You should almost NEVER file a provisional patent application. In virtually every case, a small company or independent inventor is better off by filing a complete, well-written, non-provisional patent application. Or file nothing at all.
One of the biggest hoaxes in the patent community is that provisional patent applications are a good thing. They are not. Here’s why: A provisional patent application ALWAYS hurts you.
Many people treat provisional patent applications as some kind of “shortcut” to getting “protection.” When this is done, a provisional patent application almost always contains two types of errors. Have some questions? Let's talk.
You can think about these errors as errors of commission or errors of omission. There is a misguided and completely false idea that you should include “as much material as possible” in a provisional patent application. This is an error of commission, where you put way too much information in a patent application.
A “thin” or “cheap” provisional patent application almost always has the error of omission: missing information that means you cannot support patent claims. (This is also an area where many patent attorney commit malpractice.)
Too much information? Not enough information? How can that be?
There Is No Such Thing As “Partial” and “Full” Patent Applications
One key thing to remember is that there is no “partial” patent applications (typically the provisional application) and “full” patent applications. Every patent application - every one - must have a complete description of the invention you want protected. A complete description means is to enable “one of ordinary skill in the art to practice the invention.”
In practical terms, this means that I must be able to take the patent application - and nothing else - and hand it to a machinist, programmer, or whoever will build the invention. That person must be able to build the invention using only the patent application as their guide, plus their ordinary skill. Most inventors - by definition - are of extraordinary skill.
When an inventor writes their own patent application, they often leave out things that are obvious to them, but these items can take a lot of work for somebody of ordinary skill. Any patent application that does not include the complete description of the invention is incomplete (we call it not “enabled”) and can be attacked or invalidated, or the examiner may reject it on that basis.
If your provisional patent application does not include everything necessary to hand it to someone else so that they can build the invention, your patent application creates prior art which will be used against you - AND it is too weak to get enforceable patent claim. This is the worst of all possible outcomes.
Provisional Patent Applications Are PRIOR ART Against YOU Later
Anything that you put in a patent application that is not claimed is information that is not protected, but even worse, it is given to the public. Even worse still, ideas that are in a patent application that is not claimed will become PRIOR ART AGAINST YOU when you get around to building that product.
One of my clients used to write his own provisional patent applications. This was for Lithium ion batteries. Several years later, after his first patent application issued, we began working on a really critical project that had wide ranging possibilities: we wanted to add fibers into the battery that would prevent fires. After a year or so of very intense research, we filed a patent application with our solution.
Turns out that the patent examiner looked at the inventor’s original patent application - the provisional patent application that he filed many years ago. In that original provisional application, the inventor mentioned - in one single sentence - that it was possible to add fibers to the battery. The reality was that fibers were very difficult. If they are too short, they are ineffective. If they are too long, they turn into spaghetti. They are very difficult to disperse in the mixture. During the casting process, the fibers sink to the bottom.
It took us a year to figure out how to get fibers into the product, and the research was very difficult and ultimately very successful.Our fiber-based patent application was rejected with our own provisional patent application cited against us. The net result: the company went bankrupt.
This example is one of both omission and commission.
The error of commission was that the original provisional patent application had unclaimed material. The error of omission was that there was not enough description to support patent claims. Both of these errors contributed to our lack of patent protection and, eventually, the demise of the entire company.
Provisional Patent Applications Will Be Publicly Available
There is a myth that provisional patent applications are secret and not publicly available. It is true that they are secret, but NOT when a non-provisional application claims priority to it. The provisional application WILL become publicly available when the non-provisional application is published or issues.
It is true that provisional patent applications will never see the light of day if they are abandoned. But nobody ever intentionally files a patent application that they intend to abandon right away.
A Provisional Patent Application Wastes Time.
With all the talk about how provisional patent applications are often technically bad, here is the real issue: A provisional patent application wastes your most valuable asset, which is time. The faster you get an issued patent, the faster you can license or sell the patent, the faster you can enforce the patent to keep competitors out of your space, the faster you can raise money using the patent as collateral.
In every single instance, the faster you can get an issued patent, the better off your business prospects will be.
A provisional patent application is designed to DELAY getting a patent. It DELAYS the start of examination for up to a year. Think about it: are you better off with an issued patent or with a pending application? In every case, you are better off with an issued patent.
But I Want To Add To My Invention In A Year…
One of the poor excuses people have for doing a provisional patent application is that you don’t have enough information to file a “full” patent application because you know you will be developing more information over time. As your research and development progresses, you expect to have more information that you want to add.
The myth is that provisional patent applications were designed for this very thing. There is nothing further from the truth.
Additional information can be added to ANY patent application - provisional or non-provisional - by a Continuation-In-Part application. This can be done the next day after filing a patent application or several years later, provided that the original patent application is still pending. What is the cost? Only a $800 filing fee. (All fees referenced here are US small entity fees.)
A Provisional Patent Application Shows Your Ignorance To Investors
A provisional patent application shows your utter ignorance of the patent system to possible investors. The cost difference between a provisional and non-provisional patent application filing fees is about $600. (About $150 for a provisional application and $750 for a non-provisional.)
You are sending a very clear message to your investors that you don’t believe that your patent application is not worth the measly $600 extra to file it as a non-provisional application. Yet at the same time, you are trying to get the investors to believe that the patent application is worth a lot.
You are showing your investors that you don’t know how to get enforceable protection for your business, and you are treating them with contempt by demonstrating with your actions that you don’t believe that your asset is any good. Why not just pay the extra $600 if you believe in the invention?
Any Attorney Who Files A “Cheap” Provisional Patent Application Is Probably Committing Malpractice.
Any registered practitioner who will file a “thin” or “cheap” provisional patent application is probably committing malpractice. Every client who comes to a practitioner and wants patent protection expects to actually get it, and it is the practitioner’s responsibility to provide patent protection. The client cannot tell a good patent from a bad one, but the practitioner can. The practitioner knows what is a properly explained invention and therefore what will give the client protection.
Many patent agents and patent attorneys will file “cheap” or “thin” provisional patent applications with the excuse that the “client approved it,” "the client did not have enough money," or that the “client only wanted something very cheap.” The only appropriate thing for a practitioner to do in this case is to reject the client and state that they cannot represent them in this matter.
If you find an attorney who will file a provisional patent application - tell them thank you and go find a different patent attorney. You will be better served.
Provisional Patent Applications Are Simply The Worst Thing You Can Do.
There is no business scenario where provisional patent applications are a good thing. If you are trying to “save money” by doing a provisional patent application, you will spend far more money and get much less protection than you expect.
So why are there provisional patent applications? The simple answer: Big Pharma. Big Pharma makes their money at the end of the patent term, not at the beginning. The net effect of a provisional patent application is that it delays examination, but also delays the start of the patent term, meaning that the patent expires 21 years after initial filing, not 20 years like if you filed a non-provisional first.
There is NO business reason for a startup company (or any company who is not Big Pharma) to ever file a provisional patent application.
This answer was also published on Quora here.