The object of patenting an invention is to provide the benefits reaping out of such an invention to its inventors. This benefit awarded acts as an incentive to inventors, hence increasing the output of inventions. The benefit awarded, including the right to prohibit, should be utilised in a controlled environment as misuse could lead to the downfall in the amount of new inventions. In order to balance the rights awarded to an inventor and the protection given to prospective inventors, 'patent scope' has to be identified for every patented invention.
Patent scope refers to the collection of claims to which the patent holder is entitled. Subservient patent and dominant patent are two classifications of patents that differ on the scope of rights they accompany. These scopes are determined through application of doctrine of enablement and doctrine of equivalents.
Doctrine of enablement reduces the scope of a patent holders rights against future technologies in order to maintain incentives for further inventions and advancements. Doctrine of equivalents, on the other hand, increases the scope of a patent holders' rights beyond literal boundaries. The test adapted is whether a new technology performs the same function as the previous invention or whether the new invention causes the older invention to operate in a substantially different manner.
Dominant patents are those patents that are assigned to new inventions that have no prior art. These have a wider assortment of rights as they are the first of that kind. Any invention that is similar to such a patented invention can be challenged by such a parent holder for infringement. Subservient patents are those patents that are assigned to inventions that are an improved version of an already patented invention. The holder of such a patent has narrower assortment of rights.
A subservient patent is allowed only when such an inventor proves the improvement on the existing patent passes the test of non-obviousness, utility and novelty. This is a situation where it is accepted that the invention infringes a portion of a broad dominant patent, but as they satisfy the test of patentability, a subservient patent is allowed. The doctrine of enablement and reverse equivalents are used in case of assignment of subservient patents.
A dominant patent holder and a subservient patent holder block each other’s patents regarding different aspects based on their respective right of prohibition. The dominant patent holder is prohibited from using the improved version of invention for which the patent is held by the subservient patent holder. Likewise, a subservient patent holder is prohibited from practicing his invention without the license of dominant patent holder. The broader patent holder is told to ‘dominate’ the subservient patent holder on his exercise of patents.
An invention can directly claim to be registered for a subservient patent, but the format followed for making such a claim has to be through the Jepson Claim format. Through this format, the claimant claims that his/her/their invention is an improved version of a prior art; but this need not be the only way of receiving a subservient patent. The final decision is laid in the hands of the patent office authorities.
Subservient patents should be a last resort for any applicant as it creates numerous encumbrances on the rights of the patent holder. In contrast, it can also act as a bargaining tool to block the use of the improved invention by a dominant patent holder. In addition, this bargaining power can be leveraged to land a licensing deal.
In conclusion, the concept of dominant and subservient patents are a necessary measure for accommodating new inventions and technological advancements. No right provided can be absolute in nature. Subservient patents can be allowed as it provides larger public advantage than the relative disadvantage caused to the dominant patent holder’s rights as long as it passes the test of non-obviousness and inventive step.