The DDP was created in 1969 to give inventors the option of submitting evidence of an invention's conception beyond the somewhat questionable practice of the "self addressed envelope." At this time, commercial services for individual inventors were not as widespread as they are now.
Records filed through the DDP can still provide a timeline evidence of conception. In the event of a dispute, an inventor may still be required to offer additional proof of exactly when the invention was reduced to practice. A non-expired provisional application filing date would be accepted by the Patent Office as a date of invention without the need for additional such evidence.
In comparison to the DDP filings, a provisional application allows the inventor to:
- Claim the provisional application's priority filing date in a non-provisional patent application submitted within one year.
- Claim "patent pending" status during the provisional application's duration.
- Forego building and testing a prototype.
- Forego the need to demonstrate the invention to witnesses and have them attest to this.
- Establish a U.S. filing date for foreign applicants.
- File for patent protection in foreign countries which have an "absolute novelty" rule. This bars anyone from obtaining a patent on an invention that has been disclosed in any way before a patent application has been filed.
