DCT
1:19-cv-00535
AfterGlow LLC v. Bright Path Lighting Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: AfterGlow, LLC (Virginia)
- Defendant: Bright Path Lighting, Inc. (California)
- Plaintiff’s Counsel: Williams Mullen; Wanger Jones Helsley PC
- Case Identification: 1:19-cv-00535, E.D. Cal., 04/24/2019
- Venue Allegations: Venue is alleged to be proper in the Eastern District of California because Defendant is a California corporation with its headquarters and a regular and established place of business in Fresno, where it allegedly committed acts of infringement.
- Core Dispute: Plaintiff alleges that Defendant’s photoluminescent exit signs infringe patents related to a method of concentrating phosphor particles near the sign's surface to enhance brightness.
- Technical Context: The technology concerns non-electrical, photoluminescent ("glow-in-the-dark") safety signage, which provides an energy-efficient and fail-safe alternative to electrically powered emergency lighting.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendant with notice of the patents-in-suit via a letter in April 2018, a telephone call with Defendant's CEO in May 2018, and a second letter in October 2018 after commissioning its own testing of the accused products. This history of alleged pre-suit notice forms the basis for the willfulness claim.
Case Timeline
| Date | Event |
|---|---|
| 2011-02-11 | Plaintiff AfterGlow in business |
| 2011-03-14 | Earliest Priority Date for ’423 and ’378 Patents |
| 2012-10-16 | U.S. Patent No. 8,286,378 Issues |
| 2013-07-09 | U.S. Patent No. 8,479,423 Issues |
| 2018-02-28 | Plaintiff identifies alleged infringing sales (approximate date) |
| 2018-04-26 | Plaintiff sends first notice letter to Defendant |
| 2018-05-01 | Plaintiff's counsel speaks with Defendant's CEO |
| 2018-10-02 | Plaintiff sends second notice letter to Defendant after testing |
| 2019-04-24 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,479,423 - Advanced Photoluminescent Components and Formulation/Fabrication Methods for Production Thereof (Issued Jul. 9, 2013)
The Invention Explained
- Problem Addressed: The patent describes that in conventional photoluminescent (PL) products, the light-emitting phosphor particles are often distributed evenly throughout a polymer. This is inefficient, as phosphors deep within the material may not be sufficiently activated by ambient light, and any light they do emit may be scattered or absorbed before it can escape the surface (’423 Patent, col. 4:1-9).
- The Patented Solution: The invention proposes a photoluminescent sign where the phosphor particles are not distributed evenly. Instead, there is a greater weight concentration of particles in a "first region" near the light-emitting surface than in a "second region" deeper inside the material (’423 Patent, Abstract; col. 2:10-20). This non-homogenous distribution, illustrated in Figure 2A of the patent, concentrates the light-emitting capability at the surface, which is intended to increase the sign's perceived brightness and efficiency (’423 Patent, col. 5:11-25; Fig. 2A).
- Technical Importance: This design aims to create brighter and more efficient passive safety lighting, enhancing visibility in emergency situations without the cost, maintenance, or failure points of electrical systems (’423 Patent, col. 4:5-9).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2-5, 9, 12, and 17 (Compl. ¶25).
- Independent Claim 1:
- A photoluminescent sign comprising: a base plate; and
- an object shaped as a symbol and disposed on the base plate, said object having,
- a polymer matrix having a light-emitting exterior surface for emission of photoluminescent light therefrom and an opposite surface facing the base plate,
- a plurality of UV or visible-light excitable phosphor particles included in the polymer matrix, and
- a weight concentration of the phosphor particles in the polymer matrix being greater in a first region of the polymer matrix than in a second region of the polymer matrix.
U.S. Patent No. 8,286,378 - Advanced Photoluminescent Components and Formulation/Fabrication Methods for Production Thereof (Issued Oct. 16, 2012)
The Invention Explained
- Problem Addressed: As with its continuation patent (the ’423 Patent), the ’378 Patent identifies the problem of inefficient light emission in products where photoluminescent phosphors are randomly or evenly dispersed throughout a polymer matrix (’378 Patent, col. 4:1-9).
- The Patented Solution: The patent discloses a photoluminescent device with a polymer matrix where the concentration of phosphor particles is intentionally greater in an "exterior region" proximate to the light-emitting surface than in an "interior region" of the matrix (’378 Patent, Abstract). This preferential dispersion is described as a way to improve performance by ensuring more phosphors are positioned to both absorb charge and emit light effectively to a viewer (’378 Patent, col. 7:3-9).
- Technical Importance: The invention provides a method for manufacturing more effective "glow-in-the-dark" components, improving the performance of passive, non-electrical safety markings by optimizing the placement of the active phosphors (’378 Patent, col. 4:5-9).
Key Claims at a Glance
- The complaint asserts independent claims 1 and 19, and dependent claims 5, 11, 20-21, and 29-30 (Compl. ¶31).
- Independent Claim 1:
- A photoluminescent device comprising:
- a polymer matrix having a light-emitting exterior surface for emission of photoluminescent light therefrom; and
- a plurality of UV or visible-light excited phosphor particles included in the polymer matrix; and
- the phosphor particles having a concentration greater in an exterior region of the polymer matrix proximate the light-emitting exterior surface than in an interior region of the polymer matrix.
