DCT
8:20-cv-00125
Polaris PowerLED Tech LLC v. LG Electronics Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Polaris PowerLED Technologies, LLC (Delaware)
- Defendant: LG Electronics, Inc. (Republic of Korea) and LG Electronics U.S.A., Inc. (Delaware)
- Plaintiff’s Counsel: Feinberg Day Kramer Alberti Lim Tonkovich & Belloli LLP
- Case Identification: 8:20-cv-00125, C.D. Cal., 01/21/2020
- Venue Allegations: Plaintiff alleges venue is proper based on Defendant's physical presence, business registrations, and substantial business activities within the district, including the sale and promotion of the accused products.
- Core Dispute: Plaintiff alleges that Defendant’s televisions and mobile devices infringe patents related to LED backlight driving circuits for local dimming and systems for automatically controlling display brightness based on ambient light.
- Technical Context: The technologies at issue address power efficiency and display quality in modern electronics by enabling zone-specific backlight control and by dynamically adjusting screen brightness in response to both environmental light and user preferences.
- Key Procedural History: The complaint alleges Defendant had notice of the patents-in-suit prior to the lawsuit, based on a notice letter sent on August 29, 2019. It also alleges earlier knowledge, dating back to 2008 and 2013, based on patent publications from LG-affiliated entities that cite the patents-in-suit as prior art.
Case Timeline
| Date | Event |
|---|---|
| 2003-12-16 | ’087 Patent Priority Date |
| 2004-02-09 | ’117 Patent Priority Date |
| 2004-12-14 | ’087 Patent Application Filing Date |
| 2007-07-03 | ’087 Patent Issue Date |
| 2008-01-17 | LG Innotek publication allegedly provides notice of ’087 Patent |
| 2008-12-17 | ’117 Patent Application Filing Date |
| 2012-07-17 | ’117 Patent Issue Date |
| 2013-08-13 | LG Display publication allegedly provides notice of ’117 Patent |
| 2019-08-29 | Plaintiff sends notice letter to LG regarding both patents |
| 2020-01-21 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,239,087 - "Method and Apparatus to Drive LED Arrays Using Time Sharing Technique," issued July 3, 2007
The Invention Explained
- Problem Addressed: The patent describes the need for backlight systems to illuminate displays, such as in LCD televisions, and proposes a current-mode driver to generate a regulated current for the light sources, which helps ensure stable light output and long operating life (’087 Patent, col. 1:47-59).
- The Patented Solution: The invention discloses a "multi-load time sharing driver" that uses a single current source to power a plurality of light sources, such as different zones in an LED backlight. This is achieved through a "network of semiconductor switches coupled in series." Each light source is associated with a switch. The system selectively directs the regulated current to a specific light source by opening its associated switch, which diverts the current from a bypass path through that light source (’087 Patent, Abstract; col. 18:5-14).
- Technical Importance: This time-sharing technique provides a method for a single driver circuit to independently control multiple segments of a backlight, a key principle behind "local dimming" technology used to improve contrast and power efficiency in LED displays (’087 Patent, col. 18:2-9).
Key Claims at a Glance
- The complaint asserts independent Claim 1 (’087 Patent, col. 18:10-14; Compl. ¶25).
- Claim 1 requires:
- a current source configured to provide a regulated current;
- a network of semiconductor switches coupled in series; and
- a plurality of light sources in a backlight system, each associated with a semiconductor switch, where the switch "selectively opens to allow the associated light source to conduct the regulated current."
- The complaint reserves the right to assert additional claims (Compl. ¶26).
U.S. Patent No. 8,223,117 - "Method and Apparatus to Control Display Brightness with Ambient Light Correction," issued July 17, 2012
The Invention Explained
- Problem Addressed: The patent notes that while reducing backlight brightness in low-light conditions saves power in battery-operated devices, prior systems for doing so were "crude" and did not adequately account for user preferences or eye fatigue (’117 Patent, col. 1:46-54).
- The Patented Solution: The invention proposes a brightness control circuit that mathematically combines two inputs: a signal from an ambient light sensor and a user-selected brightness preference. A "multiplier" generates a combined signal from these inputs, and a "dark level bias" adjusts this signal to ensure that the screen brightness is maintained above a minimum level even when ambient light approaches zero, preventing the display from becoming completely dark unintentionally (’117 Patent, Abstract; col. 2:55-61).
