2:24-cv-06761
Signify Holding BV v. Keystone Tech LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Signify Holding B.V. (The Netherlands)
- Defendant: Keystone Technologies, LLC (Pennsylvania)
- Plaintiff’s Counsel: Alston & Bird LLP
- Case Identification: 1:24-cv-02401, N.D. Ga., 06/27/2024
- Venue Allegations: Plaintiff alleges venue is proper in the Northern District of Georgia because Defendant conducts regular business in the district, including operating a fulfillment center in Atlanta, employing a Territory Manager in Atlanta, and selling accused products that were purchased from and shipped into the district.
- Core Dispute: Plaintiff alleges that Defendant’s various LED lighting products, including area lights, downlights, replacement lamps, and retrofit kits, infringe a portfolio of nine patents related to LED driver circuitry, thermal and optical fixture design, and user-configurable lighting systems.
- Technical Context: The technology at issue falls within the field of solid-state (LED) lighting, a sector that has seen significant growth and innovation as it displaces traditional incandescent and fluorescent lighting technologies.
- Key Procedural History: The complaint alleges that Defendant had pre-suit knowledge of its alleged infringement of eight of the nine patents-in-suit via a series of notice letters dating back to February 2020. These allegations form the basis for claims of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 2005-11-25 | Earliest Priority Date ('577 Patent) |
| 2009-01-13 | Earliest Priority Date ('328 Patent) |
| 2011-11-22 | U.S. Patent No. 8,063,577 Issues |
| 2011-12-06 | U.S. Patent No. 8,070,328 Issues |
| 2012-09-25 | U.S. Patent No. 8,272,756 Issues |
| 2012-09-26 | Earliest Priority Date ('357 Patent) |
| 2016-02-19 | Earliest Priority Date ('300, '682, '350, '588 Patents) |
| 2016-05-24 | U.S. Patent No. 9,351,357 Issues |
| 2017-07-18 | U.S. Patent No. 9,709,253 Issues |
| 2017-11-14 | U.S. Patent No. 9,820,350 Issues |
| 2018-10-30 | U.S. Patent No. 10,117,300 Issues |
| 2019-12-10 | U.S. Patent No. 10,506,682 Issues |
| 2020-02-14 | Keystone allegedly receives notice of '577 and '357 Patents |
| 2021-06-28 | Keystone allegedly receives notice of '756, '300, and '350 Patents |
| 2022-08-09 | U.S. Patent No. 11,408,588 Issues |
| 2024-05-29 | Keystone allegedly receives notice of '328, '253, and '682 Patents |
| 2024-06-27 | Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,063,577 - "Method and a Driver Circuit for LED Operation"
The Invention Explained
- Problem Addressed: The patent describes a need for an LED driver circuit with higher efficiency than prior art designs, which it characterizes as suffering from low efficiency and requiring large filters or inductors due to their method of operation (e.g., hard-switched converters or duty-cycle control) (’577 Patent, col. 1:22-42).
- The Patented Solution: The invention proposes a driver circuit that uses a resonant capacitor in series with a transformer to generate an alternating supply current. This AC power is then rectified and buffered by an output circuit, which includes an inductor selected to provide a "substantially constant" current to the LEDs, aiming for high efficiency (’577 Patent, Abstract; col. 2:42-50).
- Technical Importance: The design focuses on improving the power conversion efficiency of LED drivers, a critical component for maximizing the energy-saving benefits of solid-state lighting.
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶47).
- The essential elements of claim 1 are:
- A driver circuit configured to control current to an LED.
- A set of input terminals for a supply voltage.
- A resonant capacitor.
- A transformer with its primary winding coupled in series with the resonant capacitor and input terminals.
- A rectifier means coupled to the transformer’s secondary winding.
- An output circuit receiving the rectified voltage, which includes a buffer circuitry comprising an inductor connected in series with the output terminals.
- The value of the inductor is selected to provide a substantially constant current through the LED.
