Is It Legal To File One Single Patent Application For Several Inventive Concepts?


I hear the faint-hearted always say: “You have to file one patent application for each inventive concept.”

And they are right, you will not pass the patent attorney qualification exam if you produce a patent application with a multitude of different inventive aspects in one single patent application.

But filing one patent application for many inventive is the version “deep pocket”. And many applicants do not have deep pockets.

The Core Problem

This is the core problem: the “one invention, one patent application” concept does not match reality.

The reality is this: all companies that are in the midst of developing a new product will invent many new features and variants in the process of doing so. There are even innovation techniques out there that encourage R&D teams to produce a multitude of features and variants for solving a specific problem and to later cull them down to a few alternatives. The company’s innovation strategy says to turn only these features and variants into a product that the customers are willing to pay for. And that is right! But there are a lot of features and variants left that are good, but they are not used. Maybe they are used at a later time, but not now.

It goes without saying that the company would file a patent application for these features and variants that are used in the current product. But what about those features and variants that are not used in the current product, but maybe only at a later time?

There is no company in this world that can afford to file a patent application for each new feature and variant that is conceived in such a bulk creative effort.

Solution: File All Inventions In One Single Patent Application

Yes, of course, can you do that. Virtually all jurisdictions in this world allow that.

Example, the Article 82, 2nd alternative, European Patent Convention (which is the same as the PCT Rule 13).

Unity of invention

The European patent application shall relate to one invention only OR to a group of inventions so linked as to form a single general inventive concept.

Most people stop reading that regulation after the first alternative: “one invention only per patent”.

But the same regulation applies if there are several features and variants in one single patent application. Just read the Article 82 EPC to the end and it says: “… or to a group of inventions so linked as to form a single general inventive concept.”

This aspect of Article 82 EPC is almost always overlooked. I would even say that it is always overlooked. My guess is that bureaucrats deliberately overlook it.

Please always remember the picture with the getaway boat above, it has as many as eight outboard motors (= “inventions”) on board. Each engine stands for one single inventive concept, which is a feature or a variant of an outboard motor. And still it is one single getaway boat (= “patent application”).

Filing A Single Patent Application For A Group of Inventions Will Not Create Problems at a Later Time

There is Art 27 PCT for National Requirements:

No national law shall require compliance with requirements relating to the form or contents of the international application different from or additional to those which are provided in this treaty and the regulations.

That means that if you have a PCT application and if this PCT application has a group of inventions, then the National Offices cannot say anything against it. They must treat this patent application just as a normal patent application. And that is also very often overlooked.

It Is Not Important at the Time of Filing Whether or Not These Many Inventions Form a Single General Inventive Concept

Whether or not the group of inventions forms a single general inventive concept will only be determined long after filing a patent application, namely during the search stage. And the patent application will be searched and examined for at least one of the multitude of inventions in it.

These are the consequences if you have several inventive aspects in one single patent application that do not form one single inventive concept:

  • you need to pay extra search fees if you want to search for more than one inventive concept, or
  • you need to clarify what inventive concept should be searched first, without paying an extra search fee.

In addition to that, the examiners may utterly complain in search reports and office actions. I will show you an example in my screencast video below.

How To Heal A Patent Application That Contains a Group of Inventions That Do Not Form a Single General Inventive Concept

The consequence of having a patent application that contains a group of inventions that do not form a single general inventive concept – in other words, the claims “lack unity” – is that at a later time, you need to file one or more a divisional or continuation patent applications for those excess inventions.


For the purpose of obtaining intermediate protection for all aspects of what you have invented, filing a patent application that contains a group of inventions that may not form a single general inventive concept is good enough.

And I wouldn’t mind much about a later complaint of the examiner. After all, the question of whether or not there is a lack of unity of these inventions can only be answered after a thorough prior art search. And this is what is expected from the patent office after a patent application has been filed.