Most countries have their own patenting entity with unique rules.
Patents are enforceable only in the country in which it is granted. U.S. patents protect you only inside the U.S. There is no such thing as a worldwide patent.
If you are interested in obtaining a granted patent in another country, you should consider filing with the Patent Cooperation Treaty (PCT) to facilitate your application filings in other countries.
Generally, the costs for filing an application outside the U.S. will be higher, potentially a lot higher.
Be very cautious about disclosing your idea to others. Some countries, especially the European Union, will not grant a patent if the application is filed after the date of public disclosure. Unlike the 12 month reprieve provided here in the U.S., you should discuss with your patent attorney or agent when and how to disclose your idea in the most appropriate manner for your situation.
Finally, you should consider investing additional money in market and patent analyses to better understand the risks and rewards of filing in other countries.
This does not mean you should not seek a foreign patent. Here’s an example to help clarify. X Inc. operates in the US and sells its main products to Brazil. X Inc. has two significant competitors. One is in the US and the other is in Germany. X Inc. has a new product that merits patent protection. Where should X Inc. file its applications?
In this example, several countries are worth discussion-
• To protect its basic rights, X Inc. should file in the US.
• To keep others from selling in its main market, X Inc. should consider filing in Brazil. A patent there will keep a manufacturer in China, or some other country, from making and exporting to Brazil similar products.
• To keep a limit on its main competition, X Inc. should consider filing in Germany. A patent there will prevent a known competitor from making products that infringe the products of X. Inc.
In short, think in terms of:
• Where you make your product• Where you sell your product
• Where known and unknown competitors might seek to perform an end-run around you.
This is simplistic, but it is a good starting point for this conversation.