- The complaint makes a general reservation of right to assert additional claims (Compl. ¶45).
U.S. Patent No. 8,070,328 - "LED Downlight"
The Invention Explained
- Problem Addressed: The patent addresses the challenge of creating an LED-based downlight that achieves the aesthetic and performance characteristics of traditional downlights, specifically a "clear cutoff with minimal glare" ( Compl. ¶19; ’328 Patent, col. 1:49-55).
- The Patented Solution: The patent discloses a fixture design centered on a "multi-piece reflector assembly" and a strategically placed diffuser. The assembly uses a first (upper) and second (lower) reflector to form a "light exit passageway," while a diffuser is positioned between them to soften and control the light output, thereby reducing glare (’328 Patent, Abstract; col. 5:5-45). The design also incorporates a heatsink for thermal management of the LED array.
- Technical Importance: This technology represents an approach to solving the optical design challenges inherent in adapting point-source LEDs for use in recessed downlighting applications where light quality and visual comfort are paramount.
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶66).
- The essential elements of claim 1 are:
- An LED downlight fixture.
- An array of LEDs thermally connected to a heatsink and positioned near a first aperture of a multi-piece reflector assembly.
- The multi-piece reflector assembly includes a first reflector with a first (upper) aperture and a larger second (lower) aperture.
- The assembly also includes a second reflector with apertures that align with the first reflector to define a light exit passageway.
- A diffuser is positioned "proximal to and extending across said second aperture of said first reflector and said first aperture of said second reflector."
- The complaint makes a general reservation of right to assert additional claims (Compl. ¶45).
U.S. Patent No. 8,272,756 - "LED-Based Lighting System and Method"
Technology Synopsis
The patent describes an LED lighting system built around an "integrated member," such as an aluminum extrusion, that serves as both a structural channel for the LEDs and a heat sink. The member includes a channel with a flat surface for mounting LEDs and external protrusions (fins) to dissipate heat (Compl. ¶20, ¶85).
Asserted Claims
Independent claim 1 (Compl. ¶83).
Accused Features
The Keystone Direct Drive HID Replacement LED Lamps are accused of infringing. The complaint alleges the lamp's body constitutes the claimed "integrated member" with a channel for the LEDs and protrusions for heat dissipation (Compl. ¶32, ¶87-89).
U.S. Patent No. 9,709,253 - "Light Emitting Diode Recessed Light Fixture"
Technology Synopsis
The patent discloses a recessed LED light fixture module designed for retrofitting into existing sockets. The key feature is an adapter that has a standard Edison screw-in plug on one end and a plug connector on the other, allowing the modern LED module to connect to a traditional Edison base (Compl. ¶21).
Asserted Claims
Independent claim 1 (Compl. ¶99).
Accused Features
The Keystone Aviva Retrofit Downlights are accused of infringement. The complaint alleges these products are downlight modules that include the claimed heat sink, LED light source, driver, and an adapter with an Edison screw-in plug for connecting to existing sockets (Compl. ¶33, ¶102-106).
U.S. Patent No. 9,351,357 - "Light Emitting Diode Lamp and Driver"
Technology Synopsis
The patent is directed to LED lamps designed to replace fluorescent tubes. The invention includes specific terminal and internal circuitry (rectifier, capacitor, fuses) configured to exchange a high-frequency (at least 1 kHz) alternating current signal with an electronic ballast, which replaces the traditional fluorescent ballast (Compl. ¶22, ¶118).
Asserted Claims
Independent claim 1 (Compl. ¶116).
Accused Features
The Keystone SmartDrive LED Lamps are accused of infringing. The complaint alleges these lamps are designed to be compatible with electronic ballasts and contain the specific two-pin terminal structure, rectifier, capacitor, and fuse configuration recited in the claim (Compl. ¶34, ¶120-128).
