DCT

1:20-cv-00052

Bench Walk Lighting LLC v. Lite On Technology Corp

Log In
Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:20-cv-00052, D. Del., 01/14/2020
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendants are foreign entities or are incorporated in Delaware, have transacted business in the district, and have committed or induced acts of patent infringement within the district.
  • Core Dispute: Plaintiff alleges that Defendant’s light-emitting diode (LED) products infringe eleven U.S. patents related to LED manufacturing methods, device structures, and packaging technologies.
  • Technical Context: The patents cover fundamental aspects of modern LED manufacturing, including methods for applying phosphor coatings, structural designs for improving optical performance and heat dissipation, and packaging for surface-mount applications.
  • Key Procedural History: Plaintiff alleges sending a notice letter to Defendants on May 25, 2019, asserting infringement of the patents-in-suit. For U.S. Patent 8,405,181, the complaint alleges that Defendant had knowledge of the patent due to its citation during the prosecution of Defendant's own Chinese patent application, a fact that may be relevant to the willfulness analysis. The patents asserted in this case were originally assigned to Agilent Technologies, Inc. or Avago Technologies Limited.

Case Timeline

Date Event
2003-03-07 U.S. Patent 6,806,658 Priority Date
2004-04-02 U.S. Patent 7,488,990 Priority Date
2004-10-19 U.S. Patent 6,806,658 Issued
2005-03-07 U.S. Patent 7,115,428 Priority Date
2005-08-19 U.S. Patent 7,519,287 Priority Date
2006-10-03 U.S. Patent 7,115,428 Issued
2007-03-09 U.S. Patent 7,470,936 Priority Date
2008-01-28 U.S. Patent 7,847,300 Priority Date
2008-12-30 U.S. Patent 7,470,936 Issued
2009-01-23 U.S. Patent 8,034,644 Priority Date
2009-02-10 U.S. Patent 7,488,990 Issued
2009-04-14 U.S. Patent 7,519,287 Issued
2009-07-28 U.S. Patent 9,887,338 Priority Date
2010-12-07 U.S. Patent 7,847,300 Issued
2011-02-23 U.S. Patent 9,209,373 Priority Date
2011-03-14 U.S. Patent 9,882,094 Priority Date
2011-03-16 U.S. Patent 8,405,181 Priority Date
2011-10-11 U.S. Patent 8,034,644 Issued
2013-03-26 U.S. Patent 8,405,181 Issued
2015-12-08 U.S. Patent 9,209,373 Issued
2018-01-30 U.S. Patent 9,882,094 Issued
2018-02-06 U.S. Patent 9,887,338 Issued
2019-05-25 Plaintiff’s notice letter sent to Defendants
2020-01-14 Complaint Filed

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

U.S. Patent No. 6,806,658 - METHOD FOR MAKING AN LED

The Invention Explained

  • Problem Addressed: The patent's background describes prior art manufacturing methods for white LEDs that had "a poor yield due to uneven phosphor dispersion in the reflecting cup" and where the "liquid casting epoxy tends to shrink during the heat curing process" (Compl. ¶18; ’658 Patent, col. 1:31-41). These issues led to inconsistent color output.
  • The Patented Solution: The invention proposes a method using "a UV cured epoxy that sets in a very short period of time together with a thixotropic agent that retards the sedimentation of the phosphor particles" (Compl. ¶19; ’658 Patent, col. 2:2-4). By curing the epoxy mixture with UV light in a matter of seconds, the phosphor particles are locked in place before they can settle, ensuring a uniform layer and consistent color conversion (’658 Patent, col. 2:54-57).
  • Technical Importance: This method provided a way to increase manufacturing yield and color consistency for phosphor-converted LEDs, a critical step in making them a viable mass-market light source.

Key Claims at a Glance

  • The complaint asserts independent claim 3 (Compl. ¶22).
  • Claim 3 recites a method for fabricating an LED with the following essential elements:
    • mounting an LED that emits light of a first wavelength on a substrate;
    • suspending a powder of a phosphor that converts light of the first wavelength to light of a second wavelength in a photo-curable material;
    • covering the LED with a layer of the photo-curable medium; and
    • exposing the photo-curable medium to light of a curing wavelength,
    • wherein the photo-curable medium sets in a time less than that required for a change in concentration of the phosphor in the phosphor layer over the LED of more than 0.5 percent.
  • The complaint also asserts dependent claim 4 and reserves the right to assert additional claims (Compl. ¶22).

