DCT
2:23-cv-00478
Phenix Longhorn LLC v. Innolux Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Phenix Longhorn LLC (Texas)
- Defendant: Innolux Corporation (Taiwan)
- Plaintiff’s Counsel: Womble Bond Dickinson (US) LLP; Findlay Craft, P.C.
- Case Identification: 2:23-cv-00478, E.D. Tex., 10/04/2024
- Venue Allegations: Venue is alleged to be proper as Defendant Innolux is a foreign entity, which may be sued in any judicial district under 28 U.S.C. § 1391(c). The complaint also alleges that Defendant has committed acts of infringement and has minimum contacts with the district.
- Core Dispute: Plaintiff alleges that Defendant’s liquid crystal display (LCD) panel modules, which are incorporated into televisions sold in the U.S., infringe patents related to programmable gamma reference voltage generators for display calibration.
- Technical Context: The technology concerns integrated circuits that automate gamma correction for LCDs, a process critical for achieving consistent, high-quality images by compensating for manufacturing variations and non-linear pixel responses.
- Key Procedural History: The complaint notes that U.S. Patent No. 7,233,305 survived an Inter Partes Review challenge in 2019, with the Patent Trial and Appeal Board denying institution. It also alleges that Defendant had pre-suit knowledge of the asserted patents through business discussions with Plaintiff's predecessor-in-interest, Alta Analog, Inc., between 2007 and 2010.
Case Timeline
| Date | Event |
|---|---|
| 2003-06-11 | Priority Date for ’305 and ’788 Patents |
| 2007-06-19 | Issue Date for U.S. Patent No. 7,233,305 |
| 2009-07-07 | Issue Date for U.S. Patent No. 7,557,788 |
| 2019-01-24 | PTAB denies institution of IPR for the ’305 Patent |
| 2024-10-04 | First Amended Complaint filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,233,305 - "Gamma Reference Voltage Generator" (Issued June 19, 2007)
The Invention Explained
- Problem Addressed: The patent addresses the problem that manufacturing variations cause LCD panels to display images differently, requiring panel-specific calibration. The conventional solution involved manually selecting and soldering "Select-On-Test Resistors," a costly, labor-intensive process that prevented automated assembly and made it difficult to adjust gamma characteristics post-manufacturing (’305 Patent, col. 1:17-45).
- The Patented Solution: The invention is an integrated circuit that replaces the manual resistor-based system. It uses non-volatile memory cells to store and output precise gamma reference voltages, which control the display's brightness levels (’305 Patent, Abstract). This circuit can be programmed during manufacturing and retains the calibration data without power. A key feature is the organization of memory cells into multiple "banks," allowing the device to store and switch between different gamma profiles for various applications or viewing conditions (’305 Patent, col. 6:50-58; Fig. 6). The complaint includes a six-panel image demonstrating how different gamma correction values alter the curvature, color, and contrast of a human face on a display (Compl. ¶23).
- Technical Importance: This integrated and reprogrammable solution was designed to significantly reduce manufacturing costs and time by enabling automated calibration, while also providing the flexibility to support multiple gamma curves on a single chip (Compl. ¶24).
Key Claims at a Glance
- The complaint asserts at least Claims 1, 2, and 5 of the ’305 Patent (Compl. ¶75). Independent Claim 1 recites:
- An integrated circuit for producing voltage signals on a plurality of outputs comprising:
- a plurality of non-volatile storage cells;
- circuits for programming coupled to a multiplexer for addressing and programming said storage cells;
- drivers connected to the storage cells and outputs;
- a plurality of inputs connected to the multiplexer for addressing the storage cells;
- wherein the non-volatile storage cells are organized into two or more banks, with each bank containing a predetermined gamma reference voltage signal display condition; and
- a "means to switch between the banks" based on external signals.
U.S. Patent No. 7,557,788 - "Gamma Reference Voltage Generator" (Issued July 7, 2009)
The Invention Explained
- Problem Addressed: As with the ’305 Patent, the invention targets the inefficiencies of manual gamma correction in LCD manufacturing (’788 Patent, col. 1:29-45).
- The Patented Solution: As a continuation of the ’305 Patent, the ’788 Patent claims a method for calibrating an LCD. The method comprises providing a display with a reprogrammable, non-volatile gamma control capability, testing the display’s optical output with a separate sensor, varying the gamma voltages via a control circuit, using a separate "means for executing a predetermined algorithm" to optimize the voltage levels based on the sensor data, and then storing the optimized levels in the non-volatile control unit (’788 Patent, Abstract; col. 7:23-42).
