PTAB

IPR2019-00254

Elo Touch Solutions Inc v. 3M Innovative Properties Co

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: TOUCH SCREEN SENSOR
  • Brief Description: The ’381 patent describes a touch screen sensor using an electrically conductive micropattern, typically metal, on a transparent substrate. The technology purports to offer improved control over electrical and optical properties compared to conventional sensors that rely on continuous coatings of transparent conducting oxide (TCO), by specifying conductor trace widths and "open area fractions."

3. Grounds for Unpatentability

Ground 1: Claims 1, 4-8, 10-12, 14-21, and 26-29 are obvious over Binstead, Yoshikawa, and Kumar.

  • Prior Art Relied Upon: Binstead (Application # 2006/0278444), Yoshikawa (Japanese Patent Application Publication No. JP 2004-192093), and Kumar (Patent 5,512,131).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Binstead disclosed the foundational touch screen sensor, comprising a transparent substrate with a micropattern of conductive wires for touch sensing. However, Binstead’s disclosure of conductor width (e.g., less than 25 microns) was broader than the claimed ranges. Kumar was introduced to teach the specific, narrower conductor trace widths recited in the independent claims (e.g., 0.5 to 10 micrometers), as Kumar explicitly disclosed forming micron and sub-micron sized features for microelectronic devices and sensors. Yoshikawa was introduced to teach the claimed ranges for "open area fraction" (OAF), which it referred to as "aperture ratio." Yoshikawa taught controlling this ratio by adjusting conductor width and pitch to achieve high transparency (e.g., 98%), meeting the limitations of the independent claims.
    • Motivation to Combine: A POSITA would combine Binstead’s sensor with Kumar’s teachings on narrow trace widths to predictably improve the sensor’s optical quality (e.g., lower haze, higher transparency) and increase spatial resolution. A POSITA would have been further motivated to incorporate Yoshikawa's method of controlling the aperture ratio to predictably achieve a desired high transparency while using the finer conductors taught by Kumar. Petitioner asserted this combination represented a routine optimization of known design parameters to achieve predictable results.
    • Expectation of Success: A POSITA would have had a high expectation of success because the references operated in the same field, and Yoshikawa provided an explicit roadmap for controlling transparency by modifying conductor width and pitch. The combination involved applying known techniques to achieve well-understood benefits.

Ground 2: Claims 1, 4-8, 10-12, 14-22, and 26-28 are obvious over Okumura, Yoshikawa, and Chen.

  • Prior Art Relied Upon: Okumura (Japanese Patent Application Publication No. JP 2006-344163), Yoshikawa (Japanese Patent Application Publication No. JP 2004-192093), and Chen (Application # 2007/0018076).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner alleged that Okumura served as the primary reference, disclosing a touch panel with a conductive micropattern of "ultra-fine bands" (30µm or less) on a transparent substrate as an alternative to ITO-based sensors. To the extent Okumura did not explicitly disclose the narrowest claimed trace widths, Chen was cited for its teaching of conductive micropatterns with trace widths on the order of 1.5µm for use in touch panel LCDs. As in the first ground, Yoshikawa was relied upon to teach the claimed OAF ranges and the methodology for achieving them by controlling the "aperture ratio" of the conductive mesh.
    • Motivation to Combine: A POSITA would combine the references as a matter of routine design and optimization. It would have been obvious to modify Okumura’s sensor by implementing the narrower, well-known conductor widths taught by Chen to improve optical properties and sensitivity. In doing so, a POSITA would apply Yoshikawa’s teachings on controlling width and pitch to maintain a high OAF and thus high transparency, a known desirable characteristic for touch screens.
    • Expectation of Success: The combination was presented as a mere substitution of known elements to achieve predictable results. Chen taught that its fine-trace sensor arrays could be formed using well-known photolithographic steps, ensuring a high likelihood of success in applying its teachings to Okumura’s base sensor design.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on the primary combinations above in further view of other references. These included Takayama (for teaching specific haze and transmission values), Mackey (for teaching electrically isolated "dummy" conductor deposits to improve optical uniformity), Giraud (for teaching a "micro-replication" fabrication process), and Kang (for teaching "selective breaks" in a mesh to control sheet resistance).

4. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner’s arguments centered on the contention that the relationships between conductor width, pitch, open area fraction (OAF), haze, and light transmission were well-understood principles in the art before the ’381 patent’s priority date. Petitioner argued that optimizing these known variables to achieve desired optical and electrical properties was a matter of routine design choice for a POSITA, not an inventive step. This rendered the claimed ranges for trace width and OAF obvious selections from a known continuum of design possibilities.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-30 of the ’381 patent as unpatentable.