DCT

3:25-cv-02886

Prosperina Ventures LLC v. Keystone Tech LLC

Log In

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:25-cv-02886, N.D. Tex., 10/23/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Northern District of Texas because Defendant has committed acts of patent infringement in the district and maintains one or more regular and established places of business, including a warehouse located in Dallas, Texas.
  • Core Dispute: Plaintiff alleges that Defendant’s commercial LED light bulb products infringe six U.S. patents related to the design, thermal management, and optical characteristics of LED lamps.
  • Technical Context: The technology at issue concerns improvements in LED lighting, a field that has seen significant market growth as it replaces less efficient incandescent, fluorescent, and HID lighting technologies.
  • Key Procedural History: The complaint does not reference any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the patents-in-suit.

Case Timeline

Date Event
2010-03-03 Priority Date for U.S. Patent No. 9,310,030
2010-06-08 Priority Date for U.S. Patent No. 10,107,487
2011-04-25 Priority Date for U.S. Patent No. 9,470,882
2013-03-14 Priority Date for U.S. Patent No. 9,651,239
2013-06-28 Priority Date for U.S. Patent No. 9,222,659
2014-04-16 Priority Date for U.S. Patent No. 9,435,528
2015-12-29 U.S. Patent No. 9,222,659 Issued
2016-04-12 U.S. Patent No. 9,310,030 Issued
2016-09-06 U.S. Patent No. 9,435,528 Issued
2016-10-18 U.S. Patent No. 9,470,882 Issued
2017-05-16 U.S. Patent No. 9,651,239 Issued
2018-10-23 U.S. Patent No. 10,107,487 Issued
2025-10-23 Complaint Filed

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

U.S. Patent No. 9,222,659 - LED lamp

  • Issued: December 29, 2015

The Invention Explained

  • Problem Addressed: The patent addresses the challenge of retrofitting existing fluorescent light fixtures with more energy-efficient LED lamps. Traditional fluorescent fixtures use "tombstone connectors," and replacing the entire fixture can be costly and complex (’659 Patent, col. 5:18-29).
  • The Patented Solution: The invention is an LED lamp designed for direct installation into fluorescent fixtures. It features end caps with pairs of pins mounted on a "control member" that can rotate relative to the lamp's main body ('659 Patent, col. 10:44-50; Fig. 7). This allows a user to insert the pins into the linear slot of a tombstone connector and then rotate them to engage the electrical contacts, securing the lamp without needing to rewire the fixture ('659 Patent, col. 12:10-24).
  • Technical Importance: This approach simplifies the market transition from fluorescent to LED technology by enabling a "plug-and-play" replacement, thereby lowering the barrier to adoption for consumers and businesses ('659 Patent, col. 5:23-29).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶34).
  • The essential elements of Claim 1 are:
    • An enclosure that is at least partially optically transmissive.
    • At least one LED inside the enclosure, operable through an electrical path.
    • A first pair of pins mounted in a control member, where the control member is "freely rotatable" relative to the enclosure and is part of the electrical path.
  • The complaint reserves the right to assert additional claims (Compl. ¶35).

U.S. Patent No. 9,310,030 - Non-uniform diffuser to scatter light into uniform emission pattern

  • Issued: April 12, 2016

The Invention Explained

  • Problem Addressed: LED light sources typically produce a forward-directed, Lambertian emission pattern, which differs from the omnidirectional light distribution of traditional incandescent bulbs. This directional lighting can be aesthetically undesirable in general illumination applications (’030 Patent, col. 3:40-56).
  • The Patented Solution: The patent discloses a lamp that uses a specially designed diffuser to reshape the light pattern. The diffuser has "varying scattering properties" across its surface, meaning it scatters light differently in different areas ('030 Patent, Abstract). By intentionally creating non-uniformity—such as varying the thickness of a scattering film or the density of scattering particles—the diffuser can redirect the forward-focused LED light into a more uniform, omnidirectional pattern that better mimics an incandescent bulb ('030 Patent, col. 8:1-13; col. 21:1-14).
  • Technical Importance: This technology allows LED replacement bulbs to more closely replicate the familiar and often preferred light distribution of incandescent lamps, increasing their consumer acceptance and functional utility ('030 Patent, col. 4:5-13).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶39).
  • The essential elements of Claim 1 are:
    • A solid-state light source emitting a substantially forward emission pattern.
    • A diffuser that alters the forward emission pattern to create one of greater uniformity.
    • The diffuser comprises a plurality of attributes used to control the emission profile.
    • The diffuser comprises "varying scattering properties over its surface" based on the desired profile.
  • The complaint reserves the right to assert additional claims (Compl. ¶40).