- Technical Importance: The technology allows for an automatic brightness control system that intelligently adapts to both environmental lighting and individual user settings, enhancing both ergonomics and power management (’117 Patent, col. 2:1-5).
Key Claims at a Glance
- The complaint asserts independent Claim 1 (’117 Patent, col. 11:30-49; Compl. ¶50).
- Claim 1 requires:
- a first input to receive a user signal for a brightness setting;
- a light sensor to sense ambient light and output a sensing signal;
- a multiplier to generate a combined signal from the user and sensing signals; and
- a dark level bias to adjust the combined signal, ensuring brightness remains above a predetermined level when ambient light is near zero.
- The complaint reserves the right to assert additional claims (Compl. ¶51).
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are LG televisions with "Local Dimming" and "TruMotion" features (e.g., model 55UJ7700) and LG smartphones (e.g., V Series and G Series) with automatic brightness control (Compl. ¶26, ¶51, ¶60).
Functionality and Market Context
- The complaint alleges the accused LG televisions contain an LED control board, power supply, and mainboard that work together to individually control different strings or "zones" of LEDs in the backlight, a feature marketed as "Local Dimming" (Compl. ¶27, ¶29). These TVs also allegedly include an "Energy Saving" mode that uses an ambient light sensor to automatically adjust screen brightness (Compl. ¶52).
- The accused LG smartphones are alleged to contain an ambient light sensor and an "Auto" brightness feature that adjusts the screen's brightness based on ambient light conditions and a user-set baseline brightness level (Compl. ¶61, ¶63).
IV. Analysis of Infringement Allegations
'087 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a current source configured to provide a regulated current | The accused TVs allegedly include a power supply IC and associated circuitry that form a resonant switch mode power supply, which provides a regulated current to the LED driver chip (Compl. ¶30-31). | ¶30 | col. 5:21-26 |
| a network of semiconductor switches coupled in series | The LED control board in the accused TV allegedly includes an LED driver chip (LGP06B) and multiple N-Channel FETs (4NF20L). The complaint alleges these FETs are semiconductor switches coupled in series with each other and the current source (Compl. ¶34, ¶37). | ¶34, ¶37 | col. 17:15-19 |
| a plurality of light sources in a backlight system, each light source associated with a semiconductor switch, wherein the semiconductor switch selectively opens to allow the associated light source to conduct the regulated current | The accused TV backlight allegedly contains six sections of LEDs (light sources), each associated with an N-Channel FET (semiconductor switch). The LED drivers are configured to selectively control these switches to implement local dimming by directing current through the desired LED section (Compl. ¶39). | ¶39 | col. 18:5-14 |
- Identified Points of Contention:
- Scope Questions: The patent’s Figure 8 depicts a simple, direct series connection of switches. The complaint alleges infringement via a more complex architecture involving a power supply board, an LED control board, a driver IC, and FETs (Compl. ¶36-37). A central question may be whether this multi-component, functionally-series architecture falls within the scope of a "network of semiconductor switches coupled in series" as construed from the patent.
- Technical Questions: Claim 1 requires a switch to "selectively open" to allow current conduction through the light source. The specification clarifies this refers to opening a bypass path around the light source (’087 Patent, col. 17:25-29). The infringement analysis will depend on whether the accused N-Channel FETs operate in this specific manner or use a more conventional switching method to control the LED strings.
'117 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a first input configured to receive a user signal indicative of a user selectable brightness setting | The accused TVs and smartphones provide user interfaces, such as the "Energy Saving" menu or a brightness slider bar, for users to set a desired brightness level (Compl. ¶52, ¶61-62). The complaint includes a screenshot of the LG V40 ThinQ's brightness adjustment screen (Compl. ¶62, p. 20). | ¶52, ¶61-62 | col. 3:20-24 |
| a light sensor configured to sense ambient light and to output a sensing signal indicative of the ambient light level | The accused TVs and smartphones are alleged to include a front-facing ambient light sensor that outputs a signal corresponding to the ambient light level (Compl. ¶53, ¶63). | ¶53, ¶63 | col. 2:36-40 |
| a multiplier configured to selectively generate a combined signal based on both the user signal and the sensing signal | This function is allegedly implemented in software that processes variables from the user and sensing signals. The complaint provides a graph from testing an LG TV, which it claims "plainly indicates the presence of a multiplier" (Compl. ¶56, p. 17). For smartphones, it alleges the process "includes multiplication" (Compl. ¶68). | ¶54-56, ¶67-68 | col. 3:31-34 |
| a dark level bias configured to adjust the combined signal to generate a brightness control signal...such that the brightness control signal is maintained above a predetermined level when the ambient light level decreases to approximately zero | This function is allegedly implemented as a "software variable" or function that prevents the brightness from dropping below a minimum level. The complaint includes graphs for both the TV and smartphone showing that at 0 lux, the display luminance remains at a non-zero minimum, which it attributes to the dark level bias (Compl. ¶59, p. 18; Compl. ¶68, p. 22). | ¶57-59, ¶69-72 | col. 2:55-61 |
- Identified Points of Contention:
- Scope Questions: Claim 1 recites structural terms like "circuit," "multiplier," and "bias." The complaint alleges these limitations are met by software, including "software variables" and mathematical functions (Compl. ¶54, ¶58). A dispositive issue will be whether these software implementations can be found to be structurally equivalent to the claimed hardware elements, a question central to claim construction.