U.S. Patent No. 7,115,428 - METHOD FOR FABRICATING LIGHT-EMITTING DEVICES UTILIZING A PHOTO-CURABLE EPOXY

The Invention Explained

  • Problem Addressed: The patent addresses several prior art problems, including poor yield from uneven phosphor dispersion, the tendency for the "viscous epoxy-phosphor layer [to] slump" between application and oven curing, and the large volume of expensive epoxy-phosphor mixture required to fill the device packaging (Compl. ¶¶40-42; ’428 Patent, col. 2:44-48, col. 2:60-62).
  • The Patented Solution: The invention describes a method where a mixture of photocurable epoxy and phosphor is dispensed onto the face of an LED die and then irradiated with light to cure it "in a time period that is less than the time period in which the phosphor particles settle" (Compl. ¶43; ’428 Patent, col. 1:52-57). This rapid curing prevents both slumping and settling. The patent also describes using a reflective cup or other structure as a mold to control the epoxy layer's thickness, reducing material waste (’428 Patent, col. 2:49-50).
  • Technical Importance: This method aimed to improve manufacturing efficiency by reducing cure times, minimizing material waste, and increasing color uniformity in phosphor-converted LEDs.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶48).
  • Claim 1 recites a method for fabricating a light emitting device with the following essential elements:
    • mounting a die comprising a semiconductor light emitting device on a carrier, the die having a face through which light is emitted;
    • dispensing a bead of a mixture of photo curable epoxy and phosphor particles on said face in a pattern that covers said face; and
    • irradiating the dispensed mixture in a time period that is less than the time period in which the phosphor particles settle, wherein the time period is less than 1 second.
  • The complaint reserves the right to assert additional claims (Compl. ¶45).

U.S. Patent No. 7,470,936 - LIGHT EMITTING DIODE WITH A STEP SECTION BETWEEN THE BASE AND THE LENS OF THE DIODE

  • Technology Synopsis: The patent addresses the problem of resin material used in LED displays overflowing and contacting the lens during manufacturing, which reduces contrast and narrows the viewing angle (Compl. ¶66). The solution is a physical "step section" disposed between the base and the lens, which acts as a barrier to prevent the resin from directly contacting the lens and controls the height of the resin fill (Compl. ¶68).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶72).
  • Accused Features: The LTPL-C035GH530 product is accused of having a "step section disposed between the base and the lens" (Compl. ¶80).

U.S. Patent No. 7,488,990 - USING MULTIPLE TYPES OF PHOSPHOR IN COMBINATION WITH A LIGHT EMITTING DEVICE

  • Technology Synopsis: The patent addresses the limited range of colors achievable with a single-color phosphor combined with a blue LED (Compl. ¶93). The solution involves using "multiple types of phosphor," such as a mixture of green and yellow phosphors, which allows for the creation of a wider variety of colors by adjusting the mixture ratio (Compl. ¶¶94-95).
  • Asserted Claims: The complaint asserts independent claim 12 (Compl. ¶98).
  • Accused Features: The Lite-On M08 CoB Product Series is accused of using an epoxy that includes a first type of phosphor that emits green light and a second type of phosphor that emits yellow light (Compl. ¶¶103-104).

U.S. Patent No. 7,519,287 - ELECTRONIC FLASH, IMAGING DEVICE AND METHOD FOR PRODUCING A FLASH OF LIGHT HAVING A RECTANGULAR RADIATION PATTERN

  • Technology Synopsis: The patent addresses the inefficiency of conventional LED flashes that produce a round or oval radiation pattern, which does not match the rectangular field of view of a camera's image sensor, resulting in wasted light (Compl. ¶¶117-118). The solution is to use a "diffractive optical element" to shape the light from the LED into a rectangular radiation pattern that more closely matches the sensor (Compl. ¶120).
  • Asserted Claims: The complaint asserts independent claim 16 (Compl. ¶124).
  • Accused Features: The LTPL-C06M5WAGB product is accused of using a diffractive optical element to produce a rectangular radiation pattern (Compl. ¶128).