U.S. Patent No. 10,117,300 - "Configurable Lighting System"
Technology Synopsis
This patent describes a luminaire with a user-configurable "lumen control module." The module contains a multi-position switch coupled to a plurality of resistors, where each switch position selects a different resistance value, which in turn determines the current level supplied to the light source, thereby controlling its brightness (Compl. ¶23, ¶142).
Asserted Claims
Independent claim 1 (Compl. ¶139).
Accused Features
Several Keystone products (Aviva Downlight, Circa Slim Wafer Downlight, etc.) are accused of infringing. The complaint alleges these products contain a lumen control module with switches and resistors that allow users to select the lumen output (Compl. ¶141, ¶146).
U.S. Patent No. 10,506,682 - "Configurable Lighting System"
Technology Synopsis
Similar to the ’300 patent, this invention relates to a luminaire with a control module featuring a multi-position switch and resistive components for setting the current level. The claims specify that the light source illuminates regardless of the switch position, ensuring the light is always on when power is applied (Compl. ¶24, ¶160).
Asserted Claims
Independent claim 1 (Compl. ¶158).
Accused Features
The Keystone Advanta Downlight is accused of infringing. The complaint points to the product's "color select adjustment switch" as the claimed switch and alleges that the light source illuminates in any position of this switch, thereby meeting the claim limitations (Compl. ¶31, ¶162, ¶168).
U.S. Patent No. 9,820,350 - "Configurable Lighting System"
Technology Synopsis
The patent describes a configurable luminaire containing at least two different light sources (e.g., with different color temperatures). A user-settable input with multiple states controls a controller that can power the first light source, the second light source, or both, to produce various lighting effects (Compl. ¶25, ¶181).
Asserted Claims
Independent claim 1 (Compl. ¶178).
Accused Features
The Keystone Circa LED Slim Wafer Downlight is accused of infringing. The complaint alleges its "color select adjustment switch" is the claimed multi-state input that controls two distinct sets of LEDs (e.g., 2700K and 5000K) to produce different color temperatures by powering one, the other, or both sets (Compl. ¶35, ¶183-192).
U.S. Patent No. 11,408,588 - "Configurable Lighting System"
Technology Synopsis
This patent covers a lighting device with a first set of LEDs of a first color temperature and a second set of LEDs of a second color temperature. A switch controls the LEDs and includes a configuration that produces a third, intermediate color temperature by mixing light from both sets (Compl. ¶204).
Asserted Claims
Claim 21 (Compl. ¶202).
Accused Features
The Keystone Advanta Downlight is accused of infringing. The complaint alleges the product contains an array of cool white LEDs and an array of warm white LEDs, and that its "color select adjustment switch" has a setting that powers both arrays simultaneously to produce a mixed, intermediate color temperature (Compl. ¶31, ¶206-209).
III. The Accused Instrumentality
Product Identification
The complaint accuses multiple product lines, with specific exemplars identified for each patent. The lead accused products for the two fully analyzed patents are the Keystone XFIT Optics Swap LED Area Light (for the ’577 Patent) and the Advanta 8" Downlight (for the ’328 Patent) (Compl. ¶30, ¶31).
Functionality and Market Context
The accused products are commercial LED lighting fixtures, including outdoor area lights, recessed downlights for interior use, and various replacement lamps and retrofit kits (Compl. ¶30-35). The complaint alleges these products incorporate infringing technologies related to their electronic drivers, mechanical and thermal construction, and user-selectable features for brightness and color temperature. An annotated photograph of the Advanta Downlight shows its primary components, including a heatsink, an array of LEDs, and a multi-part reflector assembly (Compl. ¶70, p. 32). The complaint alleges these products are sold through distributors such as Grainger and that Keystone operates a fulfillment center in Atlanta to serve the Georgia market (Compl. ¶6, ¶7).
