PTAB

IPR2022-01489

Platinum Optics Technology Inc v. Viavi Solutions Inc

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Optical Device
  • Brief Description: The ’794 patent relates to optical interference filters, specifically near-infrared band-pass filters (BPFs). The technology involves using alternating layers of materials with different refractive indices, including a first set of layers comprising silicon and hydrogen, and a second set comprising oxygen, to achieve desired filtering properties.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-19 under §102 over Hendrix

  • Prior Art Relied Upon: Hendrix (Application # 2014/0014838).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the ’794 patent is not entitled to its claimed priority date before March 1, 2019. The reasoning asserted was that the original applications disclosed a specific "improved" hydrogenated silicon (Si:H) material with a low extinction coefficient for high-refractive-index layers, while the challenged claims were broadened to encompass any material containing silicon and hydrogen. Because this alleged broadening lacks written description support in the parent applications, Petitioner contended Hendrix—a publication of a parent application—qualifies as prior art under 35 U.S.C. §102. Petitioner then mapped Hendrix's disclosure element-for-element to the challenged claims. For claim 1, Hendrix was alleged to disclose a near-infrared BPF with a first set of layers of hydrogenated silicon (Si:H) and a second set of layers of an oxide (e.g., SiO2), with an antireflective (AR) coating (a third set of layers containing oxygen) on the opposite side of the substrate, anticipating all limitations.
    • Key Aspects: The central thesis of this ground is the loss of priority date, which recharacterizes a parent application's publication as invalidating prior art.

Ground 2: Obviousness of Claims 1-3 and 6 over Lairson in view of Erdogan or Tsai-133

  • Prior Art Relied Upon: Lairson (a 2007 SPIE proceeding), Erdogan (Patent 6,809,859), and Tsai-133 (Patent 5,398,133).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted Lairson taught using alternating layers of Si:H (a material with silicon and hydrogen) and SiO2 (a material with silicon and oxygen) to form "short wave pass stacks." This combination was argued to disclose the first and second sets of layers on one side of a substrate as required by claim 1. However, Lairson only described a short-pass filter, not the complete BPF of claim 1, which typically requires both a short-pass and a long-pass filter. Erdogan and Tsai-133 were cited for teaching the conventional, textbook method of constructing a BPF by placing a short-pass filter on one side of a substrate and a long-pass filter on the other.
    • Motivation to Combine: A POSITA would combine these references to create a complete BPF. Lairson's disclosure of a short-pass stack for BPF designs would have suggested to a POSITA that the well-known technique of adding a complementary long-pass stack (as taught by Erdogan and Tsai-133) on the opposite side of the substrate was intended. Using the same materials (Si:H/SiO2) for both stacks would simplify manufacturing.
    • Expectation of Success: Success was expected because combining a short-pass and long-pass filter was a fundamental and predictable technique for creating a BPF, and the materials disclosed in Lairson were known to be suitable for such applications.

Ground 3: Obviousness of Claims 1-3 and 6 over Yoda in view of Tsai-133

  • Prior Art Relied Upon: Yoda (a 2004 Applied Optics journal article) and Tsai-133 (Patent 5,398,133).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner contended that Yoda disclosed a near-infrared BPF fabricated on a substrate with alternating layers of amorphous Si:H (a-Si:H) and SiO2. This structure was argued to teach every limitation of claim 1 except for the "third set of layers on the second side" of the substrate. Tsai-133 was introduced for its teaching of applying an AR coating on the opposite side of a substrate from a filter stack to improve light transmittance by reducing reflections.
    • Motivation to Combine: A POSITA would combine Yoda's filter with Tsai-133's teaching of an AR coating to achieve the known and desirable benefit of improved filter performance. Adding an AR coating to an optical filter was a conventional technique to suppress unwanted reflections and increase transmittance.
    • Expectation of Success: A POSITA would have reasonably expected to succeed in applying an AR coating to Yoda's filter. The design principles were well-understood, the results were predictable and could be modeled with software, and using the same materials (a-Si:H/SiO2) for the AR coating would simplify fabrication.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations using Pilgrim (Application # 2012/0224061) to teach specific wavelength shift performance and Bamji (Patent 6,323,942) to provide motivation for use in a 3D image sensing system.

4. Key Claim Construction Positions

  • "whether the third set of layers includes oxygen" (Claim 1): Petitioner argued this phrase should be construed to mean that a third set of layers is present on the second side of the substrate, and those layers may or may not include oxygen. This interpretation supports the obviousness argument that it would have been logical to add a conventional AR coating (which typically contains oxygen, e.g., SiO2) to the backside of the substrate taught by the primary references.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be improper. It asserted that this petition presents different grounds than a previously filed petition by another party, the challenged claims do not fully overlap, and Petitioner in this proceeding is not the petitioner in the earlier-filed case. Further, Petitioner contended that no trial date was set in co-pending litigation, and this petition would not adversely impact Board resources.

6. Relief Requested

  • Petitioner requests the institution of an inter partes review and cancellation of claims 1-19 of the ’794 patent as unpatentable.