PTAB

IPR2019-00254

Elo Touch Solutions, Inc. v. 3M Innovative Properties Company

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1. Case Identification

2. Patent Overview

  • Title: Touch Screen Sensor
  • Brief Description: The ’381 patent is directed to touch screen sensors that use an electrically conductive micropattern on a transparent substrate, rather than a continuous coating of transparent conducting oxide (TCO). This design purports to allow for better engineering of the sensor’s electrical and optical properties, such as achieving high optical quality with specific conductor trace geometries.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4-8, 10-12, 14-21, and 26-29 are obvious over Binstead in view of 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 taught the basic structure of a capacitive touch screen sensor with a micropattern of conductors on a transparent substrate. However, Binstead did not explicitly disclose the specific narrow conductor trace widths (e.g., 0.5-10 micrometers) or the high open area fractions (OAFs) required by the independent claims. To supply these missing elements, Petitioner asserted that Kumar taught forming micropatterns for electronic sensors with conductive trace widths well within the ranges claimed in the ’381 patent (e.g., lines of 2 micrometers). Further, Petitioner argued that Yoshikawa taught controlling the "aperture ratio" (equivalent to OAF) of a touch panel by adjusting the width and pitch of a metal mesh, disclosing OAFs of 98% which fall within the claimed ranges.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine Binstead with Kumar to improve optical quality and sensor resolution. Finer conductor traces, as taught by Kumar, were known to reduce haze and improve transparency. A POSA would then be motivated to incorporate Yoshikawa's teachings to predictably control the OAF, thereby maintaining high optical transparency while achieving the desired sheet resistance for the sensor. Petitioner contended this was a matter of routine optimization to balance known, competing design parameters.
    • Expectation of Success: The combination was argued to be predictable. A POSA would expect that reducing trace width (per Kumar) and adjusting pitch (per Yoshikawa) in Binstead’s sensor would predictably yield a touch sensor with improved optical properties and the desired electrical performance.

Ground 2: Claims 1, 4-8, 10-12, 14-22, and 26-28 are obvious over Okumura in view of 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 presented Okumura as an alternative primary reference that taught an electrostatic capacitance touch panel using a network of "ultra-fine bands" (≤30µm wide) to overcome the drawbacks of TCO-based sensors. While Okumura suggested fine conductors, Petitioner relied on Chen to explicitly teach conductor trace widths on the order of 1.5µm for touch panel LCDs, squarely meeting the limitations of the ’381 patent claims. As in the first ground, Yoshikawa was again cited for its teachings on controlling the "aperture ratio" (OAF) by modifying conductor width and pitch to achieve high transparency (e.g., 98%).
    • Motivation to Combine: Petitioner argued a POSA would have been motivated to modify Okumura’s sensor by adopting the even finer trace widths taught by Chen to gain known advantages, such as lower haze, higher light transmission, and improved spatial resolution. A POSA would then apply Yoshikawa's principles to optimize the micropattern's OAF and sheet resistance, constituting a mere substitution of known features to achieve a predictable result.
    • Expectation of Success: A POSA would have had a high expectation of success in combining these references. The petition argued that modifying Okumura's micropattern with Chen's finer conductors and Yoshikawa's OAF control methods involved applying well-understood design principles to achieve predictable improvements in optical and electrical performance.

  • Additional Grounds: Petitioner asserted additional obviousness challenges that built upon these two core combinations.

    • Takayama (Patent 7,956,287) was added to teach specific haze (<5%) and transmission (>85%) values.
    • Mackey (Patent 7,129,935) was added to teach the use of electrically isolated "dummy deposits" to maintain optical uniformity across a non-uniform micropattern.
    • Kang (Patent 6,445,426) was added to teach the introduction of "selective breaks" in a conductive mesh to control or vary sheet resistance in specific regions.
    • Giraud (Patent 5,846,854) was added to teach "micro-replication"—a specific method of fabricating the micropattern by filling fine grooves in a substrate.

4. Relief Requested

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