Cypress Semiconductor Corp v. Neodron Ltd

1. Case Identification

• Case #: IPR2021-01322
• Patent #: 9,024,790
• Filed: July 29, 2021
• Petitioner(s): Cypress Semiconductor Corp.
• Patent Owner(s): Neodron Ltd.
• Challenged Claims: 1-24

2. Patent Overview

• Title: Capacitive Keyboard with Non-Locking Reduced Keying Ambiguity
• Brief Description: The ’790 patent describes a method for determining a user's intended key selection on a capacitive keyboard when their finger overlaps multiple keys. The system identifies the key with the maximum signal strength as the active key and applies a bias to the analysis to prevent undesirable rapid switching ("dithering") to another key unless the new key's signal exceeds the active key's signal by a certain amount.

3. Grounds for Unpatentability

Ground 1: Anticipation/Obviousness over Jahier - Claims 1-2, 5-8, and 18-24 are anticipated by or obvious over Jahier.

• Prior Art Relied Upon: Jahier (Patent 5,525,980).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Jahier discloses every limitation of the independent claims. Jahier describes a capacitive keyboard that compares capacitance values against thresholds to determine a "preselected" key (the first active key). To switch to a new preselected key (the second active key), Jahier requires the new key's signal to not only exceed the current key's signal but also surpass a "High Threshold." This requirement, Petitioner contended, constitutes a "bias" in favor of the first key. The system is non-locking because a new key can become preselected if its signal is strong enough, satisfying the core functionality of the ’790 patent.
  • Motivation to Combine (for §103 grounds): As an alternative to anticipation, Petitioner argued that any minor differences would have been obvious modifications. For instance, if Jahier's "High Threshold" requirement was not seen as a direct equivalent to the claimed bias, a person of ordinary skill in the art (POSITA) would have been motivated to add such a bias to improve stability and prevent dithering, a known problem in the art.
  • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success in applying a signal bias, as it was a well-understood technique for filtering signal noise and stabilizing outputs in sensor systems.

Ground 2: Obviousness over Jahier and Senk - Claims 4, 10-11, and 16-17 are obvious over Jahier in view of Senk.

• Prior Art Relied Upon: Jahier (Patent 5,525,980) and Senk (Patent 5,760,715).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addresses dependent claims that specify the biasing mechanism as either increasing the active key's signal or decreasing the signals of non-active keys. Petitioner argued that Jahier provides the base system for biased key selection, while Senk explicitly teaches modifying key signal values by adjusting their stored "no key touch" reference levels. Senk’s method could be used to suppress signals from certain keys (decreasing their values) or, by logical extension, to enhance the signal of a selected key (increasing its value).
  • Motivation to Combine: A POSITA would combine Jahier and Senk to implement a more robust biasing scheme. Senk is directed to the same problem of resolving ambiguity in capacitive touch systems. A POSITA would see Senk’s technique of adjusting reference values as a direct and effective way to implement the biasing concept in Jahier, leading to a more stable system that is less prone to unintended key switches.
  • Expectation of Success: The combination was expected to succeed because Senk’s signal adjustment method is directly applicable to the capacitance measurements and comparisons performed in Jahier's system.

Ground 3: Obviousness over Jahier and QT60161 - Claims 5, 12, and 18 are obvious over Jahier in view of QT60161.

• Prior Art Relied Upon: Jahier (Patent 5,525,980) and QT60161 (a datasheet for a Quantum Research Group sensor IC).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground challenges claims requiring an "associated counter" for each key. Petitioner asserted that the QT60161 datasheet discloses a "detection integrator" counter for its touch controller IC, which increments with each detection sample until a user-defined limit is reached to confirm a key press. This maps directly to the claimed counter. The target count value in QT60161 is programmable on a per-key basis, allowing the system to be biased by setting a lower count threshold for a currently active key.
  • Motivation to Combine: A POSITA would be motivated to implement the conceptual method of Jahier using a commercially available, off-the-shelf component like the controller described in QT60161. The datasheet provides a concrete, well-documented solution for functions like filtering signal noise and confirming touches over time, which Jahier's system requires.
  • Expectation of Success: A POSITA would have a high expectation of success, as this involves integrating a standard industry component to perform its intended function within a compatible system.
• Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) for claims 3, 9, and 15 over Jahier in view of West (Patent 5,831,597), which teaches adding a "guard ring" to a capacitive keypad to prevent erroneous touch indications.

4. Key Claim Construction Positions

• "control logic ... being biased in favor of the first key": Petitioner adopted a construction from a prior litigation, arguing this means the analysis is "biased or skewed in favor of, but not locked to the previously determined first active key." This construction was central to distinguishing the invention from prior art "locking" systems and aligning it with the teachings of Jahier.
• "control logic ... configured to...": For this means-plus-function term, Petitioner argued the prior art disclosed the corresponding structure from the ’790 patent’s specification (e.g., a microprocessor executing the algorithm of Figs. 5A/5B), including logic for comparing sensor values to a threshold and a counter.

5. Key Technical Contentions (Beyond Claim Construction)

• Priority Date Challenge: Petitioner contended that the ’790 patent was not entitled to its claimed 2002 priority date. The core "non-locking" feature, which relies on biasing the key selection analysis, was allegedly first disclosed in a provisional application filed in December 2005. This later priority date was crucial for establishing that the asserted prior art references (published 1996-2002) qualify as prior art under 35 U.S.C. §102.

6. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) based on Fintiv, asserting that the parallel ITC proceeding was in its earliest stages and that Petitioner would stipulate not to pursue the same invalidity grounds in the ITC if the IPR was instituted.
• Petitioner also argued against denial under §325(d), stating that while the grounds were substantively identical to a previously filed IPR, that prior case was dismissed after institution due to settlement. As the Board never reached a final determination on the merits, denial would be inappropriate.

7. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-24 of the ’790 patent as unpatentable.