A prototype is not required to obtain a U.S. patent. However, assuming the prototype is kept confidential, and there is no offer for sale, sale, public use, commercial use, or other problematic activity, prior to filing a complete and timely patent application, it may be helpful for various reasons for a prototype to be prepared. Generally, an inventor may have a 1 year grace period from their own first disclosure to file a U.S. patent application, but many foreign countries may not provide any grace period for foreign patents, so keeping an invention and prototype confidential prior to filing is important to attempt to preserve any possible patent rights.
One of the reasons for preparing a prototype is that although an invention needs to be described in writing and generally with drawings in a patent application, some inventors may have difficulty completely describing all the details of the structure and operation of their invention or of preparing drawings needed for filing.
However, depending on the complexity of the invention, the inventor may be able to prepare at least a crude prototype. If the inventor provides a prototype it may help a registered patent attorney to have a better understanding of how the invention works, and to prepare a complete patent application that has a better chance of being allowed, and may result in an issued patent which provides stronger protection.
In addition, it is also possible that a prototype may make it easier to prepare both a design patent application and a utility patent application. Generally, a design patent relates to appearance and a utility patent relates to function. A physical prototype may have appearance aspects that can be protected by a design patent and functional aspects that can be protected by a utility patent.
A prototype may be especially helpful for a design patent application. Design patent application drawings generally need to include multiple views which are consistent; and need to comply with precise standards specified by the USPTO. Having an actual prototype helps a patent draftsperson to prepare accurate design patent drawings as required.