Are provisional patent applications public or are they kept confidential?
All patent applications received at the US Patent Office are kept secret by the Patent Office. The most commonly occurring exception to this rule is that when a patent issues, the application file becomes public. (Note that the entire application file becomes public, not just the issued patent itself.) Another exception is that if a patent application is referred to by number in an issued patent, the application file becomes public. This is the case for both provisional applications and regular applications under 37 CFR ยง 111(a). It has been proposed that the US Patent Office would change its rules on secrecy to be more like the rest of the world. In most countries other than the US, a patent application becomes public 18 months after the priority date.
