A United States patent protects your invention in this country only. If you want foreign patent protection, you may have to file in foreign countries. Normally, you would need a license from the Commissioner of Patents and Trademarks to file for a patent in another country within six months of filing in the United States. You should discuss the need for and advisability of filing in a foreign country with an patent attorney before doing so, as you may lose certain protections. Many foreign countries make all patent applications public upon filing, which may have some negative impacts in the United States.
Under treaties with most foreign countries, if you have filed a patent application in the U.S., it's possible to delay filing your application for a foreign patent for up to one year after the U.S. filing and still claim "priority" in the foreign country. Under the Patent Cooperation Treaty, many countries have actually combined and streamlined their processes. In Europe, for instance, you file a single application and submit it to the European Patent Office that then processes and sends out individual applications to all requested countries with each country’s individual requirements.
Also, the U.S. currently has two pilot work-share programs including the “New Route” and the “Triway.” The New Route allows a filer’s application to be accepted by both the United States Patent Office and the Japan Patent Office simultaneously, allowing protection in both countries. The Triway goes one step further and adds the European Patent Office to the application process as well. These programs are only in their test phase at this point, but may be worth taking advantage of.
One of the greatest hurdles for people seeking foreign patents will be the language, culture, and legal barriers. This is where selecting the best patent attorney comes into play. Ideally, you may be able to find a bi-cultural attorney in the U.S. who is familiar with the other countries that you are seeking patents with, but this is not guaranteed. Typically, the way that most inventors handle their foreign patenting needs is by hiring a patent attorney in the U.S. and then that patent attorney has established connections with another attorney in the country where you are seeking a patent. It's this hurdle, and the attorney’s fees that stem from it, that typically limit most private inventors to only one or two foreign countries for patents.