III. The Accused Instrumentality
Product Identification
- The accused products are Defendant BPL's photoluminescent (PL) products, including its PL EXIT signs, and specifically its "Centurion 100' EXIT signs" (Compl. ¶¶ 15-16).
Functionality and Market Context
- The accused products are non-electrical, "glow-in-the-dark" safety signs that absorb ambient light and subsequently emit it for visibility in low-light or power-outage scenarios (Compl. ¶9, 15). The complaint alleges that BPL is a direct competitor to AfterGlow and that the accused signs are rated for 100-foot visibility, suggesting they compete in the same market for high-performance safety equipment (Compl. ¶¶ 15-16). The complaint alleges that Plaintiff's testing of the letters from a BPL sign demonstrated the infringing features (Compl. ¶¶ 19-20). The complaint includes a photograph, described as Exhibit D, of the specific BPL EXIT sign that was tested (Compl. ¶19).
IV. Analysis of Infringement Allegations
'423 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| an object shaped as a symbol and disposed on the base plate | The accused product is an EXIT sign with letters (symbols) disposed on it. | ¶16 | col. 22:20-22 |
| a polymer matrix | The letters of the BPL sign allegedly include a "polymer matrix." | ¶20 | col. 22:23-26 |
| a plurality of...phosphor particles included in the polymer matrix | The letters of the BPL sign allegedly include "a plurality of UV or visible-light excited phosphor particles included in the polymer matrix." | ¶20 | col. 22:27-29 |
| a weight concentration of the phosphor particles...being greater in a first region...than in a second region | Testing of the accused BPL sign allegedly demonstrated that the phosphor particles have a concentration greater in an exterior region of the polymer matrix than in an interior region. | ¶20 | col. 22:30-35 |
'378 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a polymer matrix having a light-emitting exterior surface | The accused EXIT signs are comprised of a polymer matrix that forms the letters which emit light. | ¶¶19-20 | col. 24:18-20 |
| a plurality of...phosphor particles included in the polymer matrix | The polymer matrix of the accused signs allegedly includes phosphor particles. | ¶20 | col. 24:21-23 |
| the phosphor particles having a concentration greater in an exterior region...than in an interior region | The complaint alleges that testing confirmed the accused signs' letters have a phosphor particle concentration greater near the surface than deeper inside. To support this, the complaint includes what it describes as scanning electron microscope images from its testing (Compl. ¶20, Ex. F & G). | ¶20 | col. 24:24-29 |
- Identified Points of Contention:
- Factual Question: The primary point of contention will be factual: does the accused product's polymer matrix exhibit a "concentration [of phosphor particles] greater in an exterior region...than in an interior region" as required by the claims? The complaint's infringement theory rests entirely on its own testing, the methodology and results of which will be a central focus of discovery and expert dispute.
- Scope Question: A key question for the court will be how to measure the "concentration" and what quantum of difference is sufficient to meet the "greater than" limitation. The analysis will likely involve debates over whether this requires a specific gradient achieved through a particular manufacturing process (e.g., settling) or if any measurable differential, however slight, satisfies the claim language.
V. Key Claim Terms for Construction
- The Term: "concentration greater in an exterior region ... than in an interior region" (from the ’378 Patent) and "weight concentration ... being greater in a first region ... than in a second region" (from the ’423 Patent).
- Context and Importance: This limitation lies at the heart of the patented invention and the infringement dispute. The definition of these terms—particularly what constitutes an "exterior region" versus an "interior region" and what magnitude of difference is required for the concentration to be "greater"—will be dispositive. Practitioners may focus on this term because it is not defined with mathematical precision in the claims, opening the door to arguments based on the specification.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language of the claims does not set a specific numerical threshold for the concentration difference, which could support an argument that any statistically significant and measurable difference meets the limitation (’378 Patent, col. 24:24-29).
- Evidence for a Narrower Interpretation: The specification discloses specific embodiments where the concentration in the exterior region is substantially larger, for example "2-5 times, 5-50 times, or 50-100 times larger" than in the interior region (’378 Patent, col. 24:30-34). A defendant may argue that these examples cabin the claim scope to a significant, material gradient rather than a minimal or incidental one.
VI. Other Allegations
- Willful Infringement: The complaint alleges willful infringement based on Defendant’s alleged pre-suit knowledge of the patents-in-suit. This knowledge is alleged to stem from an April 26, 2018 notice letter, a subsequent May 1, 2018 telephone conference between the parties, and a follow-up letter on October 2, 2018 demanding cessation of infringement after Plaintiff's testing allegedly confirmed infringement (Compl. ¶¶ 17, 21, 27, 33).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of evidentiary proof: What does a forensic analysis of the accused signs actually show about the distribution of phosphor particles? The case will likely feature a "battle of the experts" focused on the testing methodologies and results to determine if the accused products physically embody the concentration gradient required by the asserted claims.
- The case will also turn on a question of claim construction: How much of a difference is required to satisfy the "concentration greater" limitation? The court's interpretation—whether it reads the claim to cover any detectable difference or a more substantial gradient informed by the specification's examples—will be critical in defining the boundary between infringing and non-infringing products.