DCT

3:25-cv-05637

Seoul Semiconductor Co Ltd v. BFG Supply Co LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:25-cv-05637, W.D. Wash., 07/22/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Western District of Washington because Defendant BFG Supply Co. operates a regular and established place of business in Fife, Washington, from which it allegedly completes infringing sales within the district.
  • Core Dispute: Plaintiffs allege that Defendant’s horticultural LED lighting products infringe eight patents related to various aspects of LED technology, including device architecture, spectral output, packaging, and internal semiconductor structures.
  • Technical Context: The technology domain is high-performance light-emitting diodes (LEDs), specifically as applied in horticultural lighting systems where precise control over the light spectrum is critical for optimizing plant growth.
  • Key Procedural History: The complaint alleges that on June 20, 2025, approximately one month prior to filing suit, Plaintiff Seoul Semiconductor sent a warning letter to Defendant BFG, which included claim charts demonstrating the alleged infringement. This pre-suit notification is cited as a basis for willful infringement.

Case Timeline

Date Event
2006-12-26 U.S. Patent No. 8,872,419 Priority Date
2010-12-24 U.S. Patent No. 8,314,440 Priority Date
2011-06-02 U.S. Patent No. 9,041,032 Priority Date
2012-07-02 U.S. Patent No. 10,217,912 Priority Date
2012-11-20 U.S. Patent No. 8,314,440 Issue Date
2014-10-28 U.S. Patent No. 8,872,419 Issue Date
2015-05-26 U.S. Patent No. 9,041,032 Issue Date
2017-07-27 U.S. Patent No. 12,194,174 Priority Date
2017-08-21 U.S. Patent No. 11,978,837 Priority Date
2018-09-14 U.S. Patent No. 12,298,552 Priority Date
2018-12-07 U.S. Patent No. 12,274,893 Priority Date
2019-02-26 U.S. Patent No. 10,217,912 Issue Date
2024-05-07 U.S. Patent No. 11,978,837 Issue Date
2025-01-14 U.S. Patent No. 12,194,174 Issue Date
2025-04-15 U.S. Patent No. 12,274,893 Issue Date
2025-05-13 U.S. Patent No. 12,298,552 Issue Date
2025-06-20 Pre-suit notice letter sent to Defendant
2025-07-22 Complaint Filing Date

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

U.S. Patent No. 12,274,893 - "LED Lighting Apparatus Having Sterilizing Function"

  • Patent Identification: U.S. Patent No. 12,274,893, “LED Lighting Apparatus Having Sterilizing Function,” issued April 15, 2025.

The Invention Explained

  • Problem Addressed: The patent describes combining different types of light-emitting diodes to create a lighting apparatus with a specific, tailored spectral output that may have functions beyond simple illumination, such as a "cell activating function" (Compl. ¶1; ’893 Patent, col. 1:15-24).
  • The Patented Solution: The invention is a lighting apparatus that combines a "white light emitting device"—itself composed of a primary light emitter (e.g., a blue LED) and a wavelength converter (e.g., phosphors)—with a "second light emitting diode" that produces light in a different spectral range, such as red (605 nm to 935 nm). A key claimed feature is that in the resulting light spectrum, the irradiance contribution from the second (red) diode is greater than that from the white light device at the same wavelength, ensuring the properties of the red light are prominent in the combined output (’893 Patent, Abstract; col. 2:5-24).
  • Technical Importance: This design allows for the creation of customized light spectra beneficial for applications like horticulture, where specific ratios of blue and red light are critical for plant photosynthesis and growth (’893 Patent, Abstract).

Key Claims at a Glance

  • The complaint asserts infringement of at least exemplary Claim 1 (Compl. ¶24).
  • The essential elements of independent Claim 1 include:
    • A white light emitting device comprising a first light emitter and a wavelength converter.
    • A second light emitter emitting light at a different peak wavelength.
    • A controller to control both light emitters.
    • The first light emitter emits blue light, the second emits light between 605-935 nm, and the combined white light device emits light between 430-470 nm.
    • A specific spectral relationship where the irradiance from the second emitter is greater than that from the white light emitting device at the same wavelength.
  • The complaint reserves the right to assert additional claims (Compl. ¶28).

U.S. Patent No. 8,872,419 - "Light emitting device"

  • Patent Identification: U.S. Patent No. 8,872,419, “Light emitting device,” issued October 28, 2014.