U.S. Patent No. 7,847,300 - LIGHT-EMITTING DIODE PACKAGE

  • Technology Synopsis: The patent addresses problems in small Surface Mount Device (SMD) LED packages where bending an electrode lead can "leave a clearance between the electrode pad and a portion of the housing" (Compl. ¶142). The solution is an LED package design where a portion of the housing wall is made thicker than other portions, which increases the contact area with the lead electrode and prevents the formation of a clearance (Compl. ¶144).
  • Asserted Claims: The complaint asserts at least one claim of the patent, with infringement allegations mapped to an exemplary product (Compl. ¶148).
  • Accused Features: The LTST-M140KFKT product is accused of having a housing with a bottom surface comprising a first bottom surface and a "second bottom surface having a first recessed space" where the electrode lead is arranged (Compl. ¶¶155-156).

U.S. Patent No. 8,034,644 - LIGHT EMITTING DEVICE

  • Technology Synopsis: The patent addresses the trade-off between the superior optical performance of through-the-wave (TTW) LEDs and the manufacturing benefits of surface-mount technology (SMT) LEDs (Compl. ¶170). The invention provides a solution by teaching an "SMT device that has TTW light characteristics," combining the advantages of both technologies (Compl. ¶173).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶177).
  • Accused Features: The LTW5H3DVBJ-DK-002A is accused of being made by the claimed method, which involves fabricating lines of first and second leads, connecting them with a rail, and encapsulating them into a single unit (Compl. ¶¶179-185).

U.S. Patent No. 8,405,181 - HIGH BRIGHTNESS AND HIGH CONTRAST PLASTIC LEADED CHIP CARRIER LED

  • Technology Synopsis: The patent addresses the problem that prior art Plastic Leaded Chip Carrier (PLCC) packages could not "simultaneously provide high contrast and high brightness" (Compl. ¶199). The solution is a design where the lead frame is incorporated "into the interior walls of the reflector cup," which enhances reflectivity without an additional manufacturing step (Compl. ¶201).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶205).
  • Accused Features: The LTST-G683ESBW product is accused of having a reflector cup where the wall extending from the bottom surface "comprises a portion of the lead frame and a portion of the plastic housing" (Compl. ¶210).

U.S. Patent No. 9,209,373 - HIGH POWER PLASTIC LEADED CHIP CARRIER WITH INTEGRATED METAL REFLECTOR CUP AND DIRECT HEAT SINK

  • Technology Synopsis: The patent addresses the complexity and cost of manufacturing high-power LED packages with sufficient heat dissipation, particularly those that use a separate heat sink slug (Compl. ¶225). The solution is a lead frame that integrates the heat sink and reflector cup, which can be created in a single manufacturing step like stamping, simplifying the process (Compl. ¶227).
  • Asserted Claims: The complaint asserts independent claim 13 (Compl. ¶231).
  • Accused Features: The LTW-5630AZL27-EUH product is accused of having a heat sink that is separated from the second metal lead and disposed between the first and second metal leads (Compl. ¶237).

U.S. Patent No. 9,882,094 - LIGHT SOURCE WITH INNER AND OUTER BODIES COMPRISING THREE DIFFERENT ENCAPSULANTS

  • Technology Synopsis: The patent addresses reliability and contrast issues for small LEDs used in outdoor displays, which must be bright yet have low reflectivity to maintain contrast (Compl. ¶¶251-254). The solution is a "light-emitting device having an inner reflective body and an outer non-reflective body," where the outer body reduces reflection of ambient light, and interlock structures improve reliability (Compl. ¶¶255, 257).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶261).
  • Accused Features: The LTPA-S38FUMWE product is accused of having a first encapsulant defining an inner reflective body and a second encapsulant defining an outer non-reflective body (Compl. ¶¶265, 268).

U.S. Patent No. 9,887,338 - LIGHT EMITTING DIODE DEVICE

  • Technology Synopsis: The patent addresses the problem of "multiple thermal interfaces, comprising multiple layers of dissimilar materials, which impede heat flow" and add manufacturing cost in LED packages (Compl. ¶¶282-283). The solution is a design where the LED is mounted on a substrate with a solder-filled via that "acts as a heat plug," creating a direct thermal path to a heat sink and reducing the number of thermal interfaces (Compl. ¶286).
  • Asserted Claims: The complaint asserts independent claim 3 (Compl. ¶293).
  • Accused Features: The LTPL-C034UVH430 is accused of being made by the claimed method, which includes forming a solderable metallic surface on the LED, forming an opening in a printed circuit board, and mounting the metallic surface across the opening to connect to a heat sink (Compl. ¶¶295-299).

