Common Mistakes to Avoid When Filing a Patent Application

Filing a patent application can be fraught with errors that cost you money, time and resources. Be sure to avoid these missteps at all costs!

A common error is waiting too long to file for protection abroad, which can result in the loss of that protection and costly litigation.

1. Failing to disclose the invention in sufficient detail.

Filing a patent application is an integral step in the process of protecting your invention. Unfortunately, filing one can be time-consuming and costly. Therefore, it is critical that you do not make any errors while filing your application to safeguard the value of your valuable creation.

Many applicants make the mistake of failing to disclose their invention sufficiently in detail. This can be a costly error, as it may lead to rejection by the examiner of one or more claims.

It is especially a concern for inventors working pro se. These individuals may fail to include drawings that meet the requirements set out in the Manual of Patent Examination Procedure (MPEP).

The USPTO requires inventors to provide detailed explanations of their drawings in a written description. Failure to do so may result in rejection by an examiner if there are not sufficient explanations provided.

Another common mistake is failing to describe an invention in a manner understandable by those with ordinary skill in the art. This implies that the inventor must use clear and exact language so someone competent in this field can create the invention with ease.

Making the invention readable is paramount as this will determine whether the patent claims are valid or invalid. Furthermore, you must provide a comprehensive disclosure of your invention so that anyone reading the patent can comprehend how to utilize it effectively.

Insufficient disclosure can be especially problematic in high-stakes cases when the court must decide if a patent was invalidated for lack of enabling description support. In these instances, courts have held that the written description of the claimed invention must be sufficiently precise to enable someone with ordinary skill in the art to practice it.

The written description of an invention is the primary document required for filing a patent application, outlining how the inventor believes their invention to be unique compared to other discoveries and outlining what monopoly rights they believe they possess over it. Furthermore, this specification contains evidence that the invention belongs solely to the person who filed the application.

2. Failing to include sufficient drawings.

If you want to increase the odds of receiving a patent, one key step is including sufficient drawings. Drawings make claims more precise and allow potential licensees to better comprehend how your invention functions.

Lacking sufficient drawings in your patent application can have a disastrous effect on its outcome, potentially resulting in neither receiving a patent nor being rejected by the USPTO. The USPTO has strict rules for including drawings in patent applications, so if yours doesn’t adhere to these guidelines, then it will likely be rejected by them.

When filing a patent application, the most essential thing to remember is that the drawings must adhere to the specifications contained within. This means they must display each feature described in the specification.

Another type of drawing, known as an exploded view, can be used to demonstrate how each part of your invention fits together. This is a great way to explain the intricate workings of your product to potential licensees and manufacturers because it helps them comprehend how different elements interact and why they’re essential for its functionality.

Another type of drawing that may be beneficial in your patent application is a 3-D rendering of your invention. This kind of visual aid is especially valuable when trying to attract licensees and manufacturers, since it makes the invention appear very real.

From our years of experience, we have identified the most frequent mistakes to avoid. If you are thinking about filing for a patent, working with an experienced attorney is highly recommended to ensure your application is properly prepared and protected against future challenges.

A patent is the legal authorization to manufacture, utilize and commercialize an invention. These intellectual property rights were designed to spur people on to develop novel ideas and produce innovative products.

3. Failing to include sufficient claims.

A patent is a government grant that gives an inventor exclusive rights to an invention for a specified period of time. In the United States, patents can be issued on various inventions and processes such as utility and design patents.

To obtain a patent, an applicant must file an application with one or more claims that accurately describe their invention. Additionally, the drawing or diagram typically included with the application serves to visually represent the concept being protected.

Unfortunately, many applicants fail to include enough claims that accurately describe their invention. This can lead to patent infringement litigation and should be avoided at all costs.

Particularly, this can cause delays of several years in prosecution. In such a scenario, there could be an implied presumption that the patentee violated the law by filing multiple continuation applications and thus prolonging the process.

The presumption can be overcome if an applicant can demonstrate that they did not break any laws but instead acted in good faith to obtain a patent. Furthermore, this is an equitable defense to delays during the prosecution process.

But if this argument is accepted, it would completely demolish the doctrine of prosecution laches. Additionally, it would negate any presumption that a delay in the process was due to an interference, an oversight on behalf of the PTO or secrecy orders which prevented issuance of patents.

Another rationale why the law allows applicants to revise their claims is that words often do not suffice when it comes to accurately describing inventions. Furthermore, patentees have the option of seeking a reissue within two years of the initial issue date if they are dissatisfied with their submission.

