PTAB

IPR2021-00062

Assembly Guidance Systems Inc v. Virtek Vision Intl ULC

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1. Case Identification

2. Patent Overview

  • Title: Laser Projection with Flash Alignment
  • Brief Description: The ’734 patent discloses a method for quickly aligning a laser projector with a work surface. The method uses a two-step process: first, a photogrammetry device and a secondary light source identify an approximate 3D pattern of reflective targets on the work surface ("flash" alignment); second, the laser projector uses this approximate pattern to directly scan the targets and calculate their precise location for accurate projection.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 5, 7, and 10-13 are obvious over Keitler in view of Briggs.

  • Prior Art Relied Upon: Keitler (Application # 2014/0160115) and Briggs (WO 2012/033892).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Keitler discloses the core two-step alignment process of the ’734 patent: a first step using a camera to determine an "approximate direction" to targets, followed by a second step where a laser performs a localized search based on that direction to find the "precise registration" of the targets. However, Petitioner contended that Keitler teaches determining approximate angular directions, not the approximate 3D coordinates required by claim 1. To supply this missing element, Petitioner cited Briggs, which explicitly teaches using a photogrammetry system with two cameras and triangulation to find the three-dimensional coordinates of reflective targets.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because both relate to laser tracking and projection systems. Petitioner asserted that substituting Briggs’ method for determining 3D coordinates in place of Keitler’s method for determining angular directions would have been an obvious design choice to improve the precision of the initial alignment step, as both were known measurement techniques for such systems.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination because both references operate in the same technical field, and integrating a known 3D coordinate measurement system (Briggs) into a known two-step alignment framework (Keitler) would yield predictable results.

Ground 2: Claims 1, 2, 5, 7, and 10-13 are obvious over Briggs in view of Bridges.

  • Prior Art Relied Upon: Briggs (WO 2012/033892) and Bridges (Patent 8,040,525).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground presented an alternative invalidity theory. Petitioner argued that Bridges discloses a laser tracker system that performs a two-step alignment process similar to the one taught by Keitler: it uses a locator camera and a secondary light source (LEDs) to determine the "approximate angular direction" of retroreflector targets, and then uses this information to direct the laser beam in a search pattern to determine their absolute distance and precise location. As with the Keitler-based ground, Petitioner argued Bridges teaches determining approximate angular direction, not 3D coordinates. Petitioner asserted that Briggs, which discloses using photogrammetry with one or two cameras to determine either angular directions or precise 3D coordinates, supplies the missing element.
    • Motivation to Combine: Petitioner argued that a POSITA would have been motivated to combine the teachings of Briggs and Bridges to improve the performance of the alignment system. Since Briggs teaches that 3D coordinate measurement is an alternative to angular direction measurement for locating targets, it would have been obvious to implement the more precise 3D coordinate system of Briggs into the two-step framework of Bridges.
    • Expectation of Success: A POSITA would expect this combination to work successfully, as it involved substituting one known type of position measurement (3D coordinates) for another (angular direction) within a conventional laser tracking system architecture.

  • Additional Grounds: Petitioner asserted additional obviousness challenges (Grounds 2 and 4) that built upon the primary combinations. These grounds added the '094 Rueb reference (Application # 2013/0250094), which is related to the challenged ’734 patent, to the Keitler/Briggs and Briggs/Bridges combinations. The '094 Rueb reference was cited primarily to teach limitations found in dependent claims 3-6 and 8-12, such as using a multi-megapixel sensor, a camera with a specific field of view (approx. 75 degrees), a flashing light source, and detecting workpiece drift.

4. Key Claim Construction Positions

  • "photogrammetry device": Petitioner argued this term should be construed as "a device for making reliable measurements by the use of photographs, including digital photographs." This construction is broad enough to encompass camera systems in the prior art that perform measurements but are not explicitly labeled "photogrammetry devices."
  • "identifying a pattern of the reflective targets ... in a three dimensional coordinate system": Petitioner contended this phrase, based on the patent’s specification and file history, should be construed to mean identifying the "approximate locations" of the targets. This construction is central to establishing the patent's two-step "approximate-then-precise" method, which Petitioner alleged was known in the art.
  • "scanning the targets with a laser beam ... as directed by the identified pattern": Following the construction of the previous term, Petitioner argued this phrase should mean "directing the laser beam to the targets based on the approximate three-dimensional coordinate locations" for precise measurement. This links the second step of the claimed method to the approximated result of the first step.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-13 of the ’734 patent as unpatentable under 35 U.S.C. §103.