Question: I have invented a product that serves a purpose. The purpose is unique. Can the purpose have patent protection?
A similar situation could be related to the use of traffic lights vs stop signs. The purpose is to project the same information but with different products. How can I protect the purpose of my invention that serves a useful unique and specific purpose with my product that has the sole intent to serve the purpose when someone else could perhaps create another product with the same purpose. This is a solution to a huge problem and I fear that once the solution is exposed then marketing of different products to accomplish the same purpose will pop up everywhere. Perhaps this is more of a marketing issue that a patent issue.
Answer: You will not be able to protect against the copying of a purpose. However, you can protect with a patent the specific way you accomplish your purpose, for example, controlling traffic with the use of a stop sign.