Legal Definitions - obviousness double patenting

Obviousness double patenting is a principle in patent law designed to prevent an inventor from obtaining two separate patents for inventions that are not identical but are considered obvious variations of each other. Its primary purpose is to prevent an inventor from unfairly extending the period of their exclusive rights (monopoly) over a single inventive concept.

If a later-filed patent application claims an invention that would have been obvious to a person skilled in the relevant field, based on the inventor's own earlier patent, the later patent application may be rejected. This ensures that the public domain eventually benefits from inventions once a patent expires, without the inventor being able to secure additional, later-expiring patents for minor, uninventive modifications of their original work.

Here are some examples to illustrate this concept:

• Scenario: An inventor obtains a patent for a novel type of adhesive compound used in medical bandages. A few years later, they develop a slightly modified version of the same adhesive where a common, well-known additive is incorporated to make it slightly more flexible, without altering its core adhesive properties or its application. They then seek a new patent for this "improved" flexible adhesive.
  Explanation: The patent office might reject the application for the flexible adhesive under obviousness double patenting. If the addition of the flexibility-enhancing additive is a standard, obvious modification in the chemical industry for such compounds, and doesn't represent a truly new and non-obvious invention beyond the original adhesive, then granting a separate patent would improperly extend the inventor's exclusive rights over the fundamental adhesive technology.
• Scenario: A company patents a unique design for a smartphone case that features a specific shock-absorbing internal structure. Later, the same company files another patent application for a smartphone case that uses the identical shock-absorbing internal structure but is made from a different, slightly lighter plastic material, which is a common material substitution in manufacturing.
  Explanation: This situation could trigger an obviousness double patenting rejection. If merely changing the material to a commonly known alternative, without introducing a new, non-obvious inventive step related to the shock absorption or overall function, is deemed obvious to a skilled product designer, then a second patent would unfairly prolong the monopoly on the core shock-absorbing case design.
• Scenario: An engineer patents a method for optimizing traffic flow at intersections using a specific algorithm that adjusts signal timing based on real-time sensor data. A year later, they file another patent application for the *same algorithm and method*, but specify that it is implemented using a new, commercially available type of sensor that provides slightly faster data acquisition, a feature that is generally expected with technological advancements in sensors.
  Explanation: The patent office might apply obviousness double patenting here. If simply upgrading to a newer, faster sensor (which is an obvious technological progression) does not introduce a new, non-obvious inventive step to the traffic optimization algorithm or method itself, then granting a new patent would extend the monopoly on the core traffic management innovation.