1:19-cv-21507
Seoul Semiconductor Co Ltd v. Satco Products Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Seoul Semiconductor Co., Ltd. (Republic of Korea); Seoul Viosys Co., Ltd. (Republic of Korea)
- Defendant: Satco Products, Inc. (New York)
- Plaintiff’s Counsel: The Brickell IP Group; Holland & Knight LLP
- Case Identification: 1:19-cv-21507, S.D. Fla., 04/19/2019
- Venue Allegations: Plaintiff alleges venue is proper because Defendant has committed acts of infringement in the district and maintains a regular and established place of business in Miami Gardens, Florida.
- Core Dispute: Plaintiff alleges that Defendant’s light-emitting diode (LED) lamps and modules infringe eleven patents related to various aspects of LED technology, including AC power operation, device structure, packaging, and driver circuitry.
- Technical Context: The technology at issue involves light-emitting diodes (LEDs), which are highly efficient semiconductor devices that have become a dominant technology in the global lighting market.
- Key Procedural History: The complaint does not mention any prior litigation or post-grant proceedings. However, the provided patent documents indicate that multiple asserted patents have been subject to subsequent Inter Partes Review (IPR) proceedings. Notably, the exemplary claims asserted in the complaint for U.S. Patent Nos. 9,343,631 (Claim 1), 8,860,331 (Claim 11), and 7,081,722 (Claim 15) were later cancelled in IPRs decided after the complaint's filing date. This development may significantly impact the viability of the infringement counts associated with those claims.
Case Timeline
| Date | Event |
|---|---|
| 2005-02-04 | Priority Date: U.S. Patent No. 7,081,722 |
| 2005-06-22 | Priority Date: U.S. Patent No. 9,627,435 |
| 2005-06-28 | Priority Date: U.S. Patent Nos. 8,716,946 & 8,860,331 |
| 2006-07-25 | Issue Date: U.S. Patent No. 7,081,722 |
| 2008-11-18 | Priority Date: U.S. Patent No. 10,134,967 |
| 2009-03-06 | Priority Date: U.S. Patent No. 7,667,225 |
| 2009-03-18 | Priority Date: U.S. Patent No. 8,513,899 |
| 2009-11-13 | Priority Date: U.S. Patent No. 9,343,631 |
| 2010-01-05 | Priority Date: U.S. Patent No. 9,716,210 |
| 2010-02-23 | Issue Date: U.S. Patent No. 7,667,225 |
| 2013-08-20 | Issue Date: U.S. Patent No. 8,513,899 |
| 2014-05-06 | Issue Date: U.S. Patent No. 8,716,946 |
| 2014-06-12 | Priority Date: U.S. Patent No. 9,807,828 |
| 2014-10-14 | Issue Date: U.S. Patent No. 8,860,331 |
| 2014-04-22 | Priority Date: U.S. Patent No. 9,978,919 |
| 2016-05-17 | Issue Date: U.S. Patent No. 9,343,631 |
| 2017-04-18 | Issue Date: U.S. Patent No. 9,627,435 |
| 2017-07-25 | Issue Date: U.S. Patent No. 9,716,210 |
| 2017-10-31 | Issue Date: U.S. Patent No. 9,807,828 |
| 2018-05-22 | Issue Date: U.S. Patent No. 9,978,919 |
| 2018-11-20 | Issue Date: U.S. Patent No. 10,134,967 |
| 2019-04-19 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,716,946 - "Light Emitting Device for AC Power Operation," Issued May 6, 2014
The Invention Explained
- Problem Addressed: The patent addresses the "flicker effect" in LEDs driven directly by an alternating current (AC) power source. Because LEDs only activate above a certain threshold voltage, they turn on and off during each AC cycle, resulting in non-continuous light emission that can cause eye fatigue. (’946 Patent, col. 2:6-21, 53-60)
- The Patented Solution: The invention proposes an LED device that prolongs the light emission time during an AC cycle. One described method involves using arrays of light-emitting cells where different arrays have different turn-on voltages, allowing some cells to be active even during lower-voltage portions of the cycle. Another solution involves using a "delay phosphor" that continues to emit light after the LED chip itself has turned off. (’946 Patent, Abstract; col. 5:35-43) This results in a luminous intensity that remains above zero throughout the AC cycle.
- Technical Importance: This technology enables simpler and more direct operation of LEDs from standard AC wall outlets, potentially reducing the need for complex AC-to-DC conversion circuitry in lighting products. (’946 Patent, col. 2:42-53)
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶26).