U.S. Patent No. 9,435,528 - LED lamp with LED assembly retention member

  • Patent Identification: 9,435,528, LED lamp with LED assembly retention member, Issued September 6, 2016.
  • Technology Synopsis: This patent addresses the mechanical stress caused by different rates of thermal expansion between an LED assembly and its heat sink. The invention provides a "retention member" that is mounted on the heat sink to restrain the LED assembly from moving in an axial direction, ensuring the integrity of the thermal and electrical connections during thermal cycling (’528 Patent, Abstract; col. 17:25-41).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶44).
  • Accused Features: The complaint accuses the Keystone A23 HID Bulb and substantially similar products of infringement (Compl. ¶44).

U.S. Patent No. 9,470,882 - Optical arrangement for a solid-state lamp

  • Patent Identification: 9,470,882, Optical arrangement for a solid-state lamp, Issued October 18, 2016.
  • Technology Synopsis: The patent describes an optical system to improve light-output efficiency. It pairs a primary Total Internal Reflection (TIR) optical element with a "highly reflective secondary reflector" that is physically separate from, but adjacent to, the primary optic. This secondary reflector captures and redirects stray light that escapes the TIR element, preventing its loss and increasing the lamp's overall lumen output (’882 Patent, Abstract; col. 1:40-55).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶49).
  • Accused Features: Various Keystone PAR and MR series bulbs are accused of infringement (Compl. ¶49).

U.S. Patent No. 9,651,239 - LED lamp and heat sink

  • Patent Identification: 9,651,239, LED lamp and heat sink, Issued May 16, 2017.
  • Technology Synopsis: This patent discloses a heat sink design intended to maximize surface area for thermal dissipation without substantially altering a standard lamp form factor. The design features fins that include "overhangs" extending over portions of the lamp's enclosure and base, which increases the available heat-dissipating surface area exposed to the ambient environment (’239 Patent, Abstract).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶54).
  • Accused Features: The Keystone LED33PSPAR38 Bulb and Keystone A23 HID Bulb are accused of infringement (Compl. ¶54).

U.S. Patent No. 10,107,487 - LED light bulbs

  • Patent Identification: 10,107,487, LED light bulbs, Issued October 23, 2018.
  • Technology Synopsis: The invention relates to an LED light engine fabricated from a substantially planar substrate that is subsequently shaped or bent to form a "substantially rigid upright support structure." This allows LEDs to be mounted on multiple non-coplanar surfaces, enabling the creation of an omnidirectional light emission pattern from a compact and manufacturable design (’487 Patent, col. 10:46-61; Claim 11).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶59).
  • Accused Features: A wide range of Keystone products, including MR16, G24, A23 HID, PAR, and other LED bulbs, are accused of infringement (Compl. ¶59, ¶11).

III. The Accused Instrumentality

Product Identification

The complaint identifies a broad range of Defendant's commercial LED lighting products as the "Accused Products" (Compl. ¶2). Specific examples cited include the "Keystone 9.5W CCT Selectable 4-Pin CFL Replacement Bulb," "Keystone PAR38 18W 5000K 2031 Lumens Bulb," and "Keystone A23 HID Bulb" (Compl. ¶2, ¶34, ¶39, ¶44).

Functionality and Market Context

The Accused Products are solid-state lamps designed as replacements for legacy lighting technologies such as compact fluorescent (CFL), high-intensity discharge (HID), and incandescent bulbs (Compl. ¶34, ¶39, ¶44). The complaint alleges these products are "marketed, offered, and distributed throughout the United States" (Compl. ¶2). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references exemplary claim charts in Exhibits 7-12 but does not attach them (Compl. ¶35, ¶40). The analysis below summarizes the narrative infringement theories presented for the two lead patents.

’659 Patent Infringement Allegations

The complaint alleges that the "Keystone 9.5W CCT Selectable 4-Pin CFL Replacement Bulb," designed to replace fluorescent tubes, infringes at least Claim 1 of the ’659 Patent (Compl. ¶34). The infringement theory suggests that the accused bulb incorporates an enclosure with LEDs and features end caps with pins mounted on a rotatable member to allow for installation into existing tombstone-style fixtures, thereby mapping onto the elements of Claim 1 (Compl. ¶34, ¶35).