IV. Analysis of Infringement Allegations
U.S. Patent No. 8,063,577 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A driver circuit... configured to control a current to be supplied to the LED... | The accused XFIT Area Light includes a driver (KTLD-320-UV-A7600-56-VDIM-LW13) configured to control current to its LEDs. | ¶50 | col. 2:15-18 |
| a set of input terminals for receiving a supply voltage; | The accused driver allegedly includes input terminals for receiving a supply voltage, identified in a circuit diagram. | ¶51 | col. 3:20-24 |
| a resonant capacitor; | The accused driver allegedly includes a resonant capacitor, identified as C37 in a circuit diagram. | ¶52 | col. 3:21-22 |
| a transformer, a primary winding of the transformer and the resonant capacitor being coupled in series to the set of input terminals, | The accused driver allegedly includes a transformer (T2A) whose primary winding is coupled in series with the resonant capacitor. | ¶53 | col. 3:22-25 |
| a rectifier means coupled to the secondary winding of the transformer... | The accused driver allegedly includes a rectifier (diodes MBR30L150) coupled to the secondary winding of the transformer. | ¶54 | col. 3:36-39 |
| an output circuit... comprising a buffer circuitry... wherein the buffer circuitry comprises an inductor... and the value of the inductor is selected to provide a substantially constant current through the LED. | The accused driver allegedly includes an output circuit with buffer circuitry containing an inductor (LF3) connected in series with the output terminals. The complaint alleges the inductor's value is selected to provide a substantially constant current, noting the driver is marketed as a "CONSTANT CURRENT" driver. | ¶55, ¶56 | col. 4:22-29 |
Identified Points of Contention
- Scope Questions: A central question may be the construction of "substantially constant current." While the complaint alleges the accused product is a "CONSTANT CURRENT" driver (Compl. ¶56), litigation may focus on whether the degree of current ripple or fluctuation in the accused device falls within the scope of "substantially constant" as understood from the patent's specification and prosecution history.
- Technical Questions: The complaint's allegations are based on an analysis of the accused driver's circuit diagram (referenced as Exhibit 21) (Compl. ¶51-56). The factual accuracy of that analysis—whether the identified components function as the claimed elements—will be a key technical question. The assertion that the inductor's value "is selected" to provide constant current raises an evidentiary question about the design intent versus the mere operational result.
U.S. Patent No. 8,070,328 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An LED downlight fixture... | The accused Advanta Downlight is identified as an LED downlight fixture. | ¶69 | col. 4:40-41 |
| an array of LEDs in thermal connectivity with a heatsink, said array of LEDs positioned adjacent a first aperture of a multi-piece reflector assembly: | The complaint provides an annotated photograph showing an array of LEDs on a board connected to a heatsink and positioned over an aperture in the reflector assembly. | ¶70 | col. 5:1-4 |
| said multi-piece reflector assembly including: a first reflector having said first aperture... and an opposed larger second aperture... | An annotated photograph purports to show a "first reflector" with a smaller upper "first aperture" and a larger lower "second aperture." | ¶71 | col. 5:7-14 |
| a second reflector having a first aperture positioned adjacent said second aperture of said first reflector and a second aperture... defining a light exit passageway; | An annotated, exploded-view photograph purports to show a separate "second reflector" that aligns with the first reflector to form the light exit. | ¶72 | col. 5:22-28 |
| a diffuser positioned proximal to and extending across said second aperture of said first reflector and said first aperture of said second reflector. | An annotated photograph purports to show a "diffuser" positioned to cover the opening between the alleged first and second reflectors. | ¶73 | col. 5:36-45 |
Identified Points of Contention
- Scope Questions: The infringement analysis will likely turn on the construction of the structural terms. A dispute may arise over whether the accused product contains a "multi-piece reflector assembly" or an integrated component. Further, the precise location defined by "diffuser positioned proximal to and extending across said second aperture of said first reflector and said first aperture of said second reflector" will be critical, as any deviation in the accused product's structure could be a basis for a non-infringement argument.
