What is a filing date?
Provisional Applications for Patent were created to allow inventors to establish earlier filing dates for subsequently-filed corresponding Non-Provisional Patent Applications. If a patent is later granted, the inventor will have established this early filing date and can use it as proof of the date on which his or her patent protection began, effectively receiving a total of 21 years protection for the invention.
Inventors should also make a note of the date on which their Non-Provisional Patent Application is published. Once an application is published, an applicant gains certain rights against infringers, since the publication gives notice to third parties that an application is under review. If a patent is granted, the inventor may seek royalty payments from any person who made or used the invention while the application was pending.