- Essential elements of claim 1 include:
- A light emitting cell array with series-connected light emitting cells configured to receive a periodically changing input voltage.
- The device emits light with a periodically changing luminous intensity that has a minimum value greater than zero even when the input voltage falls to a level ("first voltage value") that does not turn on the cells.
- Each light emitting cell comprises an inclined side surface.
U.S. Patent No. 9,343,631 - "Light Emitting Diode Chip Having Distributed Bragg Reflector and Method of Fabricating the Same," Issued May 17, 2016
The Invention Explained
- Problem Addressed: Distributed Bragg Reflectors (DBRs) are used on the back of LED substrates to reflect light forward and increase efficiency. However, a standard DBR is typically optimized for a narrow wavelength band (e.g., the blue light emitted by the LED die) and has poor reflectivity for other colors, such as the longer-wavelength light created when phosphors convert the blue light to create white light. (’631 Patent, col. 1:44-53)
- The Patented Solution: The invention describes a dual-DBR structure. A first DBR, closer to the substrate, is designed to have higher reflectivity for the longer wavelength light (converted by the phosphor). A second DBR, positioned behind the first one, is designed to have higher reflectivity for the shorter wavelength light (emitted by the LED). (’631 Patent, Abstract; Fig. 4) This layered approach improves reflectivity across the full spectrum of light produced by the device.
- Technical Importance: By improving reflectivity for both the direct and phosphor-converted light, this invention increases the total light extraction efficiency of white LEDs, a key factor for performance in the general lighting market. (’631 Patent, col. 2:8-14)
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶39).
- Essential elements of claim 1 include:
- A light-emitting diode chip with a substrate and a light-emitting structure that emits a first (blue) wavelength range.
- A phosphor that converts light to a second wavelength range.
- A first DBR and a second DBR on the substrate's second surface, with the first DBR closer to the substrate.
- The first DBR has higher reflectivity for the second (longer) wavelength range than the first.
- The second DBR has higher reflectivity for the first (shorter) wavelength range than the second.
U.S. Patent No. 8,860,331 - "Light Emitting Device for AC Power Operation," Issued October 14, 2014
Technology Synopsis
This patent addresses the AC flicker problem by using a transparent member containing at least two types of phosphors with different characteristics. A first phosphor has a relatively long decay time, and a second phosphor has a relatively short decay time, which together help to smooth out the light output across the AC cycle (’331 Patent, Abstract).
Asserted Claims
Independent claim 11 is asserted (Compl. ¶46).
Accused Features
The S9581 lamp is accused of infringing by allegedly incorporating a transparent member with two different phosphor types, one with an elongated shape and long decay time, and another with a circular shape and short decay time (Compl. ¶48-52).
U.S. Patent No. 9,627,435 - "Light Emitting Device," Issued April 18, 2017
Technology Synopsis
This patent describes a specific physical structure for an LED device with multiple light-emitting cells. The invention focuses on features like a continuous inclined surface on the semiconductor layers to improve light extraction, and the arrangement of conductive (e.g., ITO) and insulation layers to create robust electrical connections between cells (’435 Patent, Abstract).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶56).
Accused Features
The S9581 lamp is accused of infringing by allegedly having light-emitting cells with the claimed continuous inclined surface, metallic and transparent (ITO) conductive layers, and multiple light-transmitting insulation layers (SiO2) arranged as claimed (Compl. ¶62-65).
U.S. Patent No. 9,716,210 - "Light Emitting Diode and Method of Fabricating the Same," Issued July 25, 2017
Technology Synopsis
This patent describes a specific semiconductor layer structure for an LED designed to improve performance. The structure includes a superlattice layer and a spacer layer positioned between the active region and the n-type contact layer, with specific bandgap energy relationships between the layers intended to enhance crystal quality and efficiency (’210 Patent, Abstract).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶69).
Accused Features
The S9386 lamp is accused of infringing by allegedly incorporating an epi-structure with the claimed active region, superlattice layer, and spacer layer, where the layers have the claimed relative bandgap properties (Compl. ¶71-72).
U.S. Patent No. 7,667,225 - "Light Emitting Device," Issued February 23, 2010
Technology Synopsis
This patent relates to an LED with a multi-quantum well (MQW) structure where the concentration of indium within the well layers is intentionally varied. This variation creates "carrier trap portions" with a lower band-gap energy, which are designed to trap charge carriers (electrons and holes) and enhance the probability of efficient radiative recombination (’225 Patent, Abstract; col. 2:13-22).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶75).
