Image source:

This article has been written by Vighnesh Kaimal, pursuing a Certificate Course in Intellectual Property Law and Prosecution from LawSikho.


Application drafting is arguably the most important aspect of the Patent filing journey of an inventor. The chance of getting a patent grant depends largely on the quality of drafting of patent specification. Moreover, a strong patent application essentially prevents competitors from competing with the invention, it makes it impossible for a competitor to work around it and build contending solutions. To achieve this level of “Patent lethality” a culmination of art and science is required. 

Patent Drafting essentially is an art wherein the draftsman is sufficiently able to express to the reader of the document the following things in principle:

  1. State of Art relating to the field of invention.
  2. Problems/Shortcomings in the Prior Art to deal with the problem adequately.
  3. The manner in which the new invention remedies the problems pertinent with the prior art.
  4. The working embodiments of the invention.
  5. The technical facets of the invention need to be protected (Claims).

In a patent application, the aim is to provide an accurate and detailed explanation of the invention in a way that highlights and clearly describes what the inventor thinks he has invented and wants the patent to protect. Unfortunately, many inventors make a variety of common errors when describing their invention.

There are three broad types of mistakes that occur during the drafting of a patent application:

  1. Mistakes in mentioning prior art.
  2. Mistakes made while drafting claims.
  3. Mistakes made in drawings.

Mistakes in the drafting Prior Art

Prior Art is everything known to the public before the filing date of a patent application. It includes prior patent literature, articles written in technological journals, an existing use case or any foreground information which exists on a particular subject matter relevant to the IP. 

A patent application has a section where the background of the invention is explained by the draftsman. It is here where the prior art relevant to the context of the invention is mentioned for the examiner’s reference. Its primary function in the application is to show what the state of technology is at the inception of the patent process. It also highlights the shortcomings and problems which the invention of the application intends to provide solutions for.

Common Mistakes made while defining Prior Art:

  • Explaining more than what is required: As long as it has any tangential connection to the invention, practically any art can be presented as prior art, nevertheless, quoting more than what is required can be dangerous to the application. All the prior art references used in a patent application are analyzed by the examiner to check for obviousness. The combination of multiple prior art references tends to limit the inventiveness of the proposed invention. Moreover, citing more than the required prior art increases the cost of the filing as well.
  • Making Admissions: In the United States, a statement made during patent prosecution identifying the work of another as prior art is called an admission. Admissions can be used by the USPTO to denounce the application as anticipating.
  • Reeking of Obviousness: A patent must be shown to be original against every single piece of prior art and a combination of them as well which is cited in the invention and the prior art should not be “anticipating” the invention. A claim is anticipated only if each and every element as set forth in the claim is found, either expressly or inherently described, in a single prior art reference. A relevant way to check obviousness here is the TSM method:
    • Teaching: Can the prior art mentioned in the application teach the reader the method of making the invention?
    • Suggestion: Can a prior art or the combination of prior arts suggest a method of producing the invention?
    • Motivation: Can a prior art or the combination of contents of multiple prior arts motivate a person skilled in the art to make the invention?

Mistakes while drafting claims

The claims of a patent are the “heart” of the application since it forms the most significant part of the whole application. The claims characterize, in specialized terms, the degree of protection a patent gets. Claims define what a patent owner gets the rights to exclude others from. The draftsman has to find the perfect language to write claims.

A Claim has the following parts:

  • Preamble: It defines elements of a physical apparatus of the claim and may also contain the objective of the claim. It includes machines, articles of manufacture, processes, compositions of matter, and products-by-process.

Example: (1) A Method for making tea.

(2) An Apparatus for scooping sand.

  • Transition: It is a phrase that links the preamble of a patent claim to the specific elements set forth in the claim. 

Example: (1) An apparatus, comprising of a handle, a counter weight and a rotating base…. (Open Ended)

(2) An apparatus, consisting of a handle, a counter weight and a rotating base…. (Closed Ended)

  • Body: It is the section where the draftsman recites the elements and limitation of the Claim.

Example: A game device, comprising: a handle; a head portion; and a protrusion.

Drafting of the claims is a game of harmonizing both the narrow and the broad. Choice of words and correct grammar plays a very important role as well. The goal is often to be “precisely vague.” Common Mistakes while drafting a patent application are:

Mistakes in Grammar: All claims are required to be proofread for grammatical errors and correct spellings.

Case Study: Flaky Dough or Charcoal Briskets?

Chef America, Inc. v. Lamb-Weston, Inc, 358 F.3d 1371

Chef America owned a Patent No. 4,761,290 for “a process for producing a dough product which is convertible upon finish cooking by baking or exposure to microwaves in the presence of a microwave susceptor into a cooked dough product having a light, flaky, crispy texture”.

The patent was a for a process to turn a large amount of dough into a flaky and crispy end product, and the improvement upon the prior art made by Chef America was that in the previously existing methods when a huge quantity of dough was baked it at once would cause them to either taste “leathery” or “soggy”.

The process patented by Chef America consisted of five steps, one of them was “heating the resulting batter-coated dough to a temperature in the range of about 400° F. to 850° F.”

When Chef America sued Lamb-Weston for infringement, US Federal Court held non-infringement. The rationale given by the court was that Lamb-Weston claims would heat the batter “at” the temperature in the range of about 400° F. to 850° while Chef America in its claims stated that they would heat “to” that temperature range.

