Failure to Identify Prior Art Disclosure of a Limiting Preamble Dooms IPR Petition

May 27, 2021

Reading Time : 2 min

The petition challenged a patent claiming an apparatus and a method for the automated irrigation of crops. The claimed invention recited sensors that are associated with one or more plants that were being irrigated. In the sole method claim, this sensor element was part of a lengthy preamble. The petitioner challenged the method claim as anticipated by a prior art patent, arguing that to the extent the preamble was limiting, the prior art patent disclosed the preamble. The patent owner argued that the preamble was limiting and that the prior art patent lacked the preamble.

The board agreed with the patent owner, determining first that the preamble was limiting and second that the prior art patent failed to disclose the preamble. The board explained that a preamble is limiting if it either “recites essential structure or steps” or is “necessary to give life, meaning, and vitality” to the claim. To determine whether the limiting preamble test was met, the board turned to the disclosure of the challenged patent. The board found that the challenged patent taught how having sensors associated with specific plants would allow the user to tailor the irrigation and provide numerous benefits. Thus, the board explained, the preamble was “not merely the purpose or intended use of the claimed invention.” Rather, the preamble included essential structure and steps that were needed to give life, meaning and vitality to the claim. The board explained that the body of the claim by itself was not enough “to set out the complete invention.”

The board then found that additional evidence supported its conclusion. First, during prosecution, the sensor limitation was added to the preamble, leading to the claim being allowed. As such, the limitation was specifically used to distinguish the claim from the prior art. Second, the preamble provided antecedent basis for other elements in the body of the claim, including the sensors.

On the merits, the board found that the prior art patent’s sensors were not associated with one or more particular plants. Instead, the sensors were associated with other aspects of crop growing, such as soil type or topography. Because the prior art patent lacked the sensor element, the petitioner had failed to show a reasonable likelihood of prevailing on its unpatentability challenge.

Practice tip:

A preamble, whether long or short, may be limiting if it meets certain tests. Parties disputing the patentability of a claim should pay close attention to a preamble and carefully analyze whether or not it should be construed as limiting. Even when a petitioner argues that a preamble is not limiting, the petitioner is well advised to consider including an alternative ground that assumes the preamble is limiting. The board’s decisions are clear that if a petitioner fails to identify where in the prior art a limitation is disclosed, the petitioner has failed to show a reasonable likelihood that a claim is unpatentable.

E. & J. Gallo Winery v. Vineyard Investigations, IPR2021-00076, Paper 9 (PTAB May 11, 2021)

Share This Insight

Previous Entries

IP Newsflash

February 20, 2026

The Federal Circuit recently addressed whether the PTO must conduct notice‑and‑comment rulemaking before issuing instructions that guide how the Board should exercise discretion at the institution stage of IPRs. The court held that no such rulemaking is required. Instructions to the Board regarding its use of the Director’s delegated discretionary authority not to institute review are merely general statements of policy exempt from notice-and-comment rulemaking.  

...

Read More

IP Newsflash

February 18, 2026

The District Court for the District of Delaware recently invalidated claims directed to a panoramic objective lens for lack of enablement, holding the claims impermissibly recited a single element in means‑plus‑function form. Under § 112, ¶ 6, “[a]n element in a claim for a combination may be expressed as a means or step for performing a specified function….” By its plain terms, the statute permits means‑plus‑function claiming only in the context of a “combination.” In other words, a claim may not consist solely of a single means‑plus‑function element. Claims drafted as a single means are invalid for lack of enablement as a matter of law.

...

Read More

IP Newsflash

February 13, 2026

In an ANDA litigation, the District of Delaware recently denied the defendants’ motion to compel the production of correspondence between the plaintiffs’ testifying expert and a third-party analyst who had performed experiments and provided data used by the testifying expert. The court found that the scope of material sought by the motion was overbroad and disproportionate to the needs of the case.

...

Read More

IP Newsflash

February 12, 2026

In an ANDA litigation, the District of Delaware recently denied the plaintiffs’ motion to strike portions of the defendants’ expert reports and related deposition testimony. Although the defendants’ invalidity contentions did not state the specific theories of invalidity upon which the expert opined, the court found that none of the Pennypack factors supported excluding that expert testimony.

...

Read More

© 2026 Akin Gump Strauss Hauer & Feld LLP. All rights reserved. Attorney advertising. This document is distributed for informational use only; it does not constitute legal advice and should not be used as such. Prior results do not guarantee a similar outcome. Akin is the practicing name of Akin Gump LLP, a New York limited liability partnership authorized and regulated by the Solicitors Regulation Authority under number 267321. A list of the partners is available for inspection at Eighth Floor, Ten Bishops Square, London E1 6EG. For more information about Akin Gump LLP, Akin Gump Strauss Hauer & Feld LLP and other associated entities under which the Akin Gump network operates worldwide, please see our Legal Notices page.