Developing Your Invention
Inventors typically come to us with an idea of what they think is new about their invention. Usually, they have not done a prior art search, and as a result, are sometimes overly optimistic about the breadth of a patent they might ultimately obtain. Once we do a search, the scope of what is “new” – and hence what is protectable with a patent – often gets narrower. Of course, once a patent application is filed, we sometimes get a patent examiner who tells us it is even narrower than we thought.
Because of this, it is important to develop your invention – at least on paper – as much as possible before you file a patent application. Once you file the application, you cannot add any new information. If your application includes some implementation details, and you get hit with prior art that renders your initial claims unpatentable, you can use these implementation details to narrow your claims and distinguish the prior art. Without those details, you may be out of luck.
What kind of details are we talking about? Well, for an apparatus or device we are talking about things like geometry (shape/size), physical properties (e.g., tensile strength, hardness), and materials of construction (e.g., metals, plastics, or composites), and methods of use. For a chemical formulation, it may be key ingredients and their mass, molar or volume percentages. For an electrically implemented invention it may include things like voltage, current, resistance/impedance, circuit configurations.
For example, years ago we looked at some patents that took balloon catheters used for inserting stents during cardiac surgery and repurposed them for the opening of blocked nasal passages in nasal/sinus surgery. Is that type of repurposing patentable? In theory, yes. You can patent a new method of use for a known device. But if all you have is the raw idea of inserting a known balloon catheter into a nasal passage and expanding the balloon, you may have a problem getting a patent if the examiner deems the concept – at that level of breadth – to be unpatentable.
There is really both a substantive and a cosmetic issue here. The substantive issue is that you need some additional details about how the catheter will be designed and used with which you can limit your claims to distinguish the prior art the examiner asserts. The cosmetic issue is that if you do not have much detail about preferred shapes, sizes, materials of construction, and medical procedures, it gives the impression that you merely have an idea not an invention. This can be important to an examiner, but it can be even more important in litigation (assuming you succeed in getting a patent). An examiner can reject patent claims, and an accused infringer can invalidate them, if the specification does not provide a written description that 1) indicates you are in “possession” of the full scope of the claimed invention (the “Written Description Requirement”), and 2) teaches a person of ordinary skill in the art how to make and use the invention without “undue experimentation” (the “Enablement Requirement”). These types of implementation details are important for dealing with both requirements.
Without getting into the nuances of the legal doctrine, the key issue is whether your patent application includes the kind of details you a person skilled in the art would expect to see if someone really invented what the claims cover. So, returning to our nasal/sinus catheter example, here are some of the things a person skilled in the art might expect to see:
1. Preferred length and diameter ranges and the anatomical issues that dictate the best ranges
2. Flexibility/rigidity properties
3. Surface smoothness properties and their significance for avoiding trauma to the nasal passage
4. Preferred materials of construction
5. Key steps in surgical techniques
Having said that, there is a bit of a problem. When we ask inventors for these types of details, we inevitably get resistance and hear the same complaint: “But that’s not the invention”! Inventors are often frightened that we will are seeking these to limit the scope of what their patent application is intended to protect.
We’re not saying these details are the “invention.” They are not “the invention” until we put them in the independent claims, in which case they will narrow the scope of what that patent will cover. In the first instance, we always try to have some claims that are as broad as we believe the prior art will allow, but the examiner may disagree with us. If the examiner thinks the claims are too close to the prior art because of how broad they are, you may have no path to a patent unless we can limit the claims based on some of these details. To do that, the details must be in the specification when we file it. We cannot add them later.
On a related note, patents have independent claims and dependent claims. Independent claims are the broadest claims and do not refer back to an earlier claim. Dependent claims refer back to an earlier claim, and therefore, require all of the features of the claims they refer back to. In litigation defendants will be very aggressive — far more aggressive than a Patent Office examiner — in looking for prior art to invalidate your claims. If they successfully invalidate an independent claim, you can still win your case if you have a narrower dependent claim that is valid and infringed. So, the details we are talking about are typically included in dependent claims to provide a hedge against invalidation in an infringement case or in a Patent Office invalidation proceeding, such as an Inter Partes Review or Post Grant Review.