A “written description” is one of the many requirements for obtaining a patent. The written description requirement is contained in the Patent Act which states that the “specification shall contain a written description of the invention in such full, clear, concise, and exact terms as to enable any person skilled in the art . . . to make and use the same.” See 35 U.S.C. 112(a). This requirement is separate and distinct from other requirements of patentability. Essentially, the written description requirement implements the Patent Act’s requirement that a person or entity seeking a patent must describe the technology that is sought to be patented. According to case law, the written description requirement serves several goals including:

• Satisfies the inventor’s obligation to disclose the technologic knowledge upon which the patent is based
• Demonstrates that the patentee was in possession of the invention that is claimed
• Promotes the progress of the useful arts by ensuring 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

Written description patent invalidity is most often found in cases of continuation or continuation-in-part patent applications where the earlier-filed application fails to describe the invention contained in the later-filed application. A case that provides a pretty clear example is Research Corp. Technologies v. Microsoft Corp., 627 F.3d 859 (Fed. Cir. 2010). The relevant earlier-filed patent application had these claims related to a “blue noise mask” use for halftoning printer and computer screen images:

• A method for the halftoning of gray scale images by utilizing a pixel-by-pixel comparison of the image against a blue noise mask in which the blue noise mask is comprised of a random non-deterministic, non-white noise single valued function which is designed to produce visually pleasing dot profiles when thresholded at any level of said gray scale images.
• The method of claim 1, wherein said blue noise mask is used to halftone a color image.

The subsequently-filed patent application contained these claims related to a “blue noise dot profile” technique:

• The machine of claim 1, wherein substantially all of said number of dot profiles have a power spectrum substantially characteristic of a blue noise power spectrum for the level at which such a dot profile is produced.
• The computer readable memory device of claim 57, wherein said halftoning mask is designed to produce substantially all visually pleasing dot profiles when thresholded at a number of levels.

Based on an examination of the facts presented, the court concluded that a “blue noise mask” is different from a “blue noise dot profile.” The court noted that the relevant inventors had testified that they were in possession of only a blue noise mask at the time of filing the original patent applications. Further, one of the inventors admitted that the earlier-filed applications did not describe any masks other than a blue noise mask. The court held that the earlier-filed application did not describe the blue noise dot profile invention. As such, Claims 4 and 63 of the later-filed application were not entitled to claim the priority date of the earlier-filed patent application.

A challenge based on the written description requirement can also be made in cases NOT involving a continuation patent. There are cases where the patent examiner will reject a patent claim based on a failure of written description. As a practical matter, amending the patent claim or claims might be sufficient to overcome the objection. For more information or if you have questions about applying for a patent, contact the patent lawyers at Revision Legal at 231-714-0100.

The “Possession” Standard Explained

The cornerstone of the written description analysis is whether the specification demonstrates that the inventor was “in possession” of the claimed invention as of the filing date. The Federal Circuit articulated this standard clearly in Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (en banc), holding that the written description requirement is a distinct statutory requirement separate from the enablement requirement, even though both appear in 35 U.S.C. § 112(a).

What does “possession” mean in this context? It means that the specification must describe the invention in sufficient detail that a person of ordinary skill in the art would recognize that the inventor had actually invented what is later claimed. Broad genus claims — claims that encompass a large category of compounds, devices, or methods — are especially vulnerable to written description rejections because inventors sometimes claim more than what they actually invented. In pharmaceutical and biotech patents, this issue arises frequently when a specification discloses a handful of compounds but the claims are written to cover an entire genus of structurally related compounds.

Written Description vs. Enablement: A Critical Distinction

Many inventors and even some practitioners conflate the written description requirement with the enablement requirement. They are related but distinct. Enablement, governed by 35 U.S.C. § 112(a), requires that the specification teach a person of ordinary skill in the art how to make and use the full scope of the claimed invention without undue experimentation. Written description requires that the specification demonstrate that the inventor actually possessed the invention at the time of filing.

The practical difference is this: a specification could theoretically teach someone how to make an invention (enablement) without proving that the named inventor actually made or conceived of it (written description). Conversely, a specification might describe an invention the inventor actually made without fully enabling a skilled artisan to replicate it. Both requirements must be independently satisfied.

Common Scenarios Where Written Description Issues Arise

Written description problems most commonly arise in the following contexts:

• Continuation and continuation-in-part applications — As illustrated by the Research Corp. case above, when a later application tries to claim priority from an earlier application, the earlier application must contain a written description of the later-claimed invention. If it does not, the later claims cannot benefit from the earlier filing date and may be invalidated by intervening prior art.
• Claim amendments during prosecution — When an applicant amends claims during examination to overcome a rejection, the amended claims must still find written description support in the original specification. If amended claims introduce new matter not present in the original specification, the examiner will issue a new matter rejection under 35 U.S.C. § 132.
• Biotechnology and pharmaceutical patents — Courts apply a heightened written description standard in this field because the relationship between structure and function is often unpredictable. Claiming an entire genus based on minimal representative examples may fail if the specification does not demonstrate possession of the full scope of what is claimed.
• Software and computer-implemented inventions — Functional claim language in software patents (e.g., “means for performing” or “configured to”) must be supported by sufficient structural description in the specification. Vague or purely result-oriented language may not satisfy the written description requirement.

Overcoming a Written Description Rejection

When the USPTO issues a written description rejection under Section 112(a), applicants have several options:

• Amend the claims to narrow them so that each limitation finds explicit support in the original specification. This is often the most practical solution when the examiner’s concern is that the claims are broader than what the specification describes.
• Argue that the specification supports the claims by pointing to specific passages, figures, or examples that, properly read, describe the claimed invention. Expert declarations from individuals of ordinary skill in the art can be filed to support this argument.
• File a continuation-in-part application to add new matter to the specification, with the understanding that the new claims will have a later effective filing date. This approach sacrifices priority date but may preserve broader claim coverage.

Addressing written description problems proactively — before filing — is always preferable to remedying them during prosecution or, worse, during litigation. A thorough review of the specification against the claims before filing can prevent costly delays and claim narrowing down the road. Contact the patent lawyers at Revision Legal at 231-714-0100 to discuss how to draft specifications that satisfy the written description requirement.