Alternatively, an applicant can rely on the doctrine of equivalents to argue that a competitor’s product infringes even if it does not strictly conform to her claims. Furthermore, this doctrine provides protection to patent owners who drafted their claims too narrowly, since more effective protection may have been available.

Though not as widespread as some have claimed, abuse of the patent prosecution process should still be addressed. We suggest several ways in which Congress and courts can strengthen existing rules to reduce abuse while still preserving continuation practice rights.

4. Failing to include sufficient references.

Sufficiency of disclosure is a fundamental requirement under patent law that applicants disclose their invention sufficiently so that someone skilled in the art could execute it. It plays an integral role when determining whether a patent should be issued and is especially critical when dealing with technologies like drugs.

One of the biggest mistakes brand-name drug manufacturers make is not including enough references when filing a patent application. This can cause delays in prosecution or rejection of many claims submitted for patent protection.

Often, the initial step in the patent application process involves an examination by a patent examiner. They will review the application and conduct a search of prior art to ensure it complies with patent law. If satisfied, they will issue a positive opinion on the patent application.

Next, the examiner will decide whether the subject matter of the application is obvious or non-obvious. If they determine that claims made in the application are not obvious, they are likely to issue what’s known as a “Final Rejection” to the applicant.

Once a rejection is received, the applicant can either argue that their patent is not obvious or reduce its scope. Alternatively, they could file for a continuation application – useful if someone attempts to design around your original patent and makes minor variations that wouldn’t be protected under your initial protection.

The issue with continuation applications is that they have been exploited to circumvent patent laws. This practice has led to abuse of the patent system and, consequently, should be abolished.

In addition to banning continuation applications, policy makers should strengthen existing regulations. Doing so will help limit abuse while safeguarding public interests by ensuring that bad patents aren’t issued and upheld in court.

Another way to reduce the number of bad patents issued and upheld in court is by increasing the fees charged for filing a large number of references. Currently, filing an unlimited number of references costs only $180; increasing this fee to $1,000 or $2,000 better reflects the costs associated with reviewing high-reference patents.

Why Startups File Patent Applications

Patents grant inventors temporary monopoly rights on inventions. Patents may be used to deter copycats, provide bargaining chips in licensing negotiations and signaling devices that attract investors and customers. These benefits are argued by scholars and policymakers to offset the social costs of patent rights. Because startups have limited assets and no other protection mechanisms, they may be able to derive large private benefits from patents. 

The Cato Institute in cooperation with the USPTO analyzed 34,215 patent applications that were filed at the USPTO as a first time in 2001 and received a final decision on December 31, 2013.  Cato estimated that winning the patent lottery increases the startup’s chances of obtaining a patent by randomly drawing an examiner who is more likely to approve the applications. This compares to startups that have only randomly chosen underlying inventions and fail to get a patent. These estimates show that a patent can result in an average of 16 additional employees and $10.6million in additional sales for the five years following the winning of the patent lottery. This increases the likelihood of the firm being granted a second patent by 56.5 percent, and the quality of those patents (with the average number citations per patent increasing by 33%).

Contrary to the obvious benefits of a first patent, subsequent ones are less beneficial. Although the researchers at Cato don’t see any evidence that second patent applications increase sales or employment growth, it does increase the number by 49.8 per cent. Similar patterns are observed when a third patent is approved. These findings suggest that patents have a changing value over time. When startups have little other assets, securing a first patent allows them to invent and launch a high-growth path. The subsequent patents are a way to encourage more innovation, but they play less of an impact on growth. This is likely due to the fact that startups may have acquired other resources along the journey.

With that background in mind, let’s examine the patenting journey and discuss potential pitfalls to avoid next.

Patent Basics

A patent is a property right: It is right to exclude others from making, using, selling, offering for sale or importing the claimed invention for a limited term. A patent is territorial and protection is only in country that granted patent; no world-wide patent.

However, an international patent application is possible. An international patent application is filed under the Patent Cooperation Treaty, (PCT). It aims to make it easier for inventions to be protected in multiple countries cost-effectively and in an insightful manner. To seek protection in all member states of the PCT, an applicant must file one international patent application under PCT system.

Patent application process is complex and lengthy and one is prone to mistakes in the process. This article will highlight the patent application process and some of the common mistakes people make, in addition to the post filing support. The detailed information below is only applicable to US patent application.

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Types of patents

Utility patent: Any new and useful process, machine, article of manufacture, or composition of matter, or any new and useful improvement thereof.

Design patent: A new, original, and ornamental design for an article of manufacture

Plant patent: any distinct and new variety of plant that is invented or discovered and asexually reproduced.

