DCT
1:25-cv-01476
Luminatronics LLC v. Littelfuse Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Luminatronics LLC (Delaware)
- Defendant: Littelfuse, Inc. (Delaware)
- Plaintiff’s Counsel: Silverman, McDonald & Friedman; Rabicoff Law LLC
- Case Identification: 1:25-cv-01476, D. Del., 12/08/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is incorporated in Delaware and maintains an established place of business in the district.
- Core Dispute: Plaintiff alleges that Defendant’s unspecified products infringe a patent related to circuitry for driving Light Emitting Diode (LED) light structures.
- Technical Context: The technology addresses methods for improving the electrical efficiency and performance of LED lighting systems when powered by standard alternating current (AC) sources.
- Key Procedural History: The complaint does not reference any prior litigation, administrative patent challenges, or licensing history related to the patent-in-suit.
**Case Timeline**
| Date | Event |
|---|---|
| 2013-01-02 | ’836 Patent Priority Date |
| 2017-10-31 | ’836 Patent Issue Date |
| 2025-12-08 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,807,836 - *"Light emitting diode light structures"*
- Issued: October 31, 2017
- Alias: ’836 Patent
The Invention Explained
- Problem Addressed: The patent’s background section describes the inefficiency of powering a string of LEDs directly from a rectified AC power source ('836 Patent, col. 2:46-54). Because LEDs require a minimum voltage to turn on, they only draw current—and produce light—during the peak portions of the AC voltage cycle. This leads to a poor power factor and undesirable flicker, as the light output is not constant ('836 Patent, col. 2:56 - col. 3:5).
- The Patented Solution: The invention proposes a circuit that dynamically adjusts the length of the active LED string in response to the instantaneous voltage from the AC source ('836 Patent, Abstract). When the rectified voltage is below a certain threshold, control circuitry activates a switch that bypasses, or "shunts," a portion of the LED string. This allows the remaining, smaller group of LEDs to illuminate using the lower available voltage, enabling the light to draw current earlier and for a longer portion of the AC cycle ('836 Patent, col. 7:6-22; Fig. 6).
- Technical Importance: This approach aims to make the LED light bulb behave more like a purely resistive load to the AC power source, thereby improving the power factor and increasing the total light output over time without complex power conversion electronics ('836 Patent, col. 8:1-9).
Key Claims at a Glance
- The complaint asserts infringement of "one or more claims" without specifying which, instead referencing an external exhibit not attached to the pleading (Compl. ¶11). Independent claim 1 is representative of the core invention.
- Essential elements of Independent Claim 1:
- 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, the string having a first group of LEDs 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.
III. The Accused Instrumentality
Product Identification
- The complaint does not identify any specific accused products by name (Compl. ¶11). It refers generally to "Exemplary Defendant Products" that are purportedly identified in an "Exhibit 2," which was not filed with the complaint (Compl. ¶16).
Functionality and Market Context
- The complaint does not provide sufficient detail for analysis of the accused products' functionality or market position. It makes only conclusory allegations that the products "practice the technology claimed by the '836 Patent" (Compl. ¶16). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint’s infringement allegations are made entirely by reference to an unprovided exhibit (Compl. ¶17). Therefore, a direct analysis of the infringement theory is not possible from the provided documents. An infringement case would need to establish that the accused products contain circuitry corresponding to each element of an asserted claim, as outlined below for representative Claim 1.
’836 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a bridge rectifier configured to be powered by an alternating current power source and to produce a rectified output | The complaint does not specify the accused functionality. Plaintiff would need to show the accused products contain a circuit that converts AC to a rectified output. | ¶16 | col. 7:12-13 |
| control circuitry... configured to produce a shunt signal when the rectified output is less than a threshold voltage | The complaint does not specify the accused functionality. Plaintiff would need to identify a control circuit that generates a signal to activate a switch based on the level of the rectified voltage. | ¶16 | col. 7:13-18 |
| a series connected Light Emitting Diode (LED) string... having a first group of LEDs and a second group of LEDs | The complaint does not specify the accused functionality. Plaintiff would need to show the products contain an LED array organized as a string with at least two distinct groups. | ¶16 | col. 7:18-22 |
| a switch... controlled by the shunt signal to deactivate the second group of LEDs | The complaint does not specify the accused functionality. Plaintiff would need to identify a switching component (e.g., a transistor) that is controlled by the signal from the control circuitry to bypass the second group of LEDs. | ¶16 | col. 7:29-32 |
Identified Points of Contention
- Structural Questions: A primary question will be whether the accused products contain the specific structural arrangement claimed: a bridge rectifier, control circuitry, a divisible LED string, and a shunt switch operating in concert. The allegation that the LED string is "coupled directly to the bridge rectifier" may be contested if the accused products include significant intervening power conditioning components.
- Functional Questions: A key technical question will be how the accused products' circuitry operates. Does it generate a "shunt signal" that is responsive to a "threshold voltage" as claimed, or does it employ a different control logic for managing LED segments, such as a current-based or time-based system?
V. Key Claim Terms for Construction
**The Term: "deactivate the second group of LEDs"**
- Context and Importance: This term is critical as it defines the required outcome of the switch's operation. The dispute will likely center on whether the accused product's mechanism for bypassing or turning off a set of LEDs meets the definition of "deactivate."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain meaning of "deactivate" could encompass any method of rendering the LEDs non-operational or non-illuminating.
- Evidence for a Narrower Interpretation: The specification consistently describes the deactivation mechanism as a switch that "short out" or "shunts" the LEDs, effectively bypassing them ('836 Patent, col. 7:55-58). A defendant may argue that the term should be limited to this specific shunting embodiment, as depicted in Figure 6.
**The Term: "control circuitry"**
- Context and Importance: The scope of this term will determine what types of circuits can meet this limitation. As the complaint does not describe the accused circuitry, the breadth of this term will be a central issue. Practitioners may focus on this term because the patent discloses a specific implementation, which could be used to argue for a narrower construction.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Claim 1 recites the term functionally, requiring only that the circuitry be "configured to produce a shunt signal when the rectified output is less than a threshold voltage." This language may support a construction covering any circuit that performs this function.
- Evidence for a Narrower Interpretation: The detailed description discloses a specific embodiment comprising a "ratio metric series resistor string" and an "inverter" to generate the signal ('836 Patent, col. 7:16-18; col. 7:40-44). A defendant might argue that the term should be construed as limited to this structure or its equivalents.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement based on Defendant selling the accused products and distributing "product literature and website materials" that allegedly instruct end users to use the products in their "customary and intended manner that infringes" ('836 Patent, Compl. ¶¶14-15).
- Willful Infringement: The complaint does not contain a separate count for willful infringement but alleges that service of the complaint and its attached (but unprovided) claim charts "constitutes actual knowledge of infringement," forming a basis for potential post-filing willfulness (Compl. ¶13). No allegations of pre-suit knowledge are made.
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary issue will be one of evidentiary proof: given the complaint's lack of specificity, the case will first turn on discovering the exact design and operation of the accused products' LED driver circuitry. The viability of the infringement claim depends entirely on whether that circuitry maps onto the elements of the asserted claims.
- A central question of claim construction will be the scope of the term "deactivate." The dispute will likely focus on whether this term is limited to the shunting/bypassing mechanism described in the patent's embodiments or if it can read on other methods for turning off a segment of an LED string.
- A key technical question will be one of functional operation: does the accused product's circuitry in fact use a voltage-based threshold to control segments of the LED string, as required by the claims, or does it achieve power factor correction and flicker reduction through an alternative technical means that falls outside the patent's scope?