III. The Accused Instrumentality

Product Identification

The complaint identifies multiple series of Lite-On LED products, with specific product lines accused of infringing specific patents. The lead exemplary products include the LTPL-M09830ZS30-T0 M09 Series, LTPL-C035GH530, Lite-On M08 CoB Product Series, LTPL-C06M5WAGB, LTST-M140KFKT, LTW5H3DVBJ-DK-002A, LTST-G683ESBW, LTW-5630AZL27-EUH, LTPA-S38FUMWE, and LTPL-C034 series (Compl. ¶¶20, 45, 71, 96, 121, 145, 174, 202, 228, 258, 290).

Functionality and Market Context

  • The accused products are various types of light-emitting diodes (LEDs) used for general lighting, displays, and electronic components (Compl. ¶5). The complaint alleges these products are manufactured, used, sold, and imported by the Defendants (Compl. ¶2).
  • The infringement allegations focus on the specific manufacturing methods and physical structures of these LEDs. For example, the complaint alleges the M09 Series LEDs are manufactured using a photo-curable epoxy that sets rapidly to prevent phosphor from settling (Compl. ¶¶26-27, 51). Another product, the LTPL-C035GH530, is alleged to incorporate a specific "step section" in its physical package to control resin flow (Compl. ¶80). The LTPL-C06M5WAGB is alleged to incorporate a diffractive optical element to produce a rectangular light pattern suitable for camera flashes (Compl. ¶128). An annotated image of this product's datasheet is provided, showing a "Rectangular radiation pattern with aspect ratio of (16:9)" (Compl. p. 28).

IV. Analysis of Infringement Allegations

'658 Patent Infringement Allegations

Claim Element (from Independent Claim 3) Alleged Infringing Functionality Complaint Citation Patent Citation
mounting a LED that emits light of a first wavelength on a substrate; The accused LTPL-M09830ZS30-T0 M09 Series LED is fabricated by mounting an LED die on a substrate. ¶23 col. 1:10-12
suspending a powder of a phosphor that converts light of said first wavelength to light of a second wavelength in a photo-curable material that sets upon exposure to light of a curing wavelength; The accused product comprises a powdered phosphor suspended in a photo-curable medium that sets upon exposure to light. The complaint includes an image of the accused product with the phosphor powder circled in red (Compl. p. 6). ¶¶24-26 col. 1:19-21
covering said LED with a layer of said photo-curable medium; and The phosphor and photo-curable medium form a layer over the LED die. ¶27 col. 1:21-23
exposing said photo-curable medium to light of said curing wavelength, The complaint alleges that photo (UV) curing is a dominant technique for encapsulant curing used in manufacturing the accused product. ¶26 col. 2:37-39
wherein said photo-curable medium sets in a time less than that required for a change in concentration of said phosphor in said phosphor layer over said LED of more than 0.5 percent. The complaint alleges the photo-curable medium in the accused product sets in a time less than required for this specified change in phosphor concentration, citing the general benefits of expedient photo-curing. ¶27 col. 3:24-27
  • Identified Points of Contention:
    • Functional/Evidentiary Question: The final limitation of claim 3 is functional and quantitative: setting in a time "less than that required for a change in concentration... of more than 0.5 percent." The complaint supports this with citations to general technical articles about the benefits of UV curing (Compl. ¶27). A key point of contention will be whether the complaint provides sufficient factual support for this specific, quantified functional result as it pertains to Defendant's actual manufacturing process, and what evidence will be required to prove it.

'428 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
mounting a die comprising a semiconductor light emitting device on a carrier, said die having a face through which light is emitted; The accused LTPL-M09830ZS30-T0 M09 Series LED is manufactured by mounting a semiconductor light emitting die on a carrier. The complaint provides an image of the accused "M09 Series" product (Compl. p. 12). ¶49 col. 5:48-50
dispensing a bead of a mixture of photo curable epoxy and phosphor particles on said face in a pattern that covers said face; The manufacturing method for the accused product is alleged to involve dispensing a mixture of photo-curable epoxy and phosphor particles onto the face of the die. ¶50 col. 3:15-17
and irradiating said dispensed mixture in a time period that is less than the time period in which said phosphor particles settle The complaint alleges that curing the phosphor mixture via irradiation is a dominant technique used to minimize the time period in which phosphor particles settle. ¶51 col. 1:55-57
wherein said time period is less than 1 second. The complaint alleges that the irradiation time period is less than 1 second. ¶51 col. 3:32-34
  • Identified Points of Contention:
    • Scope Questions: The interpretation of "the time period in which said phosphor particles settle" will be critical. The parties may dispute how this baseline "settling time" is defined and measured, which is necessary to determine if the accused curing time is "less than" that period.
    • Technical Questions: The complaint alleges the curing time is "less than 1 second" (Compl. ¶51). The case may turn on factual evidence, such as manufacturing process data or expert testing, to determine the actual time period of irradiation used by Defendant and whether it meets this claimed limitation.

