Luminatronics LLC v. Analog Devices Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Luminatronics LLC (DE)
  • Defendant: Analog Devices, Inc. (MA)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 2:25-cv-00135, E.D. Tex., 02/05/2025
• Venue Allegations: Venue is alleged to be proper based on Defendant maintaining an established place of business within the district and having committed alleged acts of patent infringement there.
• Core Dispute: Plaintiff alleges that certain of Defendant's products, which are not specified by name in the complaint, infringe a patent related to electronic circuits for driving Light Emitting Diodes (LEDs).
• Technical Context: The technology concerns methods for improving the power efficiency and performance of LED lighting systems when powered by a standard alternating current (AC) source.
• Key Procedural History: The patent-in-suit is an assignment to the Plaintiff. The patent document indicates it is a continuation of a prior application that claims priority to a 2013 provisional application. The complaint does not mention any prior litigation or administrative proceedings involving the patent.

Case Timeline

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,807,836 - “Light emitting diode light structures”

• Patent Identification: U.S. Patent No. 9,807,836, “Light emitting diode light structures,” issued October 31, 2017.

The Invention Explained

• Problem Addressed: The patent’s background section identifies a key technical challenge for LED lights powered by an AC mains supply: achieving a high power factor (PF). Because LEDs only conduct current above a certain voltage, they tend to draw power in short bursts near the peak of the AC voltage waveform, which is an inefficient use of power from the grid and results in a low PF (’836 Patent, col. 2:45-65). This non-linear power draw can also cause undesirable flicker in the light output (’836 Patent, col. 3:1-13).
• The Patented Solution: The invention proposes a circuit that dynamically adjusts the active portion of a series-connected string of LEDs. The circuit uses control circuitry to monitor the rectified AC voltage. When the voltage is below a set threshold (i.e., during the parts of the AC cycle away from the peak), a switch is activated to bypass, or "shunt," a portion of the LED string (’836 Patent, col. 7:10-22). This allows the remaining, smaller group of LEDs to illuminate at lower voltages, causing the overall device to draw current for a longer portion of the AC cycle. This technique is intended to make the LED bulb behave more like a simple resistive load, thereby improving the power factor and the peak-to-average power ratio (’836 Patent, col. 8:1-7). Figure 6 illustrates this core concept, showing control circuitry (616) and a switch (617) that shunts a second group of LEDs (630).
• Technical Importance: This circuit architecture represents an approach to solving the power factor correction problem in AC-driven LEDs without requiring more complex and expensive power conversion electronics, a significant consideration for cost-sensitive consumer lighting products (’836 Patent, col. 2:55-65).

Key Claims at a Glance

• The complaint alleges infringement of "one or more claims" without specifying them, instead referencing an unprovided exhibit (Compl. ¶11). The first independent apparatus claim is Claim 1.
• Independent Claim 1 of the ’836 Patent recites:
  • A bridge rectifier configured to be powered by an alternating current power source and to produce a rectified output;
  • Control circuitry coupled to the bridge rectifier, configured to produce a shunt signal when the rectified output is less than a threshold voltage;
  • A series connected LED string coupled directly to the bridge rectifier, having a first and a second group of LEDs; and
  • A switch coupled to a first side of the second group of LEDs and controlled by the shunt signal to deactivate the second group of LEDs.
• The complaint’s general allegation of infringing "one or more claims" preserves the right to assert other independent claims (e.g., 8 and 15) and any dependent claims.

III. The Accused Instrumentality

Product Identification

• The complaint does not identify any specific accused products by name. It refers to them generically as the "Exemplary Defendant Products" and states they are identified in charts within an unprovided Exhibit 2 (Compl. ¶11, ¶16).

Functionality and Market Context

• The complaint does not provide sufficient detail for analysis of the accused products' functionality. It makes conclusory allegations that the products "practice the technology claimed by the '836 Patent" (Compl. ¶16). No allegations are made regarding the products' specific market context or commercial importance.