- Technical Questions: The complaint relies on graphs from external testing to evidence the "multiplier" and "dark level bias" functions (Compl. ¶56, ¶59). A key evidentiary question will be whether this testing accurately reflects the internal operation of the accused software and whether the algorithms used by LG perform the specific functions of "multiplication" and "adjust[ment]" in the manner required by the claims.
V. Key Claim Terms for Construction
For the ’087 Patent
- The Term: "network of semiconductor switches coupled in series"
- Context and Importance: The plaintiff’s infringement theory for the ’087 Patent depends on establishing that the accused TV’s distributed architecture—comprising a power supply, driver IC, and FETs across multiple boards—constitutes a "network...coupled in series." Practitioners may focus on this term because the defendant will likely argue that its product architecture does not meet this limitation as it is depicted in the patent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself is general and does not mandate a specific physical layout. The specification describes using a "string of semiconductor switches...coupled in series" which may be interpreted as a functional rather than a strictly physical arrangement (’087 Patent, col. 17:15-17).
- Evidence for a Narrower Interpretation: The only embodiment shown (Figure 8) depicts a simple, direct physical series connection of switches (820, 822, 824, 826). An argument may be made that the claims should be limited to this disclosed arrangement, where the switches are directly connected to one another.
For the ’117 Patent
- The Term: "multiplier"
- Context and Importance: The complaint alleges this structural element is met by a software process that "includes multiplication" (Compl. ¶55). The construction of "multiplier" will be critical in determining whether a software algorithm that achieves a multiplicative result infringes a claim reciting a structural component.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the multiplier's function broadly, stating it "generates a brightness control signal based on a mathematical product" of the two inputs, which supports a functional interpretation (’117 Patent, col. 2:41-44).
- Evidence for a Narrower Interpretation: The patent’s block diagrams (e.g., Fig. 1) depict the "multiplier" (106) as a distinct structural block. A party could argue this implies a dedicated hardware or software module, not merely a step within a larger, more complex algorithm.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that LG induces infringement by providing customers with instructions, user manuals, and training videos that direct them to use the accused features, such as "Local Dimming" on TVs and "Auto" brightness on smartphones (Compl. ¶40, ¶73).
- Willful Infringement: The complaint alleges willful infringement based on both pre-suit and alleged constructive knowledge. It cites a direct notice letter sent to LG on August 29, 2019 (Compl. ¶41, ¶74). It further alleges that LG-affiliated entities cited the patents-in-suit as prior art in their own patent publications as early as 2008 and 2013, suggesting an earlier date of awareness (Compl. ¶43, ¶76).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue for the ’117 Patent will be one of structural equivalence: can the terms "multiplier" and "dark level bias," which are recited as circuit components, be met by the accused products' software algorithms and "software variables" as alleged in the complaint? The outcome will likely depend on claim construction and the extent to which software can be deemed a structure.
- For the ’087 Patent, a key dispute will be one of architectural scope: does the claim term "network of semiconductor switches coupled in series," illustrated as a simple, direct connection in the patent, read on the more complex, multi-board power and control architecture allegedly used in the accused televisions?
- A significant legal battle may arise over willfulness: can the plaintiff establish that LG had pre-suit knowledge of the patents based on citations in publications from affiliated corporate entities, years before receiving a direct notice letter? This could substantially impact the timeline for potential damages.