Provisional vs. Non-provisional

Image credit: USPTO

Benefits of provisional utility applications 

  1. The Inventor is given time to investigate market potential.
  2. Inventor may file multiple provisional applications during the 1- year pendency of the first filed provisional to include improvements.
  3. Provides time to obtain counsel if desired.
  4. Patent term measured from filing date of subsequent non-provisional application.
  5. Term patent pending allowed to be used.

Utility patent applications

Image credit: USPTO

Anatomy of a patent publication

Image credit: USPTO

Filing requirements of a non- provisional utility patent application

  • A specification, including a description and at least one claim.
  • Drawings, when necessary for an understanding of the invention.
  • Inventor information including the legal name, residence, and mailing address of each inventor.
  • Oath or declaration or an application data sheet.
  • The prescribed filing, search, and examination fees.


Filing fees paid in full (surcharge if submitted after filing date)

  1. Non-electronic filing fee for applications submitted in hard.
  2. copy (mailed or hand-carried to the USPTO)
  3. Excess claims fees.
  4. Application size fees.
  5. Fees for large sequence listing submitted/transferred.
  6. Other fees as applicable.

•Fees paid according to the entity status established at the time of payment.


A surcharge (in addition to any other fees due) will be assessed for:

  • Late submission of the basic filing, search or examination fee.
  • Late submission of inventor’s oath.
  • Filing an application that does not contain at least one claim on filing.
  • Submission of an application filed by reference to a previously filed application.

Office of Patent Application Processing (OPAP)

OPAP Performs an initial review of the application papers for completeness and compliance with procedural requirements, including inspection of drawings to see if they can be effectively scanned and adequately reproduced.

This is a separate standard from what the patent examiner will subsequently review during examination. If deficiencies are found, OPAP will send an Official notice of the deficiencies and set forth a time period for response to avoid abandonment. Once the application is accepted as complete by OPAP, it will be assigned for examination

Common filing mistakes

  1. Specification Format
  2. Drawing Format
  3. Application Data Sheet (Form PTO/AIA/14)
  4. Signature Requirements
  5. Micro Entity Certification (Form PTO/SB/15A)

Specification page format

  • The specification, including the abstract and claims, must be written in English and have lines that are 1.5 or double-spaced in a single column of text
  • Written on only one side in portrait orientation
  • 8.5 by 11 inches with all margins of at least ¾ inches except for a left side margin of at least 1 inch
  • Clearly typewritten in non-script font (e.g., Arial, Times New Roman, or Courier, preferably with a font size of 12), without shading, on white paper
  • The application pages must be numbered consecutively (centrally located above or below the text) starting with page one
  • Drawing figures should not be contained within the specification

Specification sections

1.Title of the Invention (short and specific)

2. Most common applicable sections

  • Background of the Invention (e.g., state of the art before your invention)
  • Brief Summary of the Invention
  • Brief Description of the Drawings (list of all figures by number with brief statement of what the figure depicts)
  • Detailed Description of the Invention

3. Claims (on a separate sheet)

4. Abstract (less than 150 words, one paragraph, on separate sheet)

How to file a substitute specification

There are three required parts of the Submissions:

  • Marked-up copy with proper markings showing all the changes relative to the immediate prior version of the specification of record
  • Clean copy (without markings)
  • Signed statement that the substitute specification contains no new matter

The entire specification is required for the marked-up and clean copies, not just the amended portion.

Marked up vs. clean copy

Marked up copy:

  • A version that shows ALL changes to the most recent specification of record with markings.
  • Additions of text are underlined.
  • Deletions of text are shown by strike-through, except double brackets may be used to indicate deletion of [[five]] or [[fewer]] characters.

Clean copy:

  • A version that includes ALL changes to the most recent specification of record without markings.


It is required if necessary to understand the subject matter to be patented. Drawings necessary to understand the invention cannot be introduced after the filing date

Drawing Requirements

  1. Black and white drawings; lines; numbers heavy enough to permit adequate reproduction.
  2. Use reference characters (in specification and drawings; numerals preferred).
  3. Each Figure must be labeled in English (e.g., FIG. 1) with a corresponding description in the Brief Description of the Figures.
  4. Contain little or no text, and no non-English labeling or text.
  5. Be on white, non-graph, 8.5 by 11 paper, with margins of at least ¾ inch and a left margin of at least 1 inch.
  6. Be free of erasures, copy marks, overwriting, interlineations, folds, and alterations.
  7. Numbering of the sheets of drawings should be numbered. In the top-center of each sheet, the number should be shown by two Arabic numerals placed on either side of an oblique line, with the first being the sheet number and the second being the total number of sheets of drawings, with no other marking.