Accused Features
The S9581 lamp is accused of infringing, with the complaint providing transmission electron microscope images from an S9386 lamp allegedly showing a multi-quantum well structure where the indium concentration varies, creating the claimed carrier trap portions (Compl. ¶76-78).
U.S. Patent No. 9,978,919 - "Light Emitting Device," Issued May 22, 2018
Technology Synopsis
This patent describes the mechanical design of an LED package containing two metal leads. The invention specifies that the leads have both thick and thin portions and that the separation region between them has a different shape at the top and bottom, with the top separation region including bends, creating an asymmetrical structure designed for improved mechanical integrity (’919 Patent, Abstract).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶81).
Accused Features
The S9440 lamp's LED package is accused of infringing by allegedly having two metal leads with the claimed thick and thin portions, asymmetrical halves, and a separation region with two bends (Compl. ¶85-87).
U.S. Patent No. 10,134,967 - "Light Emitting Device," Issued November 20, 2018
Technology Synopsis
This patent describes an LED package structure with lead frames that include three undercut or "inset" sidewalls. These undercuts create a "fixing space" that allows the encapsulating resin or molding to lock into the lead frame, improving the adhesive force and mechanical stability of the package (’967 Patent, Abstract).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶90).
Accused Features
The S9386 lamp's LED package is accused of infringing by having lead frames with undercut sidewalls on three sides. An optical cross-section and an x-ray image are provided to show a feature where the top surface of the lead frame extends further into the inter-lead space than the bottom surface, allegedly creating the claimed fixing space (Compl. ¶94-95).
U.S. Patent No. 7,081,722 - "Light Emitting Diode Multiphase Driver Circuit and Method," Issued July 25, 2006
Technology Synopsis
This patent describes a method and circuit for driving a string of LEDs that is divided into series-connected groups. Each group is coupled to ground through a separate "phase switch." As the input voltage rises, the groups are turned on sequentially, and the phase switch for an upstream group can be turned off to reduce power dissipation (’722 Patent, Abstract).
Asserted Claims
Independent claim 15 is asserted (Compl. ¶98).
Accused Features
The S9782 LED module is accused of infringing by using two SW5907 integrated circuits to control strings of LEDs. Each circuit allegedly controls three groups of LEDs connected in series, with each group's downstream end connected to an output pin that selectively connects to ground via phase switches (Compl. ¶100).
U.S. Patent No. 9,807,828 - "Alternating Current-Driven Light Emitting Element Lighting Apparatus," Issued October 31, 2017
Technology Synopsis
This patent describes an AC-driven LED apparatus that includes a rectification circuit and an LED driving module. The module applies drive current to different groups of LEDs and includes control circuitry that compares a detected input to a reference value, allowing it to block the drive current based on the comparison, which enables dimming functionality (’828 Patent, Abstract).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶103).
Accused Features
The S9782 LED module is accused of infringing by having a rectifying bridge (DB1) and two SW5907 LED driving modules that apply drive current to groups of LEDs. The complaint alleges the module is dimmable and that its control circuitry compares a detected input to a reference value to block the current (Compl. ¶104-106).
U.S. Patent No. 8,513,899 - "Light Emitting Device and Driving Circuit Thereof," Issued August 20, 2013
Technology Synopsis
This patent describes a light-emitting device with a "pass-through-first" (PTF) unit connected in parallel with a first group of LEDs and in series with a second group. The PTF unit is designed to supply a driving signal to the second group of LEDs when the input AC voltage is below the threshold needed to turn on the first group, thereby extending the device's operating time during the AC cycle (’899 Patent, Abstract).
Asserted Claims
Independent claim 14 is asserted (Compl. ¶109).
Accused Features
The S9782 LED module is accused of infringing by allegedly incorporating PTF units. A specific example cited is a pair of parallel resistors (R32, R33) that provide a driving signal to a unit of 4 LEDs when the input voltage is less than the threshold voltage required for the other 21 LEDs in the set (Compl. ¶111).
III. The Accused Instrumentality
Product Identification
- The complaint accuses four products: the Satco S9581 filament LED lamp, the Satco S9386 PAR16 type LED lamp, the Satco S9440 PAR38 type LED lamp, and the Satco S9782 LED module (Compl. ¶8-11).