IV. Analysis of Infringement Allegations

The complaint alleges that infringement is detailed in claim charts provided as Exhibit 2, which was not available for this analysis (Compl. ¶16-17). The narrative infringement theory is that the "Exemplary Defendant Products" contain components that satisfy, either literally or under the doctrine of equivalents, all elements of the asserted claims of the ’836 Patent (Compl. ¶11). The complaint further alleges direct infringement occurs through Defendant’s internal testing and use of the products (Compl. ¶12).

No probative visual evidence provided in complaint.

Identified Points of Contention

Based on the claim language and the general infringement theory, the dispute may involve several technical and legal questions:

• Scope Questions: Claim 1 requires the LED string to be "coupled directly to the bridge rectifier." The interpretation of "directly" will be a key issue if the accused products contain any intervening components, such as filters or current-limiting resistors, between the rectifier and the LED string.
• Technical Questions: A central question will be what structure within the accused products constitutes the "control circuitry" and how it operates. The analysis will focus on whether the accused circuitry in fact generates a "shunt signal when the rectified output is less than a threshold voltage" as claimed, or if it performs a different function or operates based on different principles. Similarly, evidence will be required to show that a component functions as the claimed "switch" to "deactivate" a group of LEDs in the manner described by the patent.

V. Key Claim Terms for Construction

"control circuitry"

• Context and Importance: This term defines the core logic of the invention. Its construction will determine whether only specific circuit implementations fall within the claim scope or if a broader range of functionally equivalent circuits could infringe.
• Intrinsic Evidence for a Broader Interpretation: The claim defines the term functionally: "configured to produce a shunt signal when the rectified output is less than a threshold voltage" (’836 Patent, col. 22:14-16). A plaintiff may argue this language was intended to cover any circuit that performs this specified function, regardless of its specific implementation.
• Intrinsic Evidence for a Narrower Interpretation: The specification discloses specific embodiments, such as a "ratio metric series resistor string" coupled with an "inverter" (’836 Patent, col. 7:40-44). A defendant may argue that the term should be construed as limited to these disclosed structures or their equivalents, particularly the transistor-and-resistor arrangement shown in Figure 7A.

"deactivate the second group of LEDs"

• Context and Importance: The meaning of "deactivate" is central to the infringement analysis, as it describes the action performed by the switch on the LEDs.
• Intrinsic Evidence for a Broader Interpretation: A party could argue "deactivate" simply means to turn the LEDs off or render them non-illuminating, potentially covering mechanisms other than shunting.
• Intrinsic Evidence for a Narrower Interpretation: The specification consistently describes the "switch" as creating a bypass. For example, the switch is "connected in shunt across the second group of LEDs" (’836 Patent, col. 7:50-52). The abstract also states the switch is controlled by the shunt signal to "deactivate the second group of LEDs" (’836 Patent, Abstract). This suggests that the claimed "deactivation" is achieved specifically by shunting current around the LEDs, not by other means like opening the circuit.

VI. Other Allegations

Indirect Infringement

• The complaint alleges induced infringement, stating that Defendant distributes "product literature and website materials" that instruct end users to operate the accused products in an infringing manner (Compl. ¶14).

Willful Infringement

• The allegation of willfulness is based on alleged post-suit knowledge. The complaint asserts that the filing and service of the complaint itself provides Defendant with "actual knowledge of infringement" and that any continued infringing activity thereafter is willful (Compl. ¶13-14). No facts are alleged to support pre-suit knowledge of the patent or the alleged infringement.

VII. Analyst’s Conclusion: Key Questions for the Case

• An Evidentiary Question of Technical Operation: As the complaint lacks specific details about the accused products, a threshold issue will be evidentiary: does discovery reveal that Defendant’s products contain a circuit architecture that dynamically bypasses a segment of an LED string in response to a sensed voltage level, as claimed in the ’836 patent?
• A Definitional Question of "Control": The case may turn on the construction of "control circuitry." The court will need to decide whether the term is defined by the specific function it performs (producing a shunt signal below a voltage threshold), potentially covering a wide array of circuits, or if it is implicitly limited by the specification to the specific resistor-divider and inverter embodiments disclosed.
• A Scope Question of Connectivity: The interpretation of the term "coupled directly" in Claim 1 will likely be a significant point of contention. The outcome of this construction could be dispositive if Defendant's products include any components—even minor ones—between the bridge rectifier output and the main LED string.