What is the difference in utility patent application vs provisional?

Yes - bit is very possible that it can be filed as what is known as an improvement patent over the first device. However i would have to know more of the details as to what the actual design changes and improvements were.

A provisional application protects the invention described therein for one year - then it expires. If no action is taken to convert the provisional application into a formal utility application before the provisional expires - there is no more patent protection available for that invention. This is especially true when there has been a public disclosure of the invention - since that creates "prior art" - and adds to the body of knowledge against which other inventions will be tested for (1) novelty, (2) utility and (3) non-obviousness - the three requirements for an invention to be patentable. Here, prototype #1 is prior art against which prototype #6 must be sufficiently different to be patentable. Novelty is easy if #6 is different from #1. Utility is easy if the prototype has a real world "use." The hurdle to overcome is the last requirement - is #6 sufficiently different from #1 that the changes would not have been "obvious" to persons having ordinary skill in this art - based on the knowledge of #1 and other known prior art. Big differences are often not obvious. Minor differences, giving the expected results, are often obvious. If prototype #6 is still secret - you can file an application. If #6 has been made public - the critical question is - when did this occur? A one-year grace period from public disclosure is still available in the US - but filing first is now required under US Patent Law for the best chance of obtaining a patent.

This is a great question and there is a lot of misinformation regarding what a provisional patent application is. The law regarding what a patent application needs to include are exactly the same for both a provisional and a utility application except; and of course this is a big except, that a provisional application does not have any claims. The claims of a patent application are the heart of the patent application and they are what actually protects your invention should you ever need to go to court. They define your invention. However, although the provisional application lacks claims, it must be able to support the claims that will appear in the full utility application. Unfortunately, as long as you pay the filing fee and call it a patent application, you will receive a very official looking filing receipt saying that you have a patent application and allow you to claim "patent pending" status. I say unfortunately, because if your provisional application does not support your future claims, you have no protection, and it is worse than not filing any application because you think you are protected. Of course, if your invention is not successful, none of this matters, but if you are successful and you bring an infringement lawsuit, the opposing side will have access to the provisional application and if they can show that your application was not enabling, your patent may be invalidated. I am all for provisional applications for the private inventor as they give you time to pursue your invention under the patent pending status while postponing some of the costs of trying to obtain patent protection, but you really have to have a very thorough provisional application in order to be protected. In the long run, it costs more to file a provisional application since you are not required to file provisionally, but it can delay some of the costs until you have a chance to test the market. As to the other part of your question, provisional applications by themselves are confidential and do not count as public disclosure. This is not the end of the analysis; you also have one year from the time of a public disclosure to file a patent application or you lose the right to file for the patent. The provisional application will not prevent you from filing for a patent application, but a public disclosure over a year will. If you needed the date of the provisional to preserve the one year filing window, and the provisional lapses, you will be out of luck. Of course if you have made significant improvements in the invention and the new improvements were not publically disclosed, you may be able to file a new application to cover the improvement. You really need to speak to a patent attorney or agent to determine to get a more specific answer to your question. Good luck.

A provisional patent application establishes a filing date for the contents disclosed in the provisional application. It expires automatically one year after filing and is never reviewed on the merits. The contents of a provisional patent application are never published and only become public upon being cited, typically as a priority document, in a subsequent nonprovisional (utility) application, or if you otherwise publicly disclose, sell, or offer for sale the invention, *e.g.*, "Prototype #1 has been sold repeatedly on the Internet for the past 3 years". The nonprovisional or utility patent application is usually published 18 months after filing and is reviewed on the merits by a patent examiner, thus forming the basis for patent rights if any are forthcoming as an issued patent. Because prototype #1 has been publicly sold for more than one year, patent rights to that invention have likely been forfeited. The invention in prototype #6 may or may not be patentable depending on whether it is novel and nonobvious in view of what others have done in the past (prior art). Prototype #1 is now prior art to prototype #6. It is not clear what you mean by "prototype #6 has the same utility function as #1". Prototype #6 may be patentable over prototype #1, if it has at least one feature that is novel and nonobvious over the prior art including prototype #1. A good strategy includes regular provisional patent application filings, followed-up, or preceded by, patentability searches to determine some confidence in obtaining a patent. In the favorable instances of patentability search results, you should consider filing utility patent applications (and international or foreign filings depending on your business strategy) within one year of provisional filing to secure the patent rights. To answer your last question, you could certainly proceed to filing a utility patent application, and the quicker you do so, the quicker you will obtain any patent rights forthcoming. Since you are ready to market prototype #6, the utility application makes more sense than filing a provisional because you don't need the extra year to determine whether you are ready to go to market.

Because #1 has been on the market for more than a year, it cannot be patented. You may be able to obtain a design patent on #6. Check with a patent attorney before you apply with the USPTO.

It might be possible. You need to have an attorney review the particulars.

You may be able to file a provisional or non-provisional application based on the design differences between prototype #1 and prototype #6, assuming the latter has not been sold in the past year, among other things.