As patent law continues to evolve, so does the doctrine of pith and marrow in
patent infringement cases. This doctrine is an important concept that addresses
the issue of a patent claim's core, essential elements and how they relate to
the claims of infringement.
The pith and marrow doctrine, also known as the substance of the invention
doctrine, is a tool used to determine whether or not a particular product or
process infringes upon a patent claim. It involves a careful analysis of the
patent claim to determine its essential features, and then compares those
features to the allegedly infringing product or process.
In essence, the doctrine of pith and marrow requires courts to look beyond the
literal wording of a patent claim and instead focus on what the invention
actually does. This is important because many patent claims can be written in a
way that is intentionally vague or overly broad, which can make it difficult to
determine exactly what the patentee is claiming as their invention.
For example, suppose a patent claim is written to cover a "device for moving
objects from one location to another." At first glance, this claim could be
interpreted to cover a wide range of possible devices, from a simple conveyor
belt to a complex robotic arm. However, by applying the pith and marrow
doctrine, a court could determine that the essential feature of the invention is
the ability to move objects in a specific way or using a particular mechanism.
In one of the recent Judgement passed by the Hon'ble High Court of Delhi , in
relation to a Patent pertaining to Automatic Tube Cleaning System, the Hon'ble
High Court of Delhi has once again applied this doctrine to render the Judgement.
The facts of the case and the Judgement has been detailed herein below:
The Subject Matter Patent:
IN 382118 in respect of an Automatic Tube Cleaning System (ATCS). This is an
invention as claimed by the Plaintiff is system by which tubes and ducts in
air-conditioning system are kept clean.
The Patent was granted on 18.11.2021 with effect from 13.04.2012.
The Essential Feature Of The Subject Matter Patent:
A system comprising, inter alia, of at least:
- Two collectors.
- Two pumps.
- One trap.
- One sorting system
- One counting system.
Defendant Impugned System:
The Bone Of Contention:
- One Pump
- No Sorting System
- No Counting System
The Plaintiff alleged that the Defendant has copied the essential feature of the
subject matter Patent.
On the contrary, the Defendant highlighted the differences between both the
competing products of the parties.
This argument of the Defendant was sought to be disputed by the Plaintiff the
incidental differences between the AFCS and ATCS notwithstanding, the pith and
marrow of the ATCS stand replicated in the AFCS; ergo, patent infringement has
The Issue At Hand:
- What is Pith and Marrow Doctrine and how it has to be evaluated?
Pith And Marrow Doctrine:
The Court has to outline the essential feature of the subject matter Patent,
i.e. the Pith and Marrow of the Patent. In the other words , this doctrine says
the necessity of pointing out the essential feature of the subject matter
Patent. Pith and Marrow of the Patent simply refers to essential features of a
How The Pith And Marrow Of A Patent Can Be Outlined?
In order to appreciate the essential feature of Patent, it is not proper to read
claims of Patent first and then the specification. Rather the proper way is to
read the description of the Patent first and then the claims.
Dichotomizing the claims and the accompanying specifications is, therefore,
contrary to the most fundamental canons of patent law.
Pith And Marrow Of The Subject Matter Patent:
All the afore mentioned element as mentioned in Para No.9 of the Claim are
unalienable part of the subject matter Patent.
From reading of the summary of the invention as provided by the plaintiff itself
in the complete specifications of the suit patent, the Hon'ble Single Judge
reached on the conclusion that two collectors having two separate functions, two
pumps, a Ball Trap, a counting system, a sorting system and an electronic
controller are identified and underscored as the essential features of the suit
Even at the stage of reply to First Examination Report, the Plaintiff itself
asserted that afore mentioned element to be essential features of the subject
As all the afore mentioned essential element of the subject matter Patent were
missing in the subject matter Suit Patent of the Plaintiff were missing in the
product of the Patent, the Court declined the relief of interim injunction for
infringement of Patent.
The Comment On Pith And Marrow Doctrine:
Thus we have seen that this doctrine requires outlining the essential feature of
the Patent. Once the essential features of the patent claim have been
determined, the court can then compare them to the allegedly infringing product
or process to see if they are the same or substantially similar. If they are,
then the court may find that there has been patent infringement.
The pith and marrow doctrine has been used in a variety of patent infringement
cases, including ones involving pharmaceuticals, computer software, and
mechanical devices. It can be particularly useful in cases where the patent
claim is written broadly or is difficult to interpret, as it allows the court to
focus on the actual function of the invention rather than just its literal
One important caveat to note is that the pith and marrow doctrine is not a
substitute for a careful analysis of the patent claim itself. While it can be a
useful tool for determining whether or not there has been patent infringement,
it should not be used to completely disregard the language of the patent claim.
Overall, the doctrine of pith and marrow is an important concept in patent law
that helps to ensure that patentees are receiving adequate protection for their
inventions. By analyzing the essential features of a patent claim and comparing
them to the allegedly infringing product or process, courts can make informed
decisions about whether or not there has been infringement, and help to maintain
the integrity of the patent system as a whole.
As we have seen that in the present case, the Hon'ble High Court has refused to
grant the injunction in favour of the Plaintiff, as the Defendant has not used
all the essential features of the Plaintiff's Patent (the pith and marrow of
Plaintiff's Patent). This is another aspect that Plaintiff's own admission to
FER report helped the Hon'ble Court to outline the essential feature of the
subject matter Patent.
The Case Law Discussed:
Case Title: Ecomax Solutions Pvt. Ltd. Vs Energo Building Solution LLP
Judgment date: 20.03.2023
Case No: CS(COMM) 366/2022
Neutral Citation No. 2023:DHC:2334
Name of Court: High Court of Delhi
Name of Hon'ble Justice: C Hari Shankar, H.J.
This information is being shared in the public interest. It should not be
treated as a substitute for legal advice as there may be possibility of error in
perception, presentation and interpretation of facts and the law involved
Written By: Ajay Amitabh Suman, IPR Advocate,
Hon'ble High Court of Delhi
Ph no: 9990389539, Email: [email protected]