Functionality and Market Context
- The S9581 is a filament-style lamp designed to emulate traditional incandescent bulbs (Compl. ¶8). It operates directly from a 120V/60Hz AC input and contains internal circuitry that converts the AC input to a "DC-like power" to drive series-connected light emitting cells on its filaments (Compl. ¶33-35). Images show the lamp, its internal circuit board, and scanning electron microscope (SEM) cross-sections of its LED chips (Compl. ¶27, 31).
- The S9386 is a PAR16 reflector lamp (Compl. ¶9). It is alleged to contain a plurality of LED packages, each including an LED chip on a patterned sapphire substrate, a resin encapsulant with phosphor particles, and a distributed Bragg reflector (DBR) on the substrate (Compl. ¶40-43).
- The S9440 is a PAR38 reflector lamp (Compl. ¶10). Its accused functionality relates to the structure of its LED packages, which allegedly contain two metal leads with specific thick, thin, and asymmetrical portions (Compl. ¶82, 85, 87).
- The S9782 is an LED module containing 50 LED packages and associated driver circuitry (Compl. ¶11, 99). It is alleged to use two "SW5907" AC direct control integrated circuits to drive the LEDs in distinct groups and in multiple phases, enabling dimming functionality (Compl. ¶100, 105). An image of the module's circuit board shows the layout of the LEDs and driver components (Compl. ¶99).
IV. Analysis of Infringement Allegations
’946 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a light emitting cell array configured to receive an input voltage and comprising a plurality of light emitting cells connected in series on a substrate | The S9581 lamp includes LED filaments, each containing a light emitting diode chip with a series-connected array of light emitting cells on a substrate. | ¶27, 30 | col. 4:26-30 |
| the plurality of light emitting cells to emit light in response to the input voltage, the input voltage to periodically change during a period and to have a first voltage value, which does not turn on the plurality of light emitting cells, after a first peak value | The S9581 lamp receives a 120V/60Hz AC input. The alternating current drops below the level necessary to drive the cells after the peak voltage. | ¶33-34 | col. 2:6-14 |
| wherein the light emitting device emits light comprising a periodically changing luminous intensity in response to the input voltage, the periodically changing luminous intensity of the light emitting device has a second peak value and a minimum value, the minimum value of the periodically changing luminous intensity is greater than zero when the input voltage has the first voltage value | Circuit board elements convert the AC input to a cyclical DC-like power that causes the cells to emit light with a periodically changing intensity that "remains non-zero throughout the cycle of the input 120V/60Hz alternating current." | ¶35 | col. 2:53-60 |
| and wherein each light emitting cell comprises an inclined side surface. | SEM cross-section images of the light emitting cells allegedly show that each includes an inclined side surface. The complaint provides a composite SEM image showing this feature (Compl. ¶29-30). | ¶30 | col. 5:23-26 |
Identified Points of Contention:
- Scope Questions: A central question may be the construction of "minimum value... is greater than zero." The defense could argue that this requires a specific mechanism disclosed in the patent (e.g., a delay phosphor or multi-array switching), and that the S9581's general power conversion circuitry does not meet this limitation as properly construed.
- Technical Questions: What evidence does the complaint provide that the "DC-like power" generated by the circuit board (Compl. ¶31, 35) is a direct implementation of the patented solution, versus a standard feature of AC-to-DC converters used in many LED lamps? The analysis may depend on the specific topology of the accused circuit.
’631 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a light-emitting diode chip configured to emit light of a first wavelength range and light of a second wavelength range, including: a substrate; a light-emitting structure... configured to emit light of the first wavelength range; | The S9386 lamp includes an LED chip with an epi-structure on a patterned sapphire substrate. The active layer emits light in the shorter blue wavelength range (the first wavelength range). | ¶42 | col. 3:45-52 |
| a phosphor disposed on the light-emitting structure, | A resin member containing phosphor particles covers the LED and converts a portion of the emitted blue light to a longer wavelength (the second wavelength range). | ¶41-42 | col. 3:53-56 |
| first and second distributed Bragg reflectors (DBRs) disposed on a second surface of the substrate... the first DBR is disposed closer to the substrate than the second DBR | A transmission electron microscope image allegedly shows a DBR on the bottom of the substrate comprising two portions: an upper portion closer to the substrate and a lower portion further from it (Compl. ¶43). | ¶43 | col. 4:1-5 |
| the first DBR comprises a higher reflectivity for light of the second wavelength range than for light of the first wavelength range | The upper DBR portion, comprising relatively thick layers of SiO2 and TiO2, allegedly provides higher reflectivity for the longer wavelength light converted by the phosphor. | ¶43 | col. 4:10-14 |
| and the second DBR comprises a higher reflectivity for light of the first wavelength range than for light of the second wavelength range. | The lower DBR portion, comprising relatively thin layers of SiO2 and TiO2, allegedly provides higher reflectivity for the shorter wavelength blue light emitted by the light emitting structure. | ¶43 | col. 4:14-18 |
Identified Points of Contention:
- Scope Questions: Does the observation of thicker and thinner layers in a single DBR structure (Compl. ¶43) necessarily mean it is two distinct DBRs with differing reflectivity characteristics as claimed, or could it be a single DBR with manufacturing variations?