The Invention Explained

  • Problem Addressed: The patent background describes conventional methods for creating white light, such as using a blue LED with a phosphor or mixing light from red, blue, and green LEDs. The implicit problem is the difficulty in achieving a high Color Rendering Index (CRI), as many phosphor-converted white LEDs are deficient in the red portion of the spectrum (’419 Patent, col. 1:21-44).
  • The Patented Solution: The invention is a light emitting device that combines a "first light emitting element" (a standard package with a chip and phosphor) with an adjacent "second light emitting element" (a chip without a phosphor) that emits light in the yellow-to-red spectrum (560 to 880 nm). The two distinct elements are connected in parallel on a circuit board (’419 Patent, Abstract; col. 2:1-7).
  • Technical Importance: This architecture allows a manufacturer to supplement the spectrum of a standard white LED with a specific red component, which can significantly improve the CRI and make illuminated objects appear more natural (’419 Patent, col. 2:50-60).

Key Claims at a Glance

  • The complaint asserts infringement of at least exemplary Claim 1 (Compl. ¶38).
  • The essential elements of independent Claim 1 include:
    • At least one first light emitting element comprising a light emitting chip and a phosphor.
    • At least one second light emitting element disposed adjacent to the first element, emitting light with a wavelength of 560 to 880 nm.
    • The first light emitting element is connected in parallel with the second light emitting element.
  • The complaint reserves the right to assert additional claims (Compl. ¶38).

U.S. Patent No. 12,194,174 - "Lighting device"

  • Patent Identification: U.S. Patent No. 12,194,174, “Lighting device,” issued January 14, 2025.
  • Technology Synopsis: This patent addresses the physical arrangement of different types of LEDs on a lighting device. The claimed invention involves a housing where a first light source and a second light source are disposed on a bottom surface, but their respective light-emitting surfaces are at different elevations relative to that bottom surface (’174 Patent, Abstract).
  • Asserted Claims: At least exemplary Claim 14 (Compl. ¶52).
  • Accused Features: The complaint alleges that the accused Gavita CT and Pro RS products have a housing on which white LEDs and red LEDs are disposed, with the light emitting surface of the red LED being at a different elevation from that of the white LED (Compl. ¶57, 63).

U.S. Patent No. 11,978,837 - "Light emitting diode package"

  • Patent Identification: U.S. Patent No. 11,978,837, “Light emitting diode package,” issued May 7, 2024.
  • Technology Synopsis: This patent details the internal structure of an LED chip package designed to improve light extraction efficiency. The invention includes a reflective layer, such as one containing aluminum, disposed on the semiconductor chip's surface and positioned between the chip and its covering encapsulation to reflect light upwards (’837 Patent, col. 2:7-21).
  • Asserted Claims: At least exemplary Claim 8 (Compl. ¶68).
  • Accused Features: The complaint alleges, based on scanning electron microscope (SEM) and focused ion beam (FIB) analysis, that the LED chips in the accused products contain a reflective aluminum layer under the p-contact and between the chip and the encapsulation (Compl. ¶76, 84).

U.S. Patent No. 12,298,552 - "Backlight unit and display apparatus having the same"

  • Patent Identification: U.S. Patent No. 12,298,552, “Backlight unit and display apparatus having the same,” issued May 13, 2025.
  • Technology Synopsis: This patent relates to the physical and electrical layout of components on the substrate of a light source. The claimed invention specifies that a first pad electrode and a second pad electrode on the substrate, which are connected to the light emitter, are spaced apart from each other by at least 50 micrometers (’552 Patent, Abstract).
  • Asserted Claims: At least exemplary Claim 15 (Compl. ¶88).
  • Accused Features: The complaint alleges that analysis of the accused Gavita CT product reveals pad electrodes on the circuit board substrate with a gap greater than 50 micrometers (Compl. ¶96).

U.S. Patent No. 8,314,440 - "Light emitting diode chip and method of fabricating the same"

  • Patent Identification: U.S. Patent No. 8,314,440, “Light emitting diode chip and method of fabricating the same,” issued November 20, 2012.
  • Technology Synopsis: This patent describes a specialized reflective structure on the bottom of an LED chip's substrate. The invention consists of an "alternating lamination bottom structure" made of multiple dielectric pairs, where each pair has layers of different materials and specific optical thicknesses relative to the wavelength of light (λ), such as less than or greater than λ/4, to create a highly reflective surface (’440 Patent, Abstract).
  • Asserted Claims: At least exemplary Claim 1 (Compl. ¶100).
  • Accused Features: The complaint alleges that SEM images of the accused Gavita Pro RS LED chips show an alternately laminated bottom structure comprising dielectric pairs with the claimed optical thickness characteristics (Compl. ¶103).

