Understanding the Value of Written Patent Descriptions

Author: Joseph M. Manak|February 22, 2022

To be complete, a patent application must include a specification containing a written description of the invention...
Understanding the Value of Written Patent Descriptions

Understanding the Value of Written Patent Descriptions

To be complete, a patent application must include a specification containing a written description of the invention...

To be complete, a patent application must include a specification containing a written description of the invention. Essentially, inventors must be able to adequately state what it is that they invented.

While inventors are understandably leery of disclosing more than is required, a poorly drafted written description can delay the patent application process or even prevent a patent from issuing. Even after a patent is issued, a written description can lead to litigation challenging whether the specification adequately describes the full breadth of the claimed invention. 

Section 112 Written Description Requirement

To satisfy the written description requirement, a patent specification must describe the claimed invention in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention. 35 U.S.C. 112(a) expressly provides:

(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.

The written description requirement has several policy objectives. As described by the Federal Circuit Court of Appeals in Capon v. Eshhar, 418 F.3d 1349, 1357 (Fed. Cir. 2005), "The ‘written description’ requirement implements the principle that a patent must describe the technology that is sought to be patented; the requirement serves both to satisfy the inventor’s obligation to disclose the technologic knowledge upon which the patent is based, and to demonstrate that the patentee was in possession of the invention that is claimed." The written description requirement also ensures that patentees adequately describe their inventions in their patent specifications in exchange for the right to exclude others from practicing the invention for the duration of the patent’s term.

Evaluating the Adequacy of a Written Description

There is no set test for evaluating the adequacy of a written description. Nonetheless, the relevant inquiry has been almost uniformly characterized as an effort to determine whether one of ordinary skill in the field of the invention would have recognized that the inventor was “in possession” of the invention. In general, possession may be shown in a variety of ways including a description of an actual reduction to practice, or by showing that the invention was "ready for patenting" such as by the disclosure of drawings or structural chemical formulas that show that the invention was complete, or by describing distinguishing identifying characteristics sufficient to show that the applicant was in possession of the claimed invention. 

Possession alone, however, will not satisfy the written description requirement, as Federal Circuit precedent has made clear that more than mere possession of the invention is required. As described by the court in Lockwood v. American Airlines, Inc., 107 F.3d 1565, 1572 (Fed. Cir. 1997), a patentee’s disclosure must also include “descriptive means,” such as words, structures, figures, diagrams, formulas, etc., that “fully set forth” the claimed invention.

Litigation Involving Written Descriptions

Issues involving written patent descriptions often arise in patent infringement litigation. For instance, a question may arise as to whether a specification provides an adequate written description may arise in the context of determining whether an original claim is described sufficiently, whether new or amended claims are supported by the description of the invention in the application as filed; whether a claimed invention is entitled to the benefit of an earlier priority date or effective filing date under 35 U.S.C. 119120,365, or 386; or whether a specification provides support for a claim corresponding to a count in an interference. In any case, compliance with the written description requirement is a question of fact which must be resolved on a case-by-case basis.

Although every written description challenge must be assessed on its own facts, as opposed to the straight application of case precedent, several well-settled principles have emerged that often guide trial courts. Below are a few examples:

  • An invention does not have to be described in ipsis verbis or in haec verba in order to satisfy the description requirement of §112.
  • While an ipsis verbis recitation of the invention is not required and no particular form of disclosure is mandated,  the disclosure must at least “reasonably convey to persons skilled in the art that the inventor had possession of the subject matter in question.”
  • The focus of the description inquiry is on what is claimed. To meet the written description requirement, the specification must describe every element or limitation of the claimed invention. As the Federal Circuit explained in Lockwood, “While the meaning of terms, phrases, or diagrams in a disclosure is to be explained or interpreted from the vantage point of one skilled in the art, all the limitations must appear in the specification. . . . The invention is, for purposes of the written description inquiry, whatever is now claimed.
  • A claimed invention which is no more than an “obvious variant” of that described in the specification is not supported by an adequate written description. As described by the Federal Circuit in Lockwood, while a specification need not describe “the claimed subject matter in exactly the same terms as used in the claims, it must contain an equivalent description of the claimed subject matter. A description which renders obvious the invention . . . is not sufficient.”
  • A patent claim that meets the enablement standard of §112 because the specification teaches how to make and use the claimed invention may nonetheless be held invalid if not supported by an adequate description of the claimed invention.
  • Satisfaction of the description requirement is measured by the understanding of the ordinary skilled artisan as of the filing date of the patent application.
  • It is in general improper to use hindsight to confer an adequate description onto a patent specification where no such description is reasonably or clearly found in the specification in the first instance; i.e., as of the time it was filed.
  • While it is not necessary that every species in a genus be described in order to describe the genus adequately, a description of a species does not always constitute a description of the genus of which it is a part.

Key Takeaway

Written descriptions are often overlooked during the patent application process. However, as highlighted below, they can play a key role in whether the USPTO grants your patent or whether it survives a legal challenge. Working with an experienced intellectual property can help ensure that your patent rights are protected.

If you have questions, please contact us

If you have any questions or if you would like to discuss the matter further, please contact me, Joseph Manak, or the Scarinci Hollenbeck attorney with whom you work, at 201-896-4100.


