DCT
5:24-cv-00031
Feit Electric Co Inc v. Ledvance LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Feit Electric Company, Inc. (California)
- Defendant: Ledvance, LLC (Delaware)
- Plaintiff’s Counsel: Dinsmore & Shohl LLP; Benesch Friedlander Coplan & Aronoff LLP
- Case Identification: 5:24-cv-00031, E.D. Ky., 02/02/2024
- Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Kentucky because Defendant Ledvance has its principal place of business in the district, transacts business there, and has committed alleged acts of patent infringement within the district.
- Core Dispute: Plaintiff alleges that Defendant’s SYLVANIA brand "White Filament" LED light bulbs infringe a patent related to wavelength conversion components that use a distinct diffusing layer to improve the aesthetic appearance of the LED, particularly its color when turned off.
- Technical Context: The technology addresses the consumer-facing aesthetics of LED lighting, where the typically yellow or orange appearance of phosphor-coated components in their "off-state" can be commercially undesirable.
- Key Procedural History: The complaint alleges that Plaintiff sent a notice letter to Defendant on December 12, 2023, identifying the patent-in-suit and the accused products. This letter forms the basis for the willfulness allegations. The patent-in-suit is subject to a terminal disclaimer.
Case Timeline
| Date | Event |
|---|---|
| 2010-10-05 | U.S. Patent No. 8,604,678 Priority Date |
| 2013-12-10 | U.S. Patent No. 8,604,678 Issue Date |
| 2023-12-12 | Plaintiff allegedly sent notice letter to Defendant |
| 2023-12-18 | Notice letter allegedly delivered to Defendant |
| 2024-01-23 | Plaintiff allegedly purchased samples of Accused Products |
| 2024-02-02 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,604,678 - "Wavelength Conversion Component With a Diffusing Layer"
- Patent Identification: U.S. Patent No. 8,604,678, titled “Wavelength Conversion Component With a Diffusing Layer,” issued December 10, 2013.
The Invention Explained
- Problem Addressed: The patent's background section describes two primary issues with prior art LED lighting devices that use "remote phosphor" components. First, when the device is in its "OFF state," the phosphor gives it a "yellowish, yellow-orange, or orange-color appearance" that may be "undesirable to the potential purchasers" seeking a white-appearing light bulb (ʼ678 Patent, col. 2:7-17). Second, these devices can exhibit "variation in color of emitted light with emission angle" when in use (ʼ678 Patent, col. 2:18-22).
- The Patented Solution: The invention is a wavelength conversion component that comprises two distinct but adjacent layers: a "wavelength conversion layer" containing photoluminescent material (e.g., phosphor) and a separate "light diffusing layer" containing light-scattering particles (e.g., titanium dioxide) (ʼ678 Patent, Abstract; col. 3:1-14). This dual-layer structure is designed to mask the phosphor's off-state color, making the component appear white, while also improving the uniformity of the emitted light when the device is on (ʼ678 Patent, col. 2:48-51; col. 3:15-24). Figure 2 of the patent illustrates this layered structure, showing the light diffusing layer (44) and the wavelength conversion layer (46) on a substrate (42) (ʼ678 Patent, Fig. 2).
- Technical Importance: This approach addresses an aesthetic and commercial hurdle for certain LED technologies by making their appearance more consistent with traditional incandescent bulbs, regardless of whether they are powered on or off (ʼ678 Patent, col. 2:11-17).
Key Claims at a Glance
- The complaint asserts at least independent claim 1.
- The essential elements of independent claim 1 include:
- A wavelength conversion component for a light emitting device comprising:
- a wavelength conversion layer comprising particles of at least one photoluminescence material;
- and a light diffusing layer comprising particles of a light scattering material,
- wherein the light diffusing layer improves an off-state white appearance of the wavelength conversion component;
- wherein the wavelength conversion component is configured such that in operation a portion of excitation light comprising blue light (wavelength ≥ 440 nm) is emitted through the component to contribute to the final visible emission product.
III. The Accused Instrumentality
Product Identification
- The complaint identifies twelve models of SYLVANIA brand lamps, such as candelabra, A19, ST19, and G25 style bulbs, that are marketed as having a "WHITE FILAMENT" (Compl. ¶13, ¶16). Accused Product No. 1 is Model LED3.5B10CDIM827FILWHRP40184 (Compl. ¶19).
Functionality and Market Context
- The Accused Products are described as "LED filament lamps" that comprise light emitting diodes on a substrate, covered by a light conversion material, and housed within a lamp enclosure (Compl. ¶18). The complaint highlights the product packaging, which explicitly contrasts its "WHITE FILAMENT" with a "YELLOW FILAMENT" and states that the product "Looks Great Off or On" (Compl. ¶16). The complaint alleges this marketing directly corresponds to the functionality claimed in the ʼ678 Patent (Compl. ¶19). The complaint provides an image of the packaging for one of the accused candelabra bulbs, which promotes the aesthetic benefit of the white filament (Compl. ¶16).