- Technical Questions: What factual evidence supports the assertion that the "upper DBR provides higher reflectivity for the longer wavelength light" and the "lower DBR provides higher reflectivity for the shorter wavelength... light"? The complaint alleges this function based on the observed structure, but the analysis will depend on expert testimony and optical modeling of the accused device.
V. Key Claim Terms for Construction
For the ’946 Patent:
- The Term: "minimum value of the periodically changing luminous intensity is greater than zero"
- Context and Importance: This term is central to the patent's claimed solution to the "flicker effect." The dispute will likely focus on whether the accused product's method of maintaining some light output during low-voltage portions of the AC cycle falls within the claim's scope. Practitioners may focus on this term because it defines the core functional improvement over the prior art.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is functional and does not specify how the non-zero minimum is achieved. The abstract broadly refers to prolonging the "light emission time." (’946 Patent, Abstract)
- Evidence for a Narrower Interpretation: The specification discloses specific embodiments to achieve this result, such as using switching blocks to activate different LED arrays sequentially or using a "delay phosphor" with a long decay time. A defendant may argue the claim should be limited to these disclosed mechanisms. (’946 Patent, col. 7:1-10; col. 9:35-42)
For the ’631 Patent:
- The Term: "first... DBR comprises a higher reflectivity for light of the second wavelength range" and "second DBR comprises a higher reflectivity for light of the first wavelength range"
- Context and Importance: The invention's novelty rests on this differentiated, dual-function DBR structure. The infringement analysis depends entirely on whether the accused product contains a DBR with these two distinct, functionally different portions. Practitioners may focus on this term because it distinguishes the invention from standard, single-wavelength DBRs.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language defines the two DBRs functionally by their relative reflectivity at different wavelengths, without limiting them to specific materials or layer counts.
- Evidence for a Narrower Interpretation: The detailed description explains that the different reflectivities are achieved through different optical thicknesses of the constituent layers (e.g., thicker layers for the first DBR, thinner for the second). This could support an argument that the claim requires intentionally designed, physically distinct sets of layers, not merely incidental variations. (’631 Patent, col. 5:1-7)
VI. Other Allegations
Willful Infringement
- The complaint alleges that Satco's infringement of the ’946, ’331, and ’435 patents was willful (Compl. ¶37, 54, 67; Prayer for Relief ¶B). The basis for this allegation is stated as "upon information and belief, Satco's infringement has occurred with knowledge of the [’###] patent and knowledge that its acts constitute infringement" (Compl. ¶37). The complaint does not plead specific facts supporting pre-suit knowledge.
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of viability: several of the complaint's exemplary asserted claims (for the '631, '331, and '722 patents) were cancelled in IPR proceedings after the suit was filed. A key question is how the plaintiff will proceed with these counts, and whether the invalidation of these lead claims will influence the strategic direction of the entire, multi-patent case.
- A key evidentiary question will be one of technical proof: for patents like the '631 (DBR) and '225 (carrier traps), can the plaintiff's microscopic analyses (e.g., TEM images) definitively prove that the accused products contain these specific, intentionally engineered nanostructures, or will the defense successfully characterize them as standard manufacturing artifacts that do not practice the claimed inventions?
- For the AC-driven LED patents ('946, '899, '722), a core issue will be one of functional scope: do the accused products' general-purpose driver circuits perform the specific functions required by the claims (e.g., maintaining a "greater than zero" luminous intensity or operating as a "PTF unit"), or is there a fundamental mismatch in technical operation that places the accused products outside the scope of the claims as properly construed?