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AboutJoseph M. Manak

Joseph M. Manak, Esq. is a Patent and Intellectual Property attorney, litigator and trial lawyer.Full Biography

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Understanding the Value of Written Patent Descriptions

Understanding the Value of Written Patent Descriptions
Author: Joseph M. Manak

To be complete, a patent application must include a specification containing a written description of the invention. Essentially, inventors must be able to adequately state what it is that they invented.

While inventors are understandably leery of disclosing more than is required, a poorly drafted written description can delay the patent application process or even prevent a patent from issuing. Even after a patent is issued, a written description can lead to litigation challenging whether the specification adequately describes the full breadth of the claimed invention. 

Section 112 Written Description Requirement

To satisfy the written description requirement, a patent specification must describe the claimed invention in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention. 35 U.S.C. 112(a) expressly provides:

(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.

The written description requirement has several policy objectives. As described by the Federal Circuit Court of Appeals in Capon v. Eshhar, 418 F.3d 1349, 1357 (Fed. Cir. 2005), "The ‘written description’ requirement implements the principle that a patent must describe the technology that is sought to be patented; the requirement serves both to satisfy the inventor’s obligation to disclose the technologic knowledge upon which the patent is based, and to demonstrate that the patentee was in possession of the invention that is claimed." The written description requirement also ensures that patentees adequately describe their inventions in their patent specifications in exchange for the right to exclude others from practicing the invention for the duration of the patent’s term.

Evaluating the Adequacy of a Written Description

There is no set test for evaluating the adequacy of a written description. Nonetheless, the relevant inquiry has been almost uniformly characterized as an effort to determine whether one of ordinary skill in the field of the invention would have recognized that the inventor was “in possession” of the invention. In general, possession may be shown in a variety of ways including a description of an actual reduction to practice, or by showing that the invention was "ready for patenting" such as by the disclosure of drawings or structural chemical formulas that show that the invention was complete, or by describing distinguishing identifying characteristics sufficient to show that the applicant was in possession of the claimed invention. 

Possession alone, however, will not satisfy the written description requirement, as Federal Circuit precedent has made clear that more than mere possession of the invention is required. As described by the court in Lockwood v. American Airlines, Inc., 107 F.3d 1565, 1572 (Fed. Cir. 1997), a patentee’s disclosure must also include “descriptive means,” such as words, structures, figures, diagrams, formulas, etc., that “fully set forth” the claimed invention.

Litigation Involving Written Descriptions

Issues involving written patent descriptions often arise in patent infringement litigation. For instance, a question may arise as to whether a specification provides an adequate written description may arise in the context of determining whether an original claim is described sufficiently, whether new or amended claims are supported by the description of the invention in the application as filed; whether a claimed invention is entitled to the benefit of an earlier priority date or effective filing date under 35 U.S.C. 119120,365, or 386; or whether a specification provides support for a claim corresponding to a count in an interference. In any case, compliance with the written description requirement is a question of fact which must be resolved on a case-by-case basis.

Although every written description challenge must be assessed on its own facts, as opposed to the straight application of case precedent, several well-settled principles have emerged that often guide trial courts. Below are a few examples:

  • An invention does not have to be described in ipsis verbis or in haec verba in order to satisfy the description requirement of §112.
  • While an ipsis verbis recitation of the invention is not required and no particular form of disclosure is mandated,  the disclosure must at least “reasonably convey to persons skilled in the art that the inventor had possession of the subject matter in question.”
  • The focus of the description inquiry is on what is claimed. To meet the written description requirement, the specification must describe every element or limitation of the claimed invention. As the Federal Circuit explained in Lockwood, “While the meaning of terms, phrases, or diagrams in a disclosure is to be explained or interpreted from the vantage point of one skilled in the art, all the limitations must appear in the specification. . . . The invention is, for purposes of the written description inquiry, whatever is now claimed.
  • A claimed invention which is no more than an “obvious variant” of that described in the specification is not supported by an adequate written description. As described by the Federal Circuit in Lockwood, while a specification need not describe “the claimed subject matter in exactly the same terms as used in the claims, it must contain an equivalent description of the claimed subject matter. A description which renders obvious the invention . . . is not sufficient.”
  • A patent claim that meets the enablement standard of §112 because the specification teaches how to make and use the claimed invention may nonetheless be held invalid if not supported by an adequate description of the claimed invention.
  • Satisfaction of the description requirement is measured by the understanding of the ordinary skilled artisan as of the filing date of the patent application.
  • It is in general improper to use hindsight to confer an adequate description onto a patent specification where no such description is reasonably or clearly found in the specification in the first instance; i.e., as of the time it was filed.
  • While it is not necessary that every species in a genus be described in order to describe the genus adequately, a description of a species does not always constitute a description of the genus of which it is a part.

Key Takeaway

Written descriptions are often overlooked during the patent application process. However, as highlighted below, they can play a key role in whether the USPTO grants your patent or whether it survives a legal challenge. Working with an experienced intellectual property can help ensure that your patent rights are protected.

If you have questions, please contact us

If you have any questions or if you would like to discuss the matter further, please contact me, Joseph Manak, or the Scarinci Hollenbeck attorney with whom you work, at 201-896-4100.