- Technical Questions: The complaint's case rests heavily on annotated photographs of the accused product (Compl. ¶70-73). A key question will be whether these photographs accurately depict distinct components that meet each structural limitation. For example, what evidence demonstrates that the components labeled "first reflector" and "second reflector" are in fact separate pieces that form an "assembly" as required by the claim? An annotated photograph in the complaint shows the two reflector components separated, suggesting they are distinct parts (Compl. ¶72, p. 34).
V. Key Claim Terms for Construction
U.S. Patent No. 8,063,577
- The Term: "substantially constant current"
- Context and Importance: This term defines the required performance of the claimed driver circuit's output stage. The defendant may argue that its driver's output current has fluctuations that remove it from the scope of "substantially constant," while the plaintiff may point to the defendant's own characterization of the product as a "CONSTANT CURRENT" driver as an admission that it meets the limitation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the goal of providing a "substantially constant load current" but does not define a specific numerical tolerance for current ripple or variation (e.g., ’577 Patent, col. 2:48-50). This lack of specificity could support a broader reading that encompasses typical constant current drivers in the field.
- Evidence for a Narrower Interpretation: The patent figures include a waveform diagram (FIG. 3c) that illustrates the resulting load current as a relatively smooth, flat line. A defendant could argue that this depiction implicitly defines the required degree of "constancy," limiting the claim to circuits that achieve a similarly low level of ripple.
U.S. Patent No. 8,070,328
- The Term: "multi-piece reflector assembly"
- Context and Importance: This term is foundational to the claimed structure. Infringement requires the accused product to have at least two separate reflector components that work together. If the accused product's reflector is a single, integrated piece, it would not infringe. Practitioners may focus on this term because the complaint's allegations depend on the physical separability of the parts identified as the "first reflector" and "second reflector" (Compl. ¶71, ¶72).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent repeatedly refers to a "first reflector" and a "second reflector" as distinct components of the "assembly" (’328 Patent, col. 5:5-28). The plain meaning of "multi-piece" suggests more than one part, which could be broadly interpreted as any construction not made of a single, monolithic piece.
- Evidence for a Narrower Interpretation: The detailed description and figures show a specific arrangement where an "upper reflector 52" and a "lower reflector 54" are distinct parts, with the lower reflector potentially including a mounting ring for a diffuser (’328 Patent, Fig. 3; col. 5:36-39). A defendant might argue that "assembly" implies not just multiple pieces, but pieces that are assembled in the specific manner and relationship disclosed in the patent's embodiments.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. The inducement allegations are based on Defendant’s alleged marketing, instructions, and technical support that encourage infringing uses (e.g., Compl. ¶59, ¶76). The contributory infringement allegations assert that the accused products or key components thereof are not staple articles of commerce and are especially made or adapted for use in an infringing manner (e.g., Compl. ¶60, ¶77).
- Willful Infringement: The complaint alleges willful infringement for all asserted patents based on Defendant’s alleged continued infringement after receiving notice. For eight of the nine patents, this notice was allegedly provided via letters sent pre-suit, with the earliest notice dating to February 14, 2020 (Compl. ¶36-38, ¶61, ¶78). For the ’588 Patent, knowledge is alleged from the filing of the complaint itself (Compl. ¶211).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of definitional scope and structure: Can the functional term "substantially constant current" in the ’577 Patent be construed to read on the actual output of the accused driver, and do the physical components of the accused Advanta Downlight constitute a "multi-piece reflector assembly" with a "diffuser" positioned in the precise location required by the ’328 Patent?
- A second core issue relates to operational equivalence for the configurable patents: Do Keystone’s products, which use dip switches for "Power Select" and "Color Select" functionalities, implement the specific control logic, switch-and-resistor circuits, and multi-light-source configurations recited in the claims of the '300, '682, '350, and '588 patents, or is there a fundamental mismatch in their technical operation?
- A key question for damages will be willfulness: Given the series of pre-suit notice letters alleged in the complaint, did the Defendant act with objective recklessness by continuing to sell the accused products, potentially exposing it to enhanced damages for a substantial portion of the accused sales?