Tianma Microelectronics Co Ltd v. Japan Display Inc

1. Case Identification

• Case #: IPR2021-01061
• Patent #: 10,423,034
• Filed: June 21, 2021
• Petitioner(s): Tianma Microelectronics Co. Ltd.
• Patent Owner(s): Japan Display Inc. and Panasonic Liquid Crystal Display Co., Ltd.
• Challenged Claims: 1-4 and 6-8

2. Patent Overview

• Title: Liquid Crystal Display Device
• Brief Description: The ’034 patent discloses a liquid crystal display (LCD) device with a specific thin-film transistor (TFT) structure, including columnar spacers. The claimed configuration purports to suppress orientation disturbance and transmittance reduction caused by the formation of the spacers.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 and 6-8 are obvious over Ochiai in view of Ando

• Prior Art Relied Upon: Ochiai (Application # 2008/0007679) and Ando (Patent 6,356,330).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Ochiai, a reference for a transflective LCD device, disclosed nearly all limitations of the challenged claims. Specifically, Petitioner contended that Ochiai taught the key structural feature that led to the ’034 patent’s allowance: a semiconductor layer with an “inverted-C shape” where a portion between channel regions overlaps with a second pixel electrode. Petitioner asserted that Ochiai does not explicitly disclose spacers, a limitation of claim 1. Ando was introduced to remedy this, as it taught the well-known use of columnar spacers disposed between substrates to maintain a uniform cell gap, improve display luminance, and enhance contrast. Petitioner argued that adding Ando’s spacer to Ochiai’s device would place it over the TFT, satisfying limitations related to the spacer’s overlap with the semiconductor layer, drain line, organic film, and common electrode.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Ando’s conventional spacer technology with Ochiai’s LCD design to achieve the predictable benefit of a uniform distance between substrates. This would predictably result in improved display uniformity and contrast, as taught by Ando.
  • Expectation of Success: A POSITA would have a high expectation of success, as incorporating spacers was a standard, well-understood practice in LCD manufacturing that required only routine skill and yielded predictable results.

Ground 2: Claim 7 is obvious over Ochiai in view of Ando and Hattori

• Prior Art Relied Upon: Ochiai (Application # 2008/0007679), Ando (Patent 6,356,330), and Hattori (Application # 2008/0018816).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground provided an alternative basis for finding claim 7 obvious, which requires that the "second insulation film contacts the source electrode." Petitioner argued that the primary combination of Ochiai and Ando rendered this limitation obvious. However, to the extent that combination was deemed insufficient, Petitioner asserted that Hattori provided the missing teaching. Hattori disclosed a transparent insulation film that extends through a contact hole to directly contact a source electrode. This structure was taught to create a necessary storage capacitance, thereby improving the pixel’s opening ratio and maintaining a more stable electrical charge.
  • Motivation to Combine: A POSITA would be motivated to modify the Ochiai/Ando device with Hattori’s teaching to gain the known benefits of an improved opening ratio and increased storage capacitance. This would be achieved without needing to increase the electrode area, representing a known technique for improving display performance.
  • Expectation of Success: The modification was presented as a straightforward application of a known design principle to achieve a predictable improvement in display performance, well within the capabilities of a POSITA.

Ground 3: Claim 8 is obvious over Ochiai in view of Ando and Yanagawa

• Prior Art Relied Upon: Ochiai (Application # 2008/0007679), Ando (Patent 6,356,330), and Yanagawa (Patent 6,798,486).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground provided an alternative basis for finding claim 8 obvious, which requires that the spacer is "provided on the second substrate." Petitioner first argued that the term "provided on" simply meant the spacer contacts the second substrate upon assembly, a feature rendered obvious by Ochiai and Ando. If the Board interpreted "provided on" more narrowly to mean "formed on," Petitioner introduced Yanagawa. Yanagawa explicitly taught that forming a spacer on the second (filter) substrate, rather than the first (TFT) substrate, is advantageous because it prevents chemicals used in the spacer etching process from damaging the sensitive thin-film transistors.
  • Motivation to Combine: A POSITA would be motivated to implement the spacer of the Ochiai/Ando device on the second substrate as taught by Yanagawa. This represented a mere design choice between two well-known manufacturing options, with Yanagawa providing a clear rationale for choosing one over the other to prevent TFT degradation and improve manufacturing yield.
  • Expectation of Success: Selecting the manufacturing location for the spacer was a known design choice, and following Yanagawa's explicit teaching to protect TFTs would have been a routine modification with a high expectation of success.

4. Arguments Regarding Discretionary Denial

• Petitioner presented substantial arguments against discretionary denial of the inter partes review (IPR) under both 35 U.S.C. §314(a) (Fintiv factors) and §325(d).
• Arguments against Fintiv Denial: Petitioner argued that the merits of the petition were exceptionally strong and that it had stipulated not to pursue the same invalidity grounds in the parallel district court litigation, which strongly favored institution by mitigating concerns of duplicative efforts. Petitioner also contended that the district court trial date was speculative due to a pending motion to transfer venue, and that it filed the IPR petition with diligence after infringement contentions were served.
• Arguments against §325(d) Denial: Petitioner argued that the prior art references relied upon in the petition (Ochiai, Ando, Hattori, Yanagawa) were not cited or considered during the original prosecution. Furthermore, the petition's arguments and prior art combinations were not cumulative to those before the Examiner, as they specifically addressed the very feature—the overlap of the semiconductor layer with the second pixel electrode—that the Examiner identified as the basis for allowing the claims.

5. Relief Requested

• Petitioner requested the institution of an IPR and cancellation of claims 1-4 and 6-8 of Patent 10,423,034 as unpatentable under 35 U.S.C. §103.