V. Key Claim Terms for Construction

Patent: '658 Patent

  • The Term: "a time less than that required for a change in concentration of said phosphor in said phosphor layer over said LED of more than 0.5 percent"
  • Context and Importance: This term from claim 3 defines the required speed of the curing process not by an absolute time, but by a functional outcome related to phosphor stability. The entire infringement analysis for this claim hinges on whether the accused process meets this highly specific, quantified functional threshold. Practitioners may focus on this term because its construction will determine the type of evidence (e.g., process timing, material analysis, simulation) needed to prove or disprove infringement.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification discusses the general problem of phosphor particles settling and the invention's use of a "very fast setting epoxy" to "substantially" reduce this problem (e.g., ’658 Patent, col. 2:54-62). This context may support an interpretation focused on the general goal of preventing meaningful settling, rather than a rigid adherence to a specific test protocol for the 0.5% value.
    • Evidence for a Narrower Interpretation: The claim language itself provides a precise quantitative boundary (0.5%). This may support a narrower construction requiring a specific, measurable, and repeatable change in concentration, potentially limiting the claim's scope to processes that can be proven to stay within this exact numerical limit. The patent does not, however, specify a method for measuring this change.

Patent: '428 Patent

  • The Term: "settle"
  • Context and Importance: This term from claim 1 is central to the temporal limitation requiring irradiation "in a time period that is less than the time period in which said phosphor particles settle." The definition of "settle" is critical because it establishes the benchmark against which the accused process's "less than 1 second" curing time is compared.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the problem as phosphor particles "tend[ing] to settle under gravity" over the time between dispensing and curing in an oven (’428 Patent, col. 2:37-43). This could support a broad interpretation where "settle" means any gravity-induced downward movement of particles within the epoxy.
    • Evidence for a Narrower Interpretation: The patent discusses the negative effect of settling as reducing the "amount of phosphor over the chip," which "lowers the ratio of yellow to blue light" (’428 Patent, col. 1:40-44). This could support a narrower construction where "settle" requires a degree of particle movement sufficient to cause a measurable or significant change in the resulting light color, not just any particle movement.

VI. Other Allegations

  • Indirect Infringement: For each asserted patent, the complaint alleges both induced and contributory infringement. The allegations state that Defendants knowingly encourage infringement by providing "data sheets, technical guides, demonstrations... installation guides, and other forms of support" (e.g., Compl. ¶¶33-35, 57-59). It is also alleged that the accused products are not suitable for substantial non-infringing use.
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents, based on alleged pre-suit knowledge from a notice letter dated May 25, 2019 (e.g., Compl. ¶28). For the ’181 Patent, the complaint makes a more specific allegation that Defendants had actual knowledge from their own patent prosecution activities, stating that Defendant's Chinese patent application CN103367344B cites the ’181 Patent (Compl. ¶213).

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

  • A core issue will be one of evidentiary proof for functional claims: For patents like the ’658 and ’428, which claim manufacturing methods defined by functional outcomes (e.g., curing before a 0.5% phosphor concentration change; curing in "less than 1 second"), a key question will be what factual evidence Plaintiff can obtain and present to demonstrate that Defendant's high-volume, internal manufacturing processes meet these specific, time-sensitive limitations.
  • A second key question will be one of structural interpretation: For the numerous patents directed to specific physical structures (e.g., the '936 patent's "step section," the '181 patent's reflector cup wall composed of both plastic and lead frame), the case will likely turn on claim construction and the factual question of whether the precise geometries and material compositions of the accused LED packages read on the claimed elements.
  • A final dispositive issue for damages will be willfulness and the scope of pre-suit knowledge: The case presents a significant question regarding willfulness, particularly for the ’181 patent. The court will have to consider whether Defendant's citation of the ’181 patent during its own prosecution establishes pre-suit knowledge of that patent and a corresponding duty to avoid infringement, potentially exposing Defendant to enhanced damages.