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Patenting an Improvement on an Existing Patent

ImprovementCompany 2 celebrating GB2 © Alphabet IP

It is not uncommon to develop a patentable technology, such as a product or a process that is an improvement on one that already exists – and which may well be owned by someone else.

Research and development is often based on identifying and exploiting gaps in the state-of-the-art technology after a technology landscape study or a literature review.

Making improvements on already existing technologies is one of the ways in which technological development occurs and increases in efficiencies can be achieved, for example, where material performances can be maximized and manufacturing costs can be further reduced.

However, what happens when an inventor develops a patentable invention that is an improvement over an already existing patented invention?


An invention that is an improvement over an original invention is still a patentable invention if it comprises features that are novel and inventive over the original. The original can be viewed as “prior art” and for the purposes of patentability, the Patent Office isn’t really interested in the legal status of the original invention.

This means that whether or not the original product is disclosed in a scientific journal publication or is subject matter from a patent that is still in force is not really a concern for the Patent Office. In either case, the journal publication and patent are assessed by their date of publication being before the filing date of the patent application as prior art – used for examining whether or not the patent application in question is patentable.

So if an applicant or inventor comes across some information in the public domain and then has a eureka moment and ends up developing an ‘improvement’ to what they had previously come across, then their improvement may well be the subject of a patentable invention. The information they used – is simply, prior art.

The legal status of the prior art is not really in question when it comes to patentability. Instead, the main issue is whether the original information was publicly available, i.e., that the applicant or inventor was free in law and equity to access the information, and that it was not otherwise confidential information and that there was no breach of confidence.

The Patent Examiner needs to assess the search results, i.e., the subject matter that forms part of the state of the art that was made available to the public prior to the priority date of the patent application. If so, then the Patent Examiner will assess the prior art – including the original information in the above example – against the novelty and inventiveness of the patent application.

If the improvement is novel and inventive, and meets the requirements for patentability, then a patent will be granted for the improvement.

However, the question arises – what if the information that the improvement was based on is a patent? and what if that patent is currently in force?

If the improvement is based on a patented technology – and even if the patent is in force – then for the purposes of assessing the patentability of the improvement, the patented technology is still only relevant as prior art.

Patent Rights:

A patent grants exclusive rights to inventors or assignees, allowing them to prevent others from infringing on their invention. In exchange for disclosure, a proprietor can benefit from a period of exclusivity – of up to 20 years – to exploit their invention.

Consider the scenario where Company 1 has a patent GB1 for a wind turbine blade that is currently in force; and Company 2 filed a patent application GB2 for an improved wind turbine blade that is based on GB1. The improvement relates to the contour of the blade that improves the efficiency of the blade in generating wind energy.

Company 2 is successful in obtaining a granted patent for GB2 because the improved wind turbine blade is novel and inventive over Company 1’s GB1.

The question is, what rights does Company 2 have in relation to its newly granted patent? Well, according to the definition mentioned above, Company 2 has the exclusive right to prevent others from undertaking infringing activities against its improved wind turbine blade as claimed in its granted GB2 patent.


According to the UK Patents Act 1977 – where the invention is a product, a person infringes a patent in force in the UK when he makes, disposes of, offers to dispose of, uses or imports the product or keeps the product for disposal or otherwise without the consent of the proprietor.

These are the sort of ‘infringing acts’ that can get you into trouble and you may be liable for damages or other remedies if you knowingly infringe on a patent in force in the UK.

Referring back to the aforementioned example, Company 2 does not itself have the right to use its own patented invention as that would be an infringing act on Company 1’s GB1 which is currently in force. This is because GB2 was based on GB1, and GB1 is a patent that is in force.

Company 2 with its improvement patent is in quite a unique position – it can stop others from infringing on its patent, but it does not itself have the right to work its own patented invention as this would be infringing on Company 1’s patent.

This scenario explains why, when it comes to “improvements” made on existing patents, there is a need to distinguish between patentability and infringement. It may be possible to obtain a granted patent for an improvement over an original patent, but not the rights to work the invention without infringing on the original patent. So what options does Company 2 have?

Company 2 can only really license its improvement over Company 1’s GB1 patent because it does not itself have the rights to GB1. Therefore, the simplest option is for Company 2 to license its patented technology to Company 1. By attempting to license its patented technology to a third party, Company 2 would be inciting the infringement of Company 1’s patent, unless the third party already has a license from Company 1.

Another option may be for the two Companies to cross-license their patents. This is where, for example, there is a mutual benefit – Company 2 requires a license for GB1 from Company 1 to work the improvement i.e., GB1+GB2, and Company 1 requires a license for GB2 from Company 2 to work the improvement, i.e., GB1+GB2.

Such a cross-license would largely depend on the value of the improvement, and whether the two Companies would be willing to work together in this way. In some industries, even where the Companies are competitors, they may still be willing to work together where the improvement carries significant value.

Sometimes competition is too fierce and neither party can benefit. In other instances, Company 2 may simply sell the improved technology to Company 1, which may be interested in buying the technology outright. GB2 could be assigned to Company 1.


In conclusion, the patenting of improvements necessitates a meticulous balance between exclusivity and collaboration.

While obtaining a patent for an enhancement confers exclusive rights, the specter of potential infringement looms, particularly when the improvement is based on an existing patented technology.

The essential differentiation between patentability and infringement becomes apparent as inventors face the paradox of possessing rights to an innovative improvement that can be patented but which may not necessarily be implemented without encroaching upon another’s existing patent that is in force.

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