U.S. Patent No. 10,217,912 - "Light emitting diode module for surface mount technology and method of manufacturing the same"

  • Patent Identification: U.S. Patent No. 10,217,912, “Light emitting diode module for surface mount technology and method of manufacturing the same,” issued February 26, 2019.
  • Technology Synopsis: This patent concerns the electrical isolation and connection within an LED chip. The invention describes an insulation layer formed over the semiconductor structure which has openings, allowing a separate reflective layer (e.g., aluminum) to make contact with the semiconductor layer only at specific, exposed portions (’912 Patent, col. 2:5-18).
  • Asserted Claims: At least exemplary Claim 1 (Compl. ¶107).
  • Accused Features: The complaint alleges that SEM analysis of the accused products' LED chips reveals an insulation layer over the stacked semiconductor structure that leaves portions exposed for contact with an aluminum reflective layer (Compl. ¶110, 113).

U.S. Patent No. 9,041,032 - "Light emitting diode having strain-enhanced well layer"

  • Patent Identification: U.S. Patent No. 9,041,032, “Light emitting diode having strain-enhanced well layer,” issued May 26, 2015.
  • Technology Synopsis: This patent details a specific composition for the light-generating active layer within a semiconductor. The invention claims an active layer that includes barrier layers and well layers, where the barrier layers contain AlGaN-based quantum dots that form a "strain enhancing layer" to provide compressive strain to the well layer, which can improve efficiency (’032 Patent, Abstract).
  • Asserted Claims: At least exemplary Claim 19 (Compl. ¶117).
  • Accused Features: The complaint alleges that SEM analysis of the Gavita Pro RS LEDs reveals an active layer composed of AlGaN barrier layers and InGaN well layers, with the barrier layers containing AlGaN-based quantum dots that form a strain enhancing layer (Compl. ¶120).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are the “Gavita Pro RS 2400e LED 208-480V” (“Gavita Pro RS”) and the “Gavita CT 2000e LED 208-480V” (“Gavita CT”) (Compl. ¶¶2, 38).

Functionality and Market Context

  • The accused products are LED-based lighting apparatuses marketed as horticultural grow lights (Compl. ¶25, 30). The complaint alleges that the products incorporate multiple types of LEDs to produce a full spectrum of light suitable for plant growth, specifically combining white LEDs (which appear yellow due to phosphor converters) and distinct red LEDs on light bars or panels (Compl. ¶26, 31, 40). An image in the complaint shows a light bar from an accused product with distinct yellow-appearing white LEDs and red LEDs arranged adjacently (Compl. ¶45, p. 14). The products are allegedly intended to be operated with a separate "Gavita® Master EL3 Controller" (Compl. ¶29).

IV. Analysis of Infringement Allegations

'893 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a white light emitting device including at least one first light emitter and a wavelength converter to implement white light; The accused products include white light emitting devices comprising blue-light emitting LEDs covered by a yellow wavelength converter. An image shows the blue LEDs after removal of the converter. ¶27 col. 2:5-8
at least one second light emitter configured to emit light having a peak wavelength...in a range of about 605 nm to about 935 nm; The accused products include red LEDs with a peak wavelength within the 605 to 935 nanometer range. ¶28 col. 2:14-16
a controller configured to control the white light emitting device and the at least one second light emitter, Defendant instructs purchasers to operate the accused products using the “Gavita® Master EL3 Controller,” which is identified as a lighting controller. ¶29 col. 2:5-8
the light emitted by the at least one second light emitter includes a region in an irradiance spectrum having an irradiance that is greater than an irradiance of light emitted from the white light emitting device at a same wavelength. The light emitted by the red LED allegedly has an irradiance greater than that of the light from the white light emitting device at the same wavelength. ¶28; p. 9, ¶1-2 col. 2:17-24

'419 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
at least one first light emitting element comprising at least one light emitting chip and a phosphor; The accused products include a first light emitting element comprising at least one light emitting chip and a yellow phosphor containing encapsulant. An image shows the white LED package before and after removal of the phosphor. ¶41; ¶46 col. 2:1-3
at least one second light emitting element disposed adjacent to the first light emitting element to emit light having a wavelength of 560 to 880 nm; The accused products contain red LEDs (a second light emitting element) disposed adjacent to the white LEDs (the first light emitting element). An image shows the adjacent placement of the two different types of LEDs. ¶40; ¶42; ¶45 col. 2:3-5
and the first light emitting element is connected in parallel with the second light emitting element. An x-ray image of the accused product's circuitry allegedly shows that the second light emitting element (red LED) is connected in parallel with the first light emitting element (white LED). ¶43; ¶48 col. 2:6-7

