Patent Infringement Analysis [with example] -Part-I

In simple terms, patent infringement occurs whenever a person exercises the exclusive rights of a patent holder without his/her authorization, within the country of patent grant and during the term of the patent. Upon analysis, a patent will be considered to be infringed only when the use of the infringing product or a process is within the ambit of the scope of a patent claim. Let’s see how a patent infringement analysis is done.

Types of Patent Infringement –


Literal Infringement

Literal infringement occurs when all the elements of the patent claim are inherently present in the infringing product/process. This is known as the All-Element Rule.

Let’s understand this by an example. The following is a claim for a bottle cap –

A bottle cap for use with a bottle, the bottle cap comprising a threaded neck, said cap being constructed of flexible plastic material and having a top wall, a cylindrical side wall depending from the top wall and a thread on the inner surface of the side wall for cooperating with the thread on the neck of the bottle.

The elements for this bottle cap are:

  1. A threaded neck
  2. A top wall
  3. A cylindrical side wall
  4. A thread

Now, let’s assume that the infringing product is

Image source:

We can see that the infringing cap has all the elements of our claim.

Thus the product is infringing our claim as per the all element rule.

Steps to ascertain literal infringement

At the very outset, every claim has 3 parts:

  1. Preamble
  2. Transition phase
  3. Body

After the transition phase, the rest of the part of the claim is the body of the claim.

Things to remember:

  • While doing comparison of your claim elements to that of the infringing products – ascertain the elements of the infringing products after ascertaining the elements of your claim. Do not compare the product elements to the elements of your claim, rather, compare the elements of your claim to that of the infringing product.
  • If all the elements are exactly similar then you have a case made for patent infringement.
  • Sometimes elements may differ as to the meaning of the word, in such cases, look at the description of the invention to understand the meaning of words that are used in claims.

For determining the meaning of the words in the claim, patent attorneys use two sources: Intrinsic sources – description and drawings, summary, abstract, title, prosecution history or file wrapper history; and Extrinsic sources – scientific dictionaries, scientific publications i.e. anything outside the prosecution of the patent.

Note that the infringing products would not always be so simple. There will be cases when it is difficult to ascertain the elements in the infringing product. For such cases, we look for infringement by equivalence. Infringement by equivalence occurs when the infringing product/process carriers on substantially the same function, in substantially the same way, and yields substantially the same resultThis is known as the Function, Way, Result Test. Infringement by equivalence will be covered in a subsequent post.

Image from here.

Siddhant Sharma

Siddhant is a Patent and Intellectual Property lawyer. He finds joy in exploring and writing about niche areas of law. He is finding better ways to describe the patent profession to a five-year old and a sixty-five year old.

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