Even while the attorneys for Chef America claimed that heating the dough to that temperature would produces a nonsensical result, since the dough would burn, the court stated that it was the duty of the patent applicant to reflect all of his idea into the patent application. It was not the duty of the court to write patents carefully and consistently

Drafting Broad Claims: Most inventors, in a bid to claim the most protection, or out of fear to of not explaining enough, draft claims which are very broad. This is a mistake which may result in examiner rejecting the application. Since defining the claim too broadly would mean seeking indefinite protection. There is also a fair chance that claiming too broadly can infringe another patent. 

Drafting Narrow Claims: Due to the certainty of thought which every inventor has about their invention, it is very difficult for them to think of an alternate embodiment. For example: A person who invents a cycle would two wheels not really care to make a claim broad enough to incorporate more wheels. This dilutes the protection a patent can afford to the inventor. Moreover, in the event the examiner rejects the claim, an inventor will have lesser scope to negotiate the scope of the claim.

Error in Transition: Each Transition word has its own special meaning. Using a wrong transition word can severely limit the chances of patent grant, or may even gravely limit the protections offered to a Patent despite the grant. 

Example 1:- “comprising” is an open-ended transition word. Consider this claim for a chair: –

“An apparatus comprising of a rectangular contour, with plurality of support legs and cross-sectional contour for back support”.

In the above claim would cover the legs, the surface to sit on and the back support. But since an open-ended transition is used it can also include anything one would care to mix (example: a charging slot or foot massager).

Example 2:- “Consisting” is a closed ended transition word. It excludes everything that has not been mentioned in the claim. Consider this example of a dishwashing liquid:-

“A admixture comprising of a acetic acid, soap and perfume”

In the above claim one cannot interpret it to protect any admixture with even one extra element other than acetic acid, soap and perfume.  

Inconsistency vis-à-vis Specifications:- The specification supports the claims. If the claims use terminology or mentions any functionality which is disjointed with the specifications it can cause problems at a later stage. There should be coherence between claim language and specifications. 

Indefiniteness in claims:- Patent right of monopoly is essentially similar to property rights, and just it is pertinent to define the boundaries of a piece of land, it is necessary to define the extent of the invention via claims. A claim must show how much an inventor owns and general public should be able to ascertain how much he does not after reading the application. The claims must particularly point out and distinctly define the metes and bounds of the subject matter to be protected by the patent grant.

Case Study: Dangers of Indefinite Claims

Nautilus Inc. v. Biosig Instruments Inc.

Biosig held U.S. Patent No. 5,337,753, for an invention to a bio rate monitor in the handles of exercise equipments. The claims described a “cylindrical bar featuring 2 electrodes on each half of the bar, mounted in spaced relationship with each other”

In a bid to get a licensing agreement, Biosig shared its invention with Stairmaster Sports, but the deal did not go through and Stairmaster Sports was shortly acquired by Nautilus Medical products.

Without entering an agreement however, Nautilus/StairMaster started to sell equipment featuring the patent technology belonging to Biosig. Biosig sued Nautilus for infringement, Nautilus in turn moved for a summary judgement on grounds that the patent was stuck by indefiniteness

Nautilus specifically claimed that Biosig’s patent for placement of electrodes and spacing claim lacked sufficient details as to the placement and size of the said electrodes.

US Supreme Court while ruling in favor of Nautilus held that “a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

Mistakes made in Patent Drawings

Drawings are not necessary to be a part of a patent application. In the United States a patent application is required to contain drawings only if such drawings are necessary to understand the subject matter and the textual description alone is not enough. In India, section 10 of the Patent Act says that the controller may require drawings if he so believes that it is pertinent to understand the invention.

Common Mistakes when it comes to patent drawings are:

  • Not following the specified regulations for drawings:- Almost all jurisdictions around the world have some or the other form of guidelines when it comes to drawings, it is paramount one follows them to avoid rejection. In India, drawings are regulated by Rule 15 of the Patent Rules, while in the United States, USPTO has put forth very specific rules for patent drawings, including things such as the quality of the ink and size of the paper and margins. European Patent Office also strictly follows Rule 46 of EPC Implementing Regulations.
  • Inconsistencies:- If patent drawings lack consistency, the examiner may not be able to ascertain the functioning. In some scenarios the patent application may survive the examiner’s scrutiny but may then face challenges in the event of a lawsuit. 


Case Study: A tight fit

Times Three Clothier LLC v. Spanx Inc.

Times Three Clothier held US patent 8,568,195 titled “Multi-Fabric Garment”. The invention was a fashion-forward women’s shapewear which was used for “slenderizing the midsection of a user”.

Times Three bought an action against a competitor Spanx for infringement of its design patent.

Spanx claimed indefiniteness vis-à-vis drawings, as the height of the material that was shown in a side view of the application drawing was inconsistent with the height of the material shown in a back view.

District Court for Southern District of New York found glaring inconsistencies in the drawings and thereby ruled in favor of Spanx. 

  • Non enablement due to ambiguity:- A person skilled in prior art should be able to recreate the invention by looking at the drawings without resorting to conjecture. The drawings must not rely on guessing skills of the expert to enable recreation.


Patent Filing can be expensive and litigation after the grant can be more so. The median patent litigation cost through post-trial (fees, expenses and costs) as per the American Intellectual Property Law Association ranges from $700,000 to $4 million. A lot of efforts are put in Research and Development by corporations before they draft patent applications, and any of the above-mentioned errors vitiate any benefit the invention may bring. In the light of the same it is necessary to avoid mistakes while drafting patent applications. 


Students of Lawsikho courses regularly produce writing assignments and work on practical exercises as a part of their coursework and develop themselves in real-life practical skill.

LawSikho has created a telegram group for exchanging legal knowledge, referrals and various opportunities. You can click on this link and join:

Follow us on Instagram and subscribe to our YouTube channel for more amazing legal content.


Please enter your comment!
Please enter your name here