Viken Detection Corp v. American Science & Engineering Inc

1. Case Identification

• Case #: IPR2021-01585
• Patent #: 7,400,701
• Filed: September 30, 2021
• Petitioner(s): Viken Detection Corporation
• Patent Owner(s): American Science and Engineering, Inc.
• Challenged Claims: 1-13

2. Patent Overview

• Title: Multi-Source X-Ray Inspection System
• Brief Description: The ’701 patent relates to multi-source x-ray inspection systems that use flying spot backscatter technology to detect contraband in objects like cargo containers. The invention purports to solve the "cross-talk" interference problem that arises from using multiple, closely-spaced radiation sources by temporally sequencing the operation of coplanar pencil beams.

3. Grounds for Unpatentability

Ground 1: Anticipation over Seppi - Claims 1-4 and 10-13 are anticipated by Seppi

• Prior Art Relied Upon: Seppi (Patent 7,103,137 or Patent 7,672,422).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Seppi discloses every limitation of the challenged independent claims. Seppi teaches an inspection system with multiple x-ray sources (e.g., 16a-16f) on a semi-circular rail that produce pencil beams to scan an object. Petitioner asserted that pairs of these sources (e.g., 16a and 16e) are arranged to produce beams that are both "substantially coplanar" (on the same plane "P") and "substantially perpendicular" to each other. Crucially, Petitioner contended that Seppi discloses the "temporally interspersed" limitation by teaching that the "operation of the sources...is cycled" so that "only one source is on at a time" to simplify signal analysis and avoid cross-talk. Seppi also discloses a detector array for scattered radiation and a processor to create an image based solely on that signal, thus meeting all limitations of independent claims 1 and 11.

Ground 2: Obviousness over Chalmers and Seppi - Claims 1-6 and 10-13 are obvious over Chalmers in view of Seppi

• Prior Art Relied Upon: Chalmers (Patent 6,459,764) and Seppi (Patent 7,103,137).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Chalmers is a strong primary reference, teaching a multi-source inspection system with a first, substantially horizontal pencil beam and a second, substantially vertical pencil beam, making the beams substantially perpendicular. However, Chalmers does not explicitly teach that the beams are coplanar or temporally interspersed. Petitioner argued these missing elements are supplied by Seppi.
  • Motivation to Combine: A POSITA would combine Chalmers with Seppi to create a more compact and efficient system. The ’701 patent itself acknowledges that physically separating sources to avoid cross-talk leads to undesirably large systems. Seppi explicitly teaches using a coplanar arrangement of sources and temporally interspersing their operation to solve this exact problem. Therefore, a POSITA would have been motivated to apply Seppi's solution for compact design and cross-talk avoidance to the perpendicular beam arrangement of Chalmers.
  • Expectation of Success: Petitioner asserted that combining these known techniques from analogous art to achieve the predictable benefits of a smaller footprint and clearer imaging would have been a straightforward design choice with a high expectation of success.

Ground 3: Obviousness over Seppi and Grodzins 761 - Claims 7-9 are obvious over Seppi in view of Grodzins 761

• Prior Art Relied Upon: Seppi (Patent 7,103,137) and Grodzins 761 (Patent 6,459,761).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground focused on dependent claims 7-9, which recite specific temporal characteristics: operation in temporal periods offset by a "fixed phase relationship" (claim 7), characterized by a "duty cycle" (claim 8), where the phase relationship is equal to 2π times the duty cycle (claim 9). Petitioner argued that while Seppi teaches cycling sources one at a time, it does not explicitly disclose these mathematical relationships.
  • Motivation to Combine: A POSITA implementing Seppi's temporal cycling would find it obvious to use a fixed phase relationship, as it is the simplest and most reliable way to prevent signal overlap. Grodzins 761 was cited as explicitly teaching this solution, disclosing the interleaving of scanning pencil beams with a fixed phase offset (e.g., 90°) to "completely eliminate that cross talk." A POSITA would have looked to Grodzins 761 to implement a robust temporal sequencing protocol in Seppi's system. The duty cycle and phase relationship limitations of claims 8 and 9 were argued to be an inherent and obvious mathematical consequence of any such evenly-divided, sequential operation.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including claims 5-6 over Seppi and Chalmers, and claims 7-9 over Chalmers, Seppi, and Grodzins 761, relying on similar motivations to combine existing technologies.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d), contending that the primary prior art references, Seppi and Chalmers, are new and were not considered during the original prosecution. Petitioner asserted that these references are materially different from the art evaluated by the Examiner because they disclose the specific combination of features—coplanar, perpendicular, and temporally interspersed pencil beams—that the Examiner identified in the Reasons for Allowance as being absent from the prior art of record.
• Petitioner also argued against discretionary denial under 35 U.S.C. §314(a), stating that although a claim of infringement of the ’701 patent was previously asserted in a district court case, the complaint was amended to remove the ’701 patent. Consequently, Petitioner asserted there is no parallel proceeding that would justify denial.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-13 of Patent 7,400,701 as unpatentable.