Samsung Electronics Co Ltd v. NuCurrent Inc

1. Case Identification

• Case #: IPR2019-00860
• Patent #: 8,680,960
• Filed: March 22, 2019
• Petitioner(s): Samsung Electronics Co., Ltd.
• Patent Owner(s): NuCurrent, Inc.
• Challenged Claims: 1-8, 10, 12-13, 15-22, and 24-30

2. Patent Overview

• Title: Multi-layer-multi-turn structure for high efficiency inductors
• Brief Description: The ’960 patent discloses a multi-layer inductor for use in electric circuits, particularly those operating in the radio frequency range. The structure comprises multiple conductor layers separated by insulator layers, configured to reduce resistance loss and improve efficiency.

3. Grounds for Unpatentability

Ground 1: Obviousness over Partovi - Claims 1-4, 10, 15-17, 19, 21, 22, 24-27 are obvious over Partovi.

• Prior Art Relied Upon: Partovi (Application # 2009/0096413).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Partovi teaches every limitation of the challenged claims. Partovi discloses an inductive power transfer system using a primary coil inductor (Fig. 2) and separately discloses that such coils can be implemented as a multi-layer structure using stacked PCB layers to achieve higher flux densities (Fig. 18). Petitioner asserted that Partovi's multi-layer coil 356 explicitly shows a "first conductor layer" and a "second conductor layer" (layers 357), which are "separate" and thus have an "insulator layer" between them. These separate PCB layers are connected by a "via or contact" (connector 358). The remaining limitations of independent claim 1, concerning the generation of magnetic flux and inductance, were argued to be inherent properties of any functional inductor, as admitted by the ’960 patent and disclosed by Partovi. Dependent claims were mapped to Partovi’s disclosures of operating frequency (>1 MHz), use of copper (a thermally conductive material), and connection via a "via."
  • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would have understood that the multi-layer coil structure of Partovi's Figure 18 was an implementation applicable to the primary coil of Figure 2. Alternatively, a POSITA would combine these teachings to achieve Partovi’s stated objectives of creating a compact design with high flux density and efficient power transfer, as multi-layer coils were known to provide these benefits.
  • Expectation of Success: A POSITA would have a high expectation of success because implementing the inductor as a multi-layer PCB coil was a known technique for achieving predictable improvements in compactness and performance.

Ground 2: Obviousness over Partovi and Tseng - Claims 5-7 and 13 are obvious over Partovi in view of Tseng.

• Prior Art Relied Upon: Partovi (Application # 2009/0096413) and Tseng (Patent 9,912,173).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims reciting specific conductor thicknesses relative to skin depth (claims 5-7) and a minimum inductor quality factor (Q factor) of 5 (claim 13). Petitioner argued that while Partovi does not explicitly disclose these values, Tseng remedies this deficiency. Tseng, which also relates to inductive power transfer using PCB coils, teaches that to reduce power loss from the skin effect, "the metal thickness should be more than twice... the skin depth." This teaching directly suggests the limitations of claims 5-7. Tseng also discloses achieving a high Q factor (e.g., 100) by optimizing inductor trace spacing to improve efficiency.
  • Motivation to Combine: A POSITA looking to implement Partovi's inductor would be motivated to improve its efficiency and reduce power loss, which are common goals in the field. Tseng provides explicit, known techniques for achieving these goals by optimizing conductor thickness and Q factor. The combination would have been a predictable application of a known optimization technique to a similar known device.
  • Expectation of Success: A POSITA would have expected success in applying Tseng’s teachings to Partovi’s design, as it involved implementing a well-understood principle (managing skin effect) to achieve the predictable result of minimized conductor loss.

Ground 3: Obviousness over Partovi and Chiang - Claims 1-4, 10, 15-22, 24-27, 29, and 30 are obvious over Partovi in view of Chiang.

• Prior Art Relied Upon: Partovi (Application # 2009/0096413) and Chiang (Patent 7,248,138).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground primarily addressed claim 29, which requires connecting two conductor layers in parallel to form a first "inductor subassembly," and then connecting multiple subassemblies in series. Petitioner argued that while Partovi teaches stacking conductor layers and connecting them in series, it also notes this increases resistance. Chiang explicitly teaches connecting multiple conductor layers "in parallel to decrease the impedance of a particular turn." Chiang shows forming a first turn (a subassembly) by connecting multiple conductor layers in parallel, and then connecting that turn in series with a second, similarly constructed turn.
  • Motivation to Combine: A POSITA, recognizing the increased resistance problem in Partovi's series-connected stacked coils, would be motivated to consult a reference like Chiang, which addresses the same field of PCB-based inductors. Chiang provides a known solution—parallel connections within a turn—to solve the exact problem of high resistance. A POSITA would combine the teachings to create a balanced design that increases inductance (by connecting turns in series, as in Partovi) while minimizing resistance (by connecting layers within each turn in parallel, as in Chiang).
  • Expectation of Success: The combination would predictably result in a functional PCB inductor with improved efficiency. This constituted a combination of familiar elements according to known methods to yield a predictable result.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Partovi with Phan (Patent 7,601,919) to teach conductor layers of about the same thickness. Further grounds relied on three-way combinations of the primary references (Partovi/Chiang/Phan and Partovi/Chiang/Tseng) to address the same claim limitations with redundant teachings.

4. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-8, 10, 12-13, 15-22, and 24-30 of the ’960 patent as unpatentable.