- Technical Importance: This method provides a framework for fully automating the panel calibration process on a production line, using a closed-loop feedback system (with an optical sensor) to achieve precise, panel-specific gamma curves (Compl. ¶24).
Key Claims at a Glance
- The complaint asserts at least Claim 1 of the ’788 Patent (Compl. ¶83). Independent Claim 1 recites:
- A method of calibrating a liquid crystal display to a desired gamma curve, comprising the steps of:
- providing the display with an electrically reprogrammable and non-volatile gamma reference control capability;
- testing the display with at least one sensor with optical input, where the sensor is separate from the display;
- varying gamma reference voltage levels on the display's columns using a control circuit that is separate from the display;
- optimizing the gamma reference voltage levels using a "means for executing a predetermined algorithm" that is separate from the display and uses data from the sensor; and
- storing the optimized gamma reference voltage levels in the gamma reference control capability.
III. The Accused Instrumentality
- Product Identification: The complaint identifies "Innolux LCD panel modules that include a TCON board with a programmable gamma integrated circuit, i.e., Pgamma chip, with at least two banks" (Compl. ¶40). Specific accused chip models include CM602, CM603, IN602, and IN603 (Compl. ¶40). These modules are components within finished "Infringing TV Products" sold under brands such as Samsung, LG, Vizio, Sharp, RCA, and Panasonic (Compl. ¶¶41-42).
- Functionality and Market Context: The accused LCD panel modules are alleged to contain the screen and the electronic circuits that control it, including a timing and control (TCON) board (Compl. ¶28). This TCON board is alleged to house the "Pgamma chip" that performs the gamma correction necessary to produce a high-quality image (Compl. ¶¶28, 40). The complaint alleges that Defendant Innolux manufactures these modules and sells them to Original Equipment Manufacturers (OEMs), such as Samsung Mexicana S.A. de C.V. ("SAMEX"), which then incorporate them into televisions intended for and sold in the U.S. market (Compl. ¶¶5, 33, 42). The complaint alleges the U.S. is a major and high-volume market for these products (Compl. ¶33).
IV. Analysis of Infringement Allegations
’305 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An integrated circuit for producing voltage signals on a plurality of outputs comprising: a plurality of non-volatile storage cells; | The accused Pgamma chip is an integrated circuit containing non-volatile storage cells. | ¶57 | col. 2:21-23 |
| circuits for programming coupled to a multiplexer for addressing and programming said storage cells... | The Pgamma chip contains circuits coupled to a multiplexer for addressing and programming the storage cells based on inputs. | ¶57 | col. 3:48-55 |
| drivers connected to said storage cells and to the plurality of outputs; | The Pgamma chip contains drivers connected to the storage cells and outputs. | ¶57 | col. 3:12-18 |
| said non-volatile storage cells are organized into two or more banks of cells wherein each bank contains a predetermined gamma reference voltage signal display condition; | The non-volatile storage cells in the Pgamma chip are organized into at least two banks, each with a predetermined gamma condition. | ¶57 | col. 6:50-52 |
| and means to switch between the banks based on one or more external signals is provided on said integrated circuit. | The Pgamma chip has the ability to be switched between banks by external signals. | ¶57 | col. 6:52-58 |
- Identified Points of Contention:
- Technical Questions: The complaint's infringement allegations for the '305 Patent in paragraph 57 largely mirror the language of Claim 1. A central question for the court will be an evidentiary one: what technical evidence demonstrates that the accused Pgamma chips (e.g., CM602, IN603) actually possess the specific architecture claimed, such as "non-volatile storage cells" and circuitry that organizes them into switchable "banks"?
- Scope Questions: The final element is a means-plus-function limitation. Its scope is defined by the structure disclosed in the patent for performing the switching function. A dispute may arise over whether the structure in the accused chips is the same as or equivalent to the "Bank Select" logic responsive to address inputs (B0, B1, B2) described in the patent (’305 Patent, Fig. 6).