Identified Points of Contention

  • Scope Questions: A primary question for the ’893 Patent will concern the "controller" limitation. Does the term "lighting apparatus" as used in the patent encompass a system that includes a separately sold but required controller, as alleged by the Plaintiff? Or is the "apparatus" limited to the lighting fixture itself, which may not contain the claimed controller?
  • Technical Questions: For the ’419 Patent, a central issue may be whether the electrical configuration in the accused products constitutes a "parallel" connection as that term is used and defined within the patent. The complaint's infringement theory rests on an X-ray image of the product's wiring (Compl. ¶43, p. 13); the accuracy of this depiction and its satisfaction of the claim term will be a key factual dispute. For the patents concerning microscopic internal structures (e.g., '837, '440, '912, '032), a question will be whether the evidence from the complaint's reverse engineering analyses is sufficient to prove that the highly specific layered structures of the claims are present in the mass-produced accused products.

V. Key Claim Terms for Construction

Term: "lighting apparatus" ('893 Patent, Claim 1)

  • Context and Importance: The construction of this term is central to the infringement analysis of the '893 patent. The complaint alleges that the accused lighting fixtures, in combination with the separately sold "Gavita® Master EL3 Controller," meet the limitations of the claim. Practitioners may focus on this term because its scope will determine whether the "controller" limitation can be met by an external, albeit necessary, component.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent's summary describes the invention as a "lighting apparatus" and a "lighting system" (col. 2:28-32), which could suggest that the term encompasses multiple coordinated components.
    • Evidence for a Narrower Interpretation: The detailed descriptions and figures (e.g., Fig. 12) may depict embodiments where the controller is an integrated component of a single physical unit, potentially supporting an interpretation that limits the "apparatus" to a standalone device.

Term: "connected in parallel" ('419 Patent, Claim 1)

  • Context and Importance: This term defines the required electrical relationship between the two different types of light emitting elements. The complaint provides an X-ray image allegedly showing this parallel connection (Compl. ¶43, p. 13). The viability of the infringement claim for the '419 patent hinges on whether the accused product's circuit topology falls within the proper construction of this term.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent may use the term consistent with its ordinary meaning in electrical engineering without adding further limitations, which would cover any standard parallel circuit configuration.
    • Evidence for a Narrower Interpretation: The specification or figures (e.g., Fig. 3, 7) illustrate specific circuit diagrams. A defendant may argue that these embodiments define the term more narrowly, potentially excluding the specific wiring configuration found in the accused products if it differs in any material way.

VI. Other Allegations

Indirect Infringement

  • The complaint alleges induced infringement, stating that Defendant instructs purchasers to operate the accused lighting fixtures with the separately sold "Gavita® Master EL3 Controller" (Compl. ¶29, 34). This allegation is aimed at satisfying the "controller" limitation of the '893 patent, suggesting that even if the fixture alone does not directly infringe, Defendant induces its customers to create an infringing system.

Willful Infringement

  • The complaint alleges willful infringement for all asserted patents. The basis for this allegation is pre-suit knowledge, stemming from a warning letter with attached claim charts sent to Defendant on June 20, 2025, and Defendant's alleged continuation of infringing sales after receiving this notice (Compl. ¶18, 20, 36, 50, 66).

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

  • A core issue will be one of system scope: can the term “lighting apparatus,” as claimed in the '893 patent, be construed to cover a system comprising a lighting fixture and a separately sold controller? The outcome of this question may determine the viability of infringement for at least one of the asserted patents.
  • A key evidentiary question will be one of microscopic correspondence: the complaint makes numerous allegations regarding the highly specific, internal nanostructures of the accused LED chips, supported by sophisticated SEM, FIB, and X-ray imaging. The case will likely turn on whether this reverse-engineering evidence is sufficient to prove, on a balance of probabilities, that the mass-produced accused products consistently contain the precise layered and spaced structures required by the '837, '552, '440, '912, and '032 patents.
  • A central technical question will be one of circuit equivalence: for the '419 patent, does the electrical wiring within the accused products, as depicted by the complaint’s X-ray imagery, implement the specific “parallel” connection required by the claim, or is there a functional or structural difference that places it outside the claim's scope?