PTAB

IPR2015-00040

MasterImage 3D Inc v. RealD Inc

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1. Case Identification

2. Patent Overview

  • Title: Polarization Conversion Systems For Stereoscopic Projection
  • Brief Description: The ’934 patent discloses a polarization conversion system and method for projecting brighter three-dimensional images. The system utilizes a polarizing beam splitter (PBS) to separate light into two paths, a rotator to align the polarization of one path with the other, and a polarization switch to alternate the polarization for stereoscopic viewing.

3. Grounds for Unpatentability

Ground 1: Obviousness over Silverstein - Claims 1, 2, 6-11, and 18-20 are obvious over Silverstein

  • Prior Art Relied Upon: Silverstein (Patent 7,559,653).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Silverstein teaches all elements of a stereoscopic projection system designed to enhance brightness. Silverstein’s polarizer (96) functions as the claimed PBS, splitting light into separate left (L) and right (R) channels with orthogonal polarizations. Its half-wave plate (72) serves as the claimed polarization rotator, and its switchable polarization rotating element (70) functions as the claimed polarization switch subsystem. A mirror (98) acts as a reflector to direct the second light path toward the same location as the first.
    • Motivation to Combine: As a single-reference ground, the argument focused on inherent teachings. Petitioner contended it would have been obvious to a person of ordinary skill in the art (POSITA) to place Silverstein’s half-wave plate (72) in only one of the two light channels. This modification would align the polarization states of both channels before they reach the switchable element (70), a necessary step for the switch to operate correctly and achieve the known goal of increasing image brightness.
    • Expectation of Success: The expectation of success was argued to be high, as this involved a simple, predictable modification within a single disclosed system to achieve its stated objective of brightness enhancement.

Ground 2: Obviousness over Silverstein and Stupp - Claims 3-5 and 12-17 are obvious over Silverstein in view of Stupp

  • Prior Art Relied Upon: Silverstein (Patent 7,559,653) and Stupp (a 1999 book titled "Projection Displays").
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the Silverstein reference to address the "lens pair" and "telephoto lens pair" limitations in the dependent claims. Petitioner argued that while Silverstein discloses a generic "projection lens" (62), a POSITA would have understood this to be a multi-element lens assembly. Stupp was introduced as evidence of what a POSITA would consider a typical, high-quality projection lens, specifically showing a multi-panel LCD projection lens that functions as a reversed telephoto lens pair.
    • Motivation to Combine: A POSITA would combine the teachings by implementing a conventional multi-element projection lens, as shown in Stupp, within the Silverstein system. The motivation was straightforward: to improve the optical performance and image quality of the projector, a common design goal achieved by using well-known, advanced lens assemblies instead of a simplistic single lens.
    • Expectation of Success: Success was expected, as this modification involved substituting a known, superior component (a multi-element telephoto lens assembly from Stupp) for a functionally equivalent but less-defined component (the "projection lens" in Silverstein) to achieve a predictable improvement in performance.

Ground 3: Obviousness over Lipton and Tani - Claims 1, 2, 6, 7, 10, 11, and 18-20 are obvious over Lipton in view of Tani

  • Prior Art Relied Upon: Lipton (Patent 4,792,850) and Tani (Patent 6,190,013).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued this combination taught the claimed invention by merging an efficient polarization conversion front-end (from Tani) with a stereoscopic modulation system (from Lipton). Tani discloses a PBS system that uses prisms and a half-wave plate to efficiently convert unpolarized light into a single, uniform polarization state with minimal light loss. Lipton teaches a complete stereoscopic system that uses a "push-pull modulator" (the claimed polarization switch) placed after a projector lens to alternate the polarization of light for 3D viewing. However, Lipton’s system begins with an inefficient absorptive linear polarizer, which discards more than half of the initial light.
    • Motivation to Combine: A POSITA would have been motivated to replace Lipton's inefficient linear polarizer with Tani's highly efficient polarization conversion system. The explicit motivation was to solve the well-known problem of brightness loss in stereoscopic projection by recapturing light that Lipton's system wastes, thereby creating a significantly brighter image.
    • Expectation of Success: A high expectation of success was argued because Tani's system was designed to output a bright, uniformly polarized beam, which is the ideal input for Lipton's polarization modulator. The combination represented the integration of two complementary systems to achieve a known objective.
  • Additional Grounds: Petitioner asserted additional obviousness challenges based on the Lipton and Tani combination, further adding Stupp for lens teachings (Ground 5), Applicant Admitted Prior Art for wire grid layers (Grounds 4, 6), and Wentz (Patent 4,515,441) for multi-dielectric layers (Ground 7).

4. Key Claim Construction Positions

  • "polarization beam splitter": Petitioner proposed this term be construed as "a device that creates primary path and secondary path beams of light energy by directing light of one polarization state along the primary path and light of another polarization state along a secondary path." This construction was central to mapping prior art like Silverstein’s polarizer and Tani’s prism assembly to the claims.
  • "polarization switch panel" / "switch subsystem": Petitioner proposed these terms be construed as "a device that receives light energy and outputs the light energy in at least two alternating states of polarization." This construction was used to argue that elements like Silverstein's rotating element (70) and Lipton's push-pull modulator met the claim limitations.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of Patent 8,220,934 as unpatentable.