IV. Analysis of Infringement Allegations
U.S. Patent No. 8,604,678 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a wavelength conversion layer comprising particles of at least one photoluminescence material; | The complaint alleges, based on visual inspection, that a yellow material within the filament is a wavelength conversion layer containing a phosphor mixed in a silicone carrier. A photograph with a red arrow points to this alleged layer (Compl. ¶19). | ¶19 | col. 8:56-65 |
| and a light diffusing layer comprising particles of a light scattering material, | The complaint alleges that a white material shown in a close-up photograph of the filament is a light diffusing layer containing a light scattering material, such as titanium dioxide, mixed in a silicone carrier. A separate photograph with a blue arrow points to this alleged layer (Compl. ¶19). | ¶19 | col. 8:19-24 |
| wherein the light diffusing layer improves an off-state white appearance of the wavelength conversion component; | The complaint alleges the off-state appearance of the accused LED filament is white, rather than the typical yellow of phosphor material, and points to side-by-side photographs of the accused product's white filament next to a traditional yellow filament (Compl. ¶19). The complaint further cites the product's packaging, which claims it "Looks Great Off or On," as an admission that this feature is an improvement (Compl. ¶19). | ¶19 | col. 11:19-24 |
| wherein the wavelength conversion component is configured such that in operation a portion of excitation light comprising blue light...is emitted through the wavelength conversion component to contribute to a final visible emission product. | The complaint alleges on information and belief that when powered, the LEDs emit blue light (≥ 440 nm) which is converted by the wavelength conversion layer to white light, and this light then passes through the light diffusing layer. A photograph shows the accused product illuminated and emitting visible light (Compl. ¶19). | ¶19 | col. 10:28-44 |
- Identified Points of Contention:
- Structural Question: The complaint’s infringement theory relies on photographs that appear to show two distinct materials on the LED filament. A central technical question will be whether discovery and expert analysis confirm the existence of two separate and distinct layers corresponding to the claimed "wavelength conversion layer" and "light diffusing layer", or if the filament is composed of a single, integrated mixture of phosphor and scattering particles. The physical structure and composition of the filament will be a primary focus.
- Functional Question: The complaint uses the defendant's marketing slogan, "Looks Great Off or On," as evidence that the accused product meets the "improves an off-state white appearance" limitation. A point of contention may be whether this marketing claim is a sufficient proxy for the technical function required by the claim, or if objective, empirical evidence (e.g., colorimetric data) is necessary to prove this limitation is met.
V. Key Claim Terms for Construction
The Term: "light diffusing layer"
Context and Importance: The existence of a distinct "light diffusing layer" separate from the "wavelength conversion layer" is a cornerstone of the patented invention. The construction of this term will determine whether a component with scattering and phosphor materials blended into a single matrix would fall within the claim scope, or if two physically distinct layers are required. Practitioners may focus on this term because the complaint's visual evidence suggests two materials, but their precise structural relationship as distinct "layers" is a matter for factual determination.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim requires the layer to "compris[e] particles of a light scattering material," which does not, on its face, exclude the presence of other materials like phosphor.
- Evidence for a Narrower Interpretation: The patent consistently illustrates the "light diffusing layer" (44) and "wavelength conversion layer" (46) as two separate, adjacent structures (ʼ678 Patent, Fig. 2; col. 3:9-14). Dependent claim 2 further specifies that the two layers are in "direct contact with each other," which reinforces the concept that they are two separate entities that touch at an interface, not a single commingled substance (ʼ678 Patent, col. 26:27-29).
The Term: "improves an off-state white appearance"
Context and Importance: This is a functional limitation that defines the purpose and result of the "light diffusing layer". Its construction is critical because it sets the standard for infringement. The dispute will likely focus on how "improves" and "white appearance" are measured—subjectively, or by an objective, quantifiable standard.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent's background frames the problem as avoiding a "yellowish, yellow-orange, or orange-color appearance" that is "off-putting or undesirable" to consumers (ʼ678 Patent, col. 2:9-16). This could support a construction where any measurable color shift away from yellow and towards white, which a consumer would perceive as an improvement, meets the limitation.
- Evidence for a Narrower Interpretation: The term lacks a precise colorimetric definition within the patent. A defendant could argue that without an objective standard (e.g., a specific range on a CIE chromaticity diagram), the term is indefinite. The specification’s focus on solving the "non-white color appearance" could suggest that a mere reduction in yellowness is insufficient if the resulting color is not perceived as "white." (ʼ678 Patent, col. 1:64-65).
VI. Other Allegations
- Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge. It states that Plaintiff sent a notice letter via FedEx on December 12, 2023, which was delivered to Defendant's General Counsel on December 18, 2023 (Compl. ¶¶ 24-25). The letter allegedly identified the '678 patent, warned that Defendant's "lamps incorporating white LED filament packages" were "highly likely" to infringe, and put Defendant on notice (Compl. ¶¶ 26-27). The complaint alleges that any infringement after receipt of this letter was and is willful, deliberate, and egregious (Compl. ¶¶ 28-31).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of physical structure: Does forensic analysis of the accused SYLVANIA filaments reveal a distinct "light diffusing layer" that is structurally separate from the "wavelength conversion layer", as depicted in the patent's preferred embodiments, or is the filament a single, composite material where scattering and photoluminescent particles are intermixed?
- A key evidentiary question will be one of functional proof: Beyond relying on Defendant's marketing slogan "Looks Great Off or On," what objective, technical evidence will Plaintiff present to prove that the accused filament's design "improves an off-state white appearance" in a manner that satisfies the claim limitation, and how will that "improvement" be quantified and benchmarked?
- The case may also turn on a question of claim construction: How will the court define the functional limitation "improves an off-state white appearance"? The outcome will likely depend on whether this is construed as requiring a specific, objective colorimetric standard or a more qualitative, perception-based improvement over the prior art's "yellowish" off-state color.