’788 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| providing said display with gamma reference control capability which is electrically reprogrammable and non-volatile; | The accused process involves providing a display with the Infringing Panel Module, which has reprogrammable and non-volatile gamma control. | ¶68 | col. 2:32-34 |
| testing said display with at least one sensor with optical input, wherein said sensor is separate from said display; | The manufacturing and calibration process for the displays involves testing them with a separate optical sensor. | ¶68 | col. 7:26-29 |
| varying gamma reference voltage levels on columns of said display by a control circuit, where said control circuit is separate from said display; | The process involves varying gamma voltage levels using a control circuit separate from the display itself. | ¶68 | col. 1:26-30 |
| optimizing said gamma reference voltage levels using means for executing a predetermined algorithm... separate from said display...; and | The process uses separate means, such as a computer with algorithms, to optimize the gamma levels based on sensor data. | ¶68 | col. 7:15-19 |
| storing said gamma reference voltage levels in said gamma reference control capability. | The optimized gamma levels are stored in the non-volatile capability of the Pgamma chip. | ¶68 | col. 7:40-42 |
- Identified Points of Contention:
- Legal Questions: The complaint alleges that the accused "LCD panel modules and/or finished television sets are made using a method" of calibration (Compl. ¶68). As this is a method claim, a primary issue may be proving that a single entity performs all the required steps. The complaint alleges Innolux "tests and calibrates and/or directs and controls others to test and calibrate" (Compl. ¶45), raising the question of whether infringement is direct by Innolux or must be proven under a theory of divided infringement.
- Scope Questions: The "optimizing" step is a means-plus-function limitation. The patent suggests this could be performed by a PC connected to the system (’788 Patent, col. 7:15-19). The infringement analysis may focus on identifying the structure used in the accused manufacturing process and determining if it is equivalent to the structure disclosed in the patent.
V. Key Claim Terms for Construction
’305 Patent, Claim 1
The Term: "non-volatile storage cells"
Context and Importance: This term is fundamental to the invention's distinction from prior art that was either volatile or required permanent, unchangeable resistors. The definition will be critical for determining if the memory used in the accused Pgamma chips falls within the scope of the claims.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification generally refers to "non-volatile, programmable memory" where "the gamma correction is retained" if power is removed, suggesting any memory technology meeting this functional requirement could be covered (’305 Patent, col. 2:21-24).
- Evidence for a Narrower Interpretation: The specification also describes a more specific embodiment using "programmable analog floating gate memory cells" (’305 Patent, col. 3:51). A party could argue that the claims should be construed as limited to this specific type of analog non-volatile memory.
The Term: "means to switch between the banks"
Context and Importance: As a means-plus-function limitation under 35 U.S.C. § 112, paragraph 6, its scope is not the literal words but the corresponding structure disclosed in the specification and its equivalents. Practitioners may focus on this term because infringement requires identifying an equivalent structure in the accused device.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation (Equivalents): The function is "to switch between the banks." Any structure that accomplishes this function using technology developed after the patent could be argued as an equivalent.
- Evidence for a Narrower Interpretation (Disclosed Structure): The specification discloses that the "banks of gamma voltages are stored and selected through the three address inputs B0, B1, B2" (’305 Patent, col. 6:52-54). The corresponding structure is the "Bank Select" logic block shown in Figure 6 that receives these address inputs to select a group of memory cells. The scope may be limited to this specific logic implementation and its structural equivalents.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement against Innolux for both patents (Compl. ¶¶53, 64). The factual basis includes allegations that Innolux, with knowledge of the patents from prior business dealings, supplies the infringing panel modules to downstream manufacturers (e.g., SAMEX) with the intent that they be incorporated into televisions imported and sold in the U.S., thereby directly infringing the claims (Compl. ¶¶33, 53, 62).
- Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge. It claims that Innolux knew of the ’305 Patent since at least 2007 and the ’788 Patent since at least 2009, citing "past dealings with Alta" (Plaintiff's predecessor-in-interest) regarding the patented technology (Compl. ¶¶60-61, 71-72).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of technical proof: can Plaintiff produce evidence that the accused "Pgamma chips" manufactured by Innolux contain the specific architecture recited in Claim 1 of the ’305 patent, particularly the "non-volatile storage cells" organized into multiple, switchable "banks"? The resolution may depend on reverse engineering and analysis of the accused chips.
- The case raises a critical question of attribution for method infringement: for the ’788 patent, can Plaintiff establish that a single actor, such as Innolux or its customer SAMEX, performs every step of the claimed calibration method? If the steps are divided, the outcome may hinge on whether Plaintiff can prove Innolux "directs or controls" its customers' actions sufficiently to satisfy the legal standard for divided infringement.
- A further question will be one of claim scope: how will the court construe the means-plus-function limitations, such as the "means to switch" in the ’305 patent and the "means for executing a predetermined algorithm" in the ’788 patent? The analysis will likely focus on the specific structures disclosed in the patents (e.g., bank select logic, a PC running software) and whether the corresponding structures in the accused products and processes are equivalent.