Common mistakes found during OPAP drawing review

  • Line quality that is too light to be reproduced
  • Missing lead lines
  • Excessive text or text that is not in English
  • Paper format (e.g., margins and paper size)
  • Incorrectly labeled figures
  • Photographs that are illegible after scanning
  • Color drawings without a petition
  • Each figure described in the brief description of the drawings must correspond to a separately-labeled drawing figure
    • Fig 1 described in the specification should not be labeled as Fig 1a
    • Fig 1a-f described in the specification should not be labeled as Fig 1

How to make amendments to the drawings

1.Each sheet must be labeled “Replacement Sheet” or “New Sheet” as applicable in the top margin.

2. Marked up copy is optional unless required by the examiner.

  • Must be labeled “Annotated Sheet” if submitted
Image credit: Google Patents

Application Data Sheet (ADS)

An Application Data Sheet (ADS) is required to:

  1. Identify applicants who are not inventors
  2. Set inventorship when an inventors oath is NOT being submitted until later in the prosecution
  3. Set inventorship where there are joint inventors and each joint inventor is executing a declaration that ONLY names that inventor and not all inventors
  4. Make benefit claims under 37 CFR 1.78 and foreign priority claims under 37 CFR 1.55

Common Mistakes found in ADS

1. Signature: Every ADS must be signed by either a registered patent practitioner or the applicant. When a named applicant in the “Applicant Information” section is a juristic entity (e.g., a company), the ADS must be signed by a registered patent attorney. An unsigned ADS will be treated only as a transmittal letter (37 CFR 1.76) with limited information being made of record from it.

2. Domestic benefit: If an applicant wishes to claim the benefit of an earlier-filed U.S. application (e.g., a provisional application), the claim must be made in the “Domestic Benefit/National Stage Information” section of an ADS.

3. File by reference: In an overwhelming majority of filed applications, the “Filing by Reference” section of the ADS should be left BLANK. Overcoming a mistake in completing this section can be particularly costly and time consuming.

4. Typographical errors: Applicants should be sure to carefully check each entry in the ADS for typographical errors. Errors in the spelling of names, prior application numbers, addresses, etc. are not always easy to fix and can cost applicants money, time, and additional paperwork.

Updating the ADS

All changes to the ADS must be properly marked up. Information may be corrected or updated by filing a corrected ADS that contains all sections of the form or only the sections of the form containing changed or updated information. Changes must be shown by underlining for insertions and strike- through or [brackets] for deletions

Each section containing changes or updated information must contain all of the information already of record with the changes shown by markings. If the ADS is submitted after the submission of the application, even if it is the first submission of an ADS, any information being added or deleted relative to the information of record must be indicated by markings

Documents must be properly signed

If you are working with a registered practitioner, the practitioner may sign documents, even if you have not appointed him or her to have power of attorney. If you are not working with a registered practitioner and there is no applicant named on an application data sheet (ADS), all inventors must sign each document/submission.If you are not working with a registered practitioner and there is no applicant named on an ADS, all inventors may appoint one or more of the inventors to prosecute the application on everyone’s behalf:

  • Each inventor must sign the form, even the one being appointed.
  • PTO/AIA/81 may be used.

Signature requirement

  • Handwritten
  • S-signature
    • Name between two single forward slashes
    • Signature must be accompanied by printed/typed name of signer and be easily identifiable
  • Graphic representation
    • For electronically submitted correspondence
    • Graphic representation of handwritten signature or S-signature Multiple Inventors: ALL inventors must sign unless a power of attorney has been granted to one or more of the joint inventors

Post filing procedure

Typical processing timeline

Image credit: USPTO

USPTO Office Action

An office action sets forth the basis for any objections, rejections, and allowability.

Rejections are a normal part of the process. They help define what is patentable. They are often due to existing prior art. The examiner must have a basis to believe someone else may have come up with what you invented before you. Rejections can often be overcome.

Role of the USPTO examiner

  1. Read and understand the application.
  2. Search for prior art.
  3. Evaluate the specification and claim(s).
  4. Respond by office action(s) describing findings.
  5. Hold interviews, as requested.

Power of the interview

Image credit: USPTO

Role of the applicant

  • File a complete application
  • Disclose all known prior art
  • In response to examiner office actions:
    • Explain your position, and/or
    • Make good faith changes to the application

After-final Practice

Even if you receive a final rejection, don’t panic. If you still disagree, you may still have options: Request for Continued Examination (RCE), appeal, after-final response.


A notice of allowance indicates all objections and rejections have been overcome and your application is ready for issuance. In 2021, 62% of examiner disposals were allowances.

Anatomy of a patent

Image credit: USPTO