosure to be novelty-destroying, it must contain enough detail to allow a reasonably skilled person to put the invention into effect — this is referred to as ‘enabling disclosure’.
For example, if your invention is wholly contained within an opaque box having an input socket and an output socket, and you demonstrate the box accepting an input signal and providing an output signal, then you have not necessarily disclosed how the invention actually works — you may not have provided an enabling disclosure. Therefore, a subsequently filed patent application covering the contents of the box may still be successful.
Be aware that a disclosure does not have to be written down for it to count as novelty-destroying. Continuing the opaque box example: an oral disclosure, such as a short, verbal explanation of the box’s internal components, might well be enough to place the invention in the public domain and thus to form part of the prior art.