  • Identified Points of Contention:
    • Scope Questions: A central question may be the construction of the term "freely rotatable." The dispute could focus on whether the accused product's pin mechanism, which may have mechanical stops (e.g., at 90 degrees), falls within the scope of "freely rotatable" as understood in the patent.
    • Technical Questions: The factual evidence will concern the specific mechanical design of the accused bulb's end caps. Analysis will likely examine whether the pin-containing component is a distinct "control member" and whether its rotation relative to the lamp's enclosure matches the claim's requirements.

’030 Patent Infringement Allegations

The complaint alleges that various directional bulbs, such as the "Keystone PAR38 18W 5000K 2031 Lumens Bulb," infringe at least Claim 1 of the ’030 Patent (Compl. ¶39). The theory is that these products use a diffuser to modify the directional light from an LED source into a more uniform pattern suitable for general illumination. The complaint implies this is achieved through a diffuser with "varying scattering properties over its surface" as required by the claim (Compl. ¶39, ¶40).

  • Identified Points of Contention:
    • Scope Questions: The interpretation of "varying scattering properties" will be critical. The question may arise whether minor, unintentional variations from the manufacturing process meet this limitation, or if the term requires intentionally engineered, significant non-uniformity as described in the patent's embodiments.
    • Technical Questions: An evidentiary question will be whether the accused products' diffusers are functionally uniform or if they possess measurably different scattering characteristics across their surfaces. Answering this may require optical testing and analysis of the diffuser's material composition and structure.

V. Key Claim Terms for Construction

The Term: "freely rotatable" ('659 Patent, Claim 1)

  • Context and Importance: This term is central to the infringement analysis for the '659 patent. Its definition will determine whether replacement bulbs with common 90-degree rotational locks for installation meet the claim limitation. Practitioners may focus on this term because Defendant could argue that a mechanism with mechanical stops is not "freely" rotatable.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes rotating the control member 90 degrees to engage electrical contacts in a tombstone fixture ('659 Patent, col. 12:18-24). This context suggests "freely rotatable" may be construed to mean "capable of the rotation necessary for installation," rather than requiring unlimited 360-degree movement.
    • Evidence for a Narrower Interpretation: The plain meaning of "freely" could imply an absence of any restriction on movement. The patent does not appear to explicitly define the term or discuss mechanical stops, which may support an argument that the inventors intended a more literal, unrestricted meaning.

The Term: "varying scattering properties over its surface" ('030 Patent, Claim 1)

  • Context and Importance: This phrase captures the core technical contribution of the '030 patent. The infringement case hinges on whether the accused products' diffusers embody this feature. Practitioners may focus on this term because it presents a clear factual dispute: either the diffusers are uniform, or they are intentionally non-uniform in the manner claimed.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification discloses multiple ways to achieve this property, including varying the thickness of a scattering film, altering the density of scattering particles, or changing surface roughness ('030 Patent, col. 8:1-13; col. 21:1-14). This could support a construction that covers any intentional, functional non-uniformity.
    • Evidence for a Narrower Interpretation: The patent's figures and description emphasize deliberate and significant variations designed to achieve a specific optical outcome (e.g., ’030 Patent, Fig. 89). This could support a narrower construction that excludes incidental or minor manufacturing variations that do not serve the claimed function of reshaping the emission pattern.

VI. Other Allegations

  • Indirect Infringement: The complaint includes a general allegation of "indirectly" infringing for each asserted patent but does not plead specific facts to support the required elements of knowledge and intent for induced infringement, or to establish the elements of contributory infringement (Compl. ¶34, ¶39, ¶44, ¶49, ¶54, ¶59).

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

  1. A central issue will be one of evidentiary proof: For the patents concerning optical properties (e.g., '030 and '882), can Plaintiff demonstrate through technical analysis that the accused Keystone bulbs actually incorporate the claimed features, such as diffusers with "varying scattering properties" or a secondary reflector system that captures stray light?
  2. A key legal question will be one of claim construction: Can the term "freely rotatable" in the '659 patent be construed to cover standard industry designs for CFL-replacement bulbs that rotate and lock into place, or does its plain meaning require a more unrestricted movement that these products may not possess?
  3. A further issue will be one of technical design: For the patents related to mechanical and thermal structures (e.g., '528, '239, '487), does the internal construction of the accused Keystone bulbs—regarding their heat sinks, LED assembly retention, and circuit board formation—map onto the specific structural limitations recited in the asserted claims?