PTAB

IPR2025-01004

Hisense USA Corp v. Phenix Longhorn LLC

Key Events

Petition

petition

Title: Gamma Reference Voltage Generator
Brief Description: The ’788 patent describes a method for calibrating liquid crystal displays (LCDs) to a desired gamma curve to compensate for manufacturing variations. The method involves testing the display with a separate optical sensor, varying gamma voltage levels with a separate control circuit, optimizing those levels with an algorithm, and storing the results in a reprogrammable, non-volatile memory.

Prior Art Relied Upon: Nonomura (JP H06217239) and Kang (Application # 2002/0063666).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Nonomura disclosed a method for calibrating an LCD projector to compensate for panel-to-panel variations. Nonomura’s system included an external luminance meter (sensor), an adjustment control apparatus (control circuit), and non-volatile memory for storing correction data, allegedly meeting most limitations of the independent claims. Petitioner contended that to the extent Nonomura did not explicitly teach applying gamma voltages "on columns of" a display, Kang supplied this teaching by describing a conventional LCD architecture with column drivers that receive and apply gamma voltages.
- Motivation to Combine: Petitioner asserted that both references are in the same field of gamma correction. A person of ordinary skill in the art (POSITA) would combine Nonomura's calibration system with Kang’s well-known column driver architecture to apply the calibrated voltages in a standard LCD panel, thereby achieving improved and predictable display quality.
- Expectation of Success: A POSITA would have had a reasonable expectation of success, as the combination involved applying a known calibration technique to a standard display structure.

Prior Art Relied Upon: Uehara (JP H07152347) and Kang (Application # 2002/0063666).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Uehara provided an alternative primary reference disclosing the core inventive concept. Uehara taught a gamma correction method for an LCD that used a luminance meter, a personal computer as the control circuit, and reprogrammable, non-volatile EEPROMs to store correction data. This system measured light transmittance and calculated correction data to compensate for manufacturing variability. As with the Nonomura combination, Petitioner relied on Kang to explicitly disclose the application of gamma voltages to the columns of the LCD panel via column drivers.
- Motivation to Combine: The motivation was similar to Ground 1. A POSITA would be motivated to integrate the standard column driver architecture of Kang into Uehara’s gamma correction system to implement the calibration on a conventional LCD, a predictable modification to achieve improved display performance.
- Expectation of Success: Petitioner contended that success would be expected due to the routine nature of combining a known calibration method with a standard pixel access architecture.

Prior Art Relied Upon: Tobiya (Application # 2002/0036646) and Kang (Application # 2002/0063666).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued Tobiya described a display characteristic correction system that calibrates an LCD to a desired gamma curve. Tobiya’s system used a luminance meter and an external computer to generate correction data, which was stored in a look-up table (LUT) implemented in rewritable, non-volatile memory (e.g., EEPROM). The system optimized gamma levels by comparing measured display characteristics to a target curve. Petitioner again asserted that Kang taught the missing element of applying these gamma reference voltages specifically to the columns of the display.
- Motivation to Combine: Petitioner asserted a POSITA would combine Tobiya's LUT-based calibration method with Kang's column-based architecture. This would be a straightforward implementation of Tobiya's correction system onto a conventional display, which was a well-known design choice for achieving predictable results.
- Expectation of Success: The combination was presented as a predictable integration of known elements, giving a POSITA a reasonable expectation of success.

Petitioner argued that certain claim terms should be construed as means-plus-function limitations under 35 U.S.C. § 112, ¶6, as they allegedly fail to recite sufficient structure for performing their claimed function.
Key terms identified for this construction included:
- "gamma reference control capability": Function of programming and storing gamma reference values.
- "control circuit": Function of varying gamma reference voltage levels on display columns.
- "means for executing a predetermined algorithm": Function of executing an algorithm to optimize gamma voltage levels based on sensor data.

§314(a) (Fintiv Factors): Petitioner argued against discretionary denial under Fintiv, stating that although a co-pending litigation exists, the Petitioner (Hisense USA Corporation) was only recently served (October 16, 2024), making the petition timely. Petitioner also contended that the district court trial is likely to be delayed past the IPR statutory deadline and that the petition presents compelling merits.
§325(d): Petitioner argued denial under §325(d) is inappropriate because the petition does not present the same or substantially the same prior art or arguments previously presented to the USPTO. None of the asserted prior art references (Nonomura, Uehara, Tobiya, Kang) were considered during the original prosecution.

Petitioner requests institution of an inter partes review and cancellation of claims 1-3 and 5-6 of the ’788 patent as unpatentable.