Only certain patent-related files are open to the public. The rest are kept under the lock and key of the Patent and Trademark Office.

Pending, non-published patent applications are not available to the public.

It may take years for an application to issue into a patent. Although the PTO will freely discuss and share the invention within its examination room walls, members of the public will not have access to the contents of the patent application until it is published. Not only is the general public prevented from accessing the contents, they can't even find out that the application exists.

But, there is a loop-hole.

Members of the public may be granted a request to view a particular pending application. There is some paperwork involved. The individual must send in a petition to the PTO stating reasons why they should be granted access to that particular application. A copy of this petition must then be serviced (given) to the patent applicant/owner. The major reason for servicing the applicant is to allow the applicant or owner of the patent the right to grant the petitioner access to only a portion of the application as opposed to the entire application.

There are times when a patent application contains material that is sensitive to national security. The PTO will not hesitate to place a secrecy order on these. Secrecy orders prevent anyone without top secret clearance from viewing the application, even after it is allowed to patent. Our government has the right to place a secrecy order on whatever they believe meets the criteria.

Issued patents not under secrecy order are always accessible to the public.