Intellectual Property > IP Newsflash > Failure to Identify Prior Art Disclosure of a Limiting Preamble Dooms IPR Petition
27 May '21

The Patent Trial and Appeal Board denied institution of a petition for inter partes review (IPR), in part because an allegedly anticipatory prior art patent lacked an element of